shithub: hugo

Download patch

ref: a03c631c420a03f9d90699abdf9be7e4fca0ff61
parent: 167c01530bb295c8b8d35921eb27ffa5bee76dfe
author: Bjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com>
date: Tue Dec 10 14:56:44 EST 2019

Rework template handling for function and map lookups

This is a big commit, but it deletes lots of code and simplifies a lot.

* Resolving the template funcs at execution time means we don't have to create template clones per site
* Having a custom map resolver means that we can remove the AST lower case transformation for the special lower case Params map

Not only is the above easier to reason about, it's also faster, especially if you have more than one language, as in the benchmark below:

```
name                          old time/op    new time/op    delta
SiteNew/Deep_content_tree-16    53.7ms ± 0%    48.1ms ± 2%  -10.38%  (p=0.029 n=4+4)

name                          old alloc/op   new alloc/op   delta
SiteNew/Deep_content_tree-16    41.0MB ± 0%    36.8MB ± 0%  -10.26%  (p=0.029 n=4+4)

name                          old allocs/op  new allocs/op  delta
SiteNew/Deep_content_tree-16      481k ± 0%      410k ± 0%  -14.66%  (p=0.029 n=4+4)
```

This should be even better if you also have lots of templates.

Closes #6594

--- a/commands/server.go
+++ b/commands/server.go
@@ -16,6 +16,7 @@
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -33,7 +34,6 @@
 	"github.com/pkg/errors"
 
 	"github.com/gohugoio/hugo/livereload"
-	"github.com/gohugoio/hugo/tpl"
 
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/helpers"
@@ -287,7 +287,7 @@
 type fileServer struct {
 	baseURLs      []string
 	roots         []string
-	errorTemplate tpl.Template
+	errorTemplate func(err interface{}) (io.Reader, error)
 	c             *commandeer
 	s             *serverCmd
 }
@@ -335,8 +335,7 @@
 				err := f.c.getErrorWithContext()
 				if err != nil {
 					w.WriteHeader(500)
-					var b bytes.Buffer
-					err := f.errorTemplate.Execute(&b, err)
+					r, err := f.errorTemplate(err)
 					if err != nil {
 						f.c.logger.ERROR.Println(err)
 					}
@@ -344,7 +343,7 @@
 					if !f.c.paused {
 						port = f.c.Cfg.GetInt("liveReloadPort")
 					}
-					fmt.Fprint(w, injectLiveReloadScript(&b, port))
+					fmt.Fprint(w, injectLiveReloadScript(r, port))
 
 					return
 				}
@@ -422,11 +421,15 @@
 	}
 
 	srv := &fileServer{
-		baseURLs:      baseURLs,
-		roots:         roots,
-		c:             c,
-		s:             s,
-		errorTemplate: templ,
+		baseURLs: baseURLs,
+		roots:    roots,
+		c:        c,
+		s:        s,
+		errorTemplate: func(ctx interface{}) (io.Reader, error) {
+			b := &bytes.Buffer{}
+			err := c.hugo().Tmpl.Execute(templ, b, ctx)
+			return b, err
+		},
 	}
 
 	doLiveReload := !c.Cfg.GetBool("disableLiveReload")
--- a/create/content_template_handler.go
+++ b/create/content_template_handler.go
@@ -129,7 +129,7 @@
 	archetypeTemplate = []byte(archetypeShortcodeReplacementsPre.Replace(string(archetypeTemplate)))
 
 	// Reuse the Hugo template setup to get the template funcs properly set up.
-	templateHandler := s.Deps.Tmpl.(tpl.TemplateHandler)
+	templateHandler := s.Deps.Tmpl.(tpl.TemplateManager)
 	templateName := "_text/" + helpers.Filename(archetypeFilename)
 	if err := templateHandler.AddTemplate(templateName, string(archetypeTemplate)); err != nil {
 		return nil, errors.Wrapf(err, "Failed to parse archetype file %q:", archetypeFilename)
@@ -138,7 +138,7 @@
 	templ, _ := templateHandler.Lookup(templateName)
 
 	var buff bytes.Buffer
-	if err := templ.Execute(&buff, data); err != nil {
+	if err := templateHandler.Execute(templ, &buff, data); err != nil {
 		return nil, errors.Wrapf(err, "Failed to process archetype file %q:", archetypeFilename)
 	}
 
--- a/deps/deps.go
+++ b/deps/deps.go
@@ -37,8 +37,8 @@
 	// Used to log warnings that may repeat itself many times.
 	DistinctWarningLog *helpers.DistinctLogger
 
-	// The templates to use. This will usually implement the full tpl.TemplateHandler.
-	Tmpl tpl.TemplateFinder `json:"-"`
+	// The templates to use. This will usually implement the full tpl.TemplateManager.
+	Tmpl tpl.TemplateHandler `json:"-"`
 
 	// We use this to parse and execute ad-hoc text templates.
 	TextTmpl tpl.TemplateParseFinder `json:"-"`
@@ -77,8 +77,11 @@
 	OutputFormatsConfig output.Formats
 
 	templateProvider ResourceProvider
-	WithTemplate     func(templ tpl.TemplateHandler) error `json:"-"`
+	WithTemplate     func(templ tpl.TemplateManager) error `json:"-"`
 
+	// Used in tests
+	OverloadedTemplateFuncs map[string]interface{}
+
 	translationProvider ResourceProvider
 
 	Metrics metrics.Provider
@@ -151,8 +154,8 @@
 }
 
 // TemplateHandler returns the used tpl.TemplateFinder as tpl.TemplateHandler.
-func (d *Deps) TemplateHandler() tpl.TemplateHandler {
-	return d.Tmpl.(tpl.TemplateHandler)
+func (d *Deps) TemplateHandler() tpl.TemplateManager {
+	return d.Tmpl.(tpl.TemplateManager)
 }
 
 // LoadResources loads translations and templates.
@@ -239,24 +242,25 @@
 	distinctWarnLogger := helpers.NewDistinctLogger(logger.WARN)
 
 	d := &Deps{
-		Fs:                  fs,
-		Log:                 logger,
-		DistinctErrorLog:    distinctErrorLogger,
-		DistinctWarningLog:  distinctWarnLogger,
-		templateProvider:    cfg.TemplateProvider,
-		translationProvider: cfg.TranslationProvider,
-		WithTemplate:        cfg.WithTemplate,
-		PathSpec:            ps,
-		ContentSpec:         contentSpec,
-		SourceSpec:          sp,
-		ResourceSpec:        resourceSpec,
-		Cfg:                 cfg.Language,
-		Language:            cfg.Language,
-		Site:                cfg.Site,
-		FileCaches:          fileCaches,
-		BuildStartListeners: &Listeners{},
-		Timeout:             time.Duration(timeoutms) * time.Millisecond,
-		globalErrHandler:    &globalErrHandler{},
+		Fs:                      fs,
+		Log:                     logger,
+		DistinctErrorLog:        distinctErrorLogger,
+		DistinctWarningLog:      distinctWarnLogger,
+		templateProvider:        cfg.TemplateProvider,
+		translationProvider:     cfg.TranslationProvider,
+		WithTemplate:            cfg.WithTemplate,
+		OverloadedTemplateFuncs: cfg.OverloadedTemplateFuncs,
+		PathSpec:                ps,
+		ContentSpec:             contentSpec,
+		SourceSpec:              sp,
+		ResourceSpec:            resourceSpec,
+		Cfg:                     cfg.Language,
+		Language:                cfg.Language,
+		Site:                    cfg.Site,
+		FileCaches:              fileCaches,
+		BuildStartListeners:     &Listeners{},
+		Timeout:                 time.Duration(timeoutms) * time.Millisecond,
+		globalErrHandler:        &globalErrHandler{},
 	}
 
 	if cfg.Cfg.GetBool("templateMetrics") {
@@ -344,7 +348,9 @@
 
 	// Template handling.
 	TemplateProvider ResourceProvider
-	WithTemplate     func(templ tpl.TemplateHandler) error
+	WithTemplate     func(templ tpl.TemplateManager) error
+	// Used in tests
+	OverloadedTemplateFuncs map[string]interface{}
 
 	// i18n handling.
 	TranslationProvider ResourceProvider
--- a/hugolib/alias.go
+++ b/hugolib/alias.go
@@ -15,6 +15,7 @@
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"html/template"
 	"io"
@@ -31,27 +32,15 @@
 	"github.com/gohugoio/hugo/tpl"
 )
 
-const (
-	alias      = "<!DOCTYPE html><html><head><title>{{ .Permalink }}</title><link rel=\"canonical\" href=\"{{ .Permalink }}\"/><meta name=\"robots\" content=\"noindex\"><meta charset=\"utf-8\" /><meta http-equiv=\"refresh\" content=\"0; url={{ .Permalink }}\" /></head></html>"
-	aliasXHtml = "<!DOCTYPE html><html xmlns=\"http://www.w3.org/1999/xhtml\"><head><title>{{ .Permalink }}</title><link rel=\"canonical\" href=\"{{ .Permalink }}\"/><meta name=\"robots\" content=\"noindex\"><meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\" /><meta http-equiv=\"refresh\" content=\"0; url={{ .Permalink }}\" /></head></html>"
-)
-
 var defaultAliasTemplates *template.Template
 
-func init() {
-	//TODO(bep) consolidate
-	defaultAliasTemplates = template.New("")
-	template.Must(defaultAliasTemplates.New("alias").Parse(alias))
-	template.Must(defaultAliasTemplates.New("alias-xhtml").Parse(aliasXHtml))
-}
-
 type aliasHandler struct {
-	t         tpl.TemplateFinder
+	t         tpl.TemplateHandler
 	log       *loggers.Logger
 	allowRoot bool
 }
 
-func newAliasHandler(t tpl.TemplateFinder, l *loggers.Logger, allowRoot bool) aliasHandler {
+func newAliasHandler(t tpl.TemplateHandler, l *loggers.Logger, allowRoot bool) aliasHandler {
 	return aliasHandler{t, l, allowRoot}
 }
 
@@ -60,26 +49,20 @@
 	page.Page
 }
 
-func (a aliasHandler) renderAlias(isXHTML bool, permalink string, p page.Page) (io.Reader, error) {
-	t := "alias"
-	if isXHTML {
-		t = "alias-xhtml"
-	}
+func (a aliasHandler) renderAlias(permalink string, p page.Page) (io.Reader, error) {
 
 	var templ tpl.Template
 	var found bool
 
-	if a.t != nil {
-		templ, found = a.t.Lookup("alias.html")
-	}
-
+	templ, found = a.t.Lookup("alias.html")
 	if !found {
-		def := defaultAliasTemplates.Lookup(t)
-		if def != nil {
-			templ = &tpl.TemplateAdapter{Template: def}
+		// TODO(bep) consolidate
+		templ, found = a.t.Lookup("_internal/alias.html")
+		if !found {
+			return nil, errors.New("no alias template found")
 		}
-
 	}
+
 	data := aliasPage{
 		permalink,
 		p,
@@ -86,7 +69,7 @@
 	}
 
 	buffer := new(bytes.Buffer)
-	err := templ.Execute(buffer, data)
+	err := a.t.Execute(templ, buffer, data)
 	if err != nil {
 		return nil, err
 	}
@@ -100,8 +83,6 @@
 func (s *Site) publishDestAlias(allowRoot bool, path, permalink string, outputFormat output.Format, p page.Page) (err error) {
 	handler := newAliasHandler(s.Tmpl, s.Log, allowRoot)
 
-	isXHTML := strings.HasSuffix(path, ".xhtml")
-
 	s.Log.DEBUG.Println("creating alias:", path, "redirecting to", permalink)
 
 	targetPath, err := handler.targetPathAlias(path)
@@ -109,7 +90,7 @@
 		return err
 	}
 
-	aliasContent, err := handler.renderAlias(isXHTML, permalink, p)
+	aliasContent, err := handler.renderAlias(permalink, p)
 	if err != nil {
 		return err
 	}
--- a/hugolib/case_insensitive_test.go
+++ b/hugolib/case_insensitive_test.go
@@ -14,7 +14,6 @@
 package hugolib
 
 import (
-	"fmt"
 	"path/filepath"
 	"testing"
 
@@ -231,77 +230,4 @@
 		"index2|Page: flower|",
 		"index2|Site: yellow|",
 	)
-}
-
-// TODO1
-func TestCaseInsensitiveConfigurationForAllTemplateEngines(t *testing.T) {
-	t.Parallel()
-
-	noOp := func(s string) string {
-		return s
-	}
-
-	for _, config := range []struct {
-		suffix        string
-		templateFixer func(s string) string
-	}{
-		//{"amber", amberFixer},
-		{"html", noOp},
-		//{"ace", noOp},
-	} {
-		doTestCaseInsensitiveConfigurationForTemplateEngine(t, config.suffix, config.templateFixer)
-
-	}
-
-}
-
-func doTestCaseInsensitiveConfigurationForTemplateEngine(t *testing.T, suffix string, templateFixer func(s string) string) {
-	c := qt.New(t)
-	mm := afero.NewMemMapFs()
-
-	caseMixingTestsWriteCommonSources(t, mm)
-
-	cfg, err := LoadConfigDefault(mm)
-	c.Assert(err, qt.IsNil)
-
-	fs := hugofs.NewFrom(mm, cfg)
-
-	th := newTestHelper(cfg, fs, t)
-
-	t.Log("Testing", suffix)
-
-	templTemplate := `
-p
-	|
-	| Page Colors: {{ .Params.CoLOR }}|{{ .Params.Colors.Blue }}
-	| Site Colors: {{ .Site.Params.COlOR }}|{{ .Site.Params.COLORS.YELLOW }}
-	| {{ .Content }}
-
-`
-
-	templ := templateFixer(templTemplate)
-
-	t.Log(templ)
-
-	writeSource(t, fs, filepath.Join("layouts", "_default", fmt.Sprintf("single.%s", suffix)), templ)
-
-	sites, err := NewHugoSites(deps.DepsCfg{Fs: fs, Cfg: cfg})
-
-	if err != nil {
-		t.Fatalf("Failed to create sites: %s", err)
-	}
-
-	err = sites.Build(BuildCfg{})
-
-	if err != nil {
-		t.Fatalf("Failed to build sites: %s", err)
-	}
-
-	th.assertFileContent(filepath.Join("public", "nn", "sect1", "page1", "index.html"),
-		"Page Colors: red|heavenly",
-		"Site Colors: green|yellow",
-		"Shortcode Page: red|heavenly",
-		"Shortcode Site: green|yellow",
-	)
-
 }
--- a/hugolib/embedded_shortcodes_test.go
+++ b/hugolib/embedded_shortcodes_test.go
@@ -27,7 +27,6 @@
 	"github.com/gohugoio/hugo/deps"
 
 	qt "github.com/frankban/quicktest"
-	"github.com/gohugoio/hugo/tpl"
 )
 
 const (
@@ -334,11 +333,6 @@
 
 		cfg.Set("privacy", this.privacy)
 
-		withTemplate := func(templ tpl.TemplateHandler) error {
-			templ.(tpl.TemplateTestMocker).SetFuncs(tweetFuncMap)
-			return nil
-		}
-
 		writeSource(t, fs, filepath.Join("content", "simple.md"), fmt.Sprintf(`---
 title: Shorty
 ---
@@ -345,7 +339,7 @@
 %s`, this.in))
 		writeSource(t, fs, filepath.Join("layouts", "_default", "single.html"), `{{ .Content }}`)
 
-		buildSingleSite(t, deps.DepsCfg{Fs: fs, Cfg: cfg, WithTemplate: withTemplate}, BuildCfg{})
+		buildSingleSite(t, deps.DepsCfg{Fs: fs, Cfg: cfg, OverloadedTemplateFuncs: tweetFuncMap}, BuildCfg{})
 
 		th.assertFileContentRegexp(filepath.Join("public", "simple", "index.html"), this.expected)
 
@@ -389,11 +383,6 @@
 om:0; margin-top:8px; overflow:hidden; padding:8px 0 7px; text-align:center; text-overflow:ellipsis; white-space:nowrap;\"\u003e\u003ca href=\"https://www.instagram.com/p/BMokmydjG-M/\" style=\" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; font-style:normal; font-weight:normal; line-height:17px; text-decoration:none;\" target=\"_blank\"\u003eA photo posted by Instagram (@instagram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
 			`(?s)<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; .*<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>`,
 		},
-ng:8px 0 7px; text-align:center; text-overflow:ellipsis; white-space:nowrap;\"\u003e\u003ca href=\"https://www.instagram.com/p/BMokmydjG-M/\" style=\" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; font-style:normal; font-weight:normal; line-height:17px; text-decoration:none;\" target=\"_blank\"\u003eA photo posted by Instagram (@instagram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
-			`(?s)<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; .*<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>`,
-		},
-	} {
-		// overload getJSON to return mock API response from Instagram
 /\" style=\" color:#c9c8cd; font-family:Arial,sans-serif; font-size:14px; font-style:normal; font-weight:normal; line-height:17px; text-decoration:none;\" target=\"_blank\"\u003eA photo posted by Instagram (@instagram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
 			`(?s)<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; .*<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>`,
 		},
@@ -400,7 +389,7 @@
 nt-weight:normal; line-height:17px; text-decoration:none;\" target=\"_blank\"\u003eA photo posted by Instagram (@instagram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
 			`(?s)<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; .*<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>`,
 		},
-ram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
+nt-style:normal; font-weight:normal; line-height:17px; text-decoration:none;\" target=\"_blank\"\u003eA photo posted by Instagram (@instagram)\u003c/a\u003e on \u003ctime style=\" font-family:Arial,sans-serif; font-size:14px; line-height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
 height:17px;\" datetime=\"2016-11-10T15:02:28+00:00\"\u003eNov 10, 2016 at 7:02am PST\u003c/time\u003e\u003c/p\u003e\u003c/div\u003e\u003c/blockquote\u003e\n\u003cscript async defer src=\"//platform.instagram.com/en_US/embeds.js\"\u003e\u003c/script\u003e", "width": 658, "version": "1.0", "author_url": "https://www.instagram.com/instagram", "author_id": 25025320, "type": "rich"}`,
 			`(?s)<blockquote class="instagram-media" data-instgrm-version="7" style=" background:#FFF; border:0; .*<script async defer src="//platform.instagram.com/en_US/embeds.js"></script>`,
 		},
--- a/hugolib/hugo_modules_test.go
+++ b/hugolib/hugo_modules_test.go
@@ -42,10 +42,10 @@
 func TestHugoModules(t *testing.T) {
 	t.Parallel()
 
-	if hugo.GoMinorVersion() < 12 {
+	if !isCI() || hugo.GoMinorVersion() < 12 {
 		// https://github.com/golang/go/issues/26794
 		// There were some concurrent issues with Go modules in < Go 12.
-		t.Skip("skip this for Go <= 1.11 due to a bug in Go's stdlib")
+		t.Skip("skip this on local host and for Go <= 1.11 due to a bug in Go's stdlib")
 	}
 
 	if testing.Short() {
--- a/hugolib/hugo_sites.go
+++ b/hugolib/hugo_sites.go
@@ -426,8 +426,8 @@
 	return newHugoSites(cfg, sites...)
 }
 
-func (s *Site) withSiteTemplates(withTemplates ...func(templ tpl.TemplateHandler) error) func(templ tpl.TemplateHandler) error {
-	return func(templ tpl.TemplateHandler) error {
+func (s *Site) withSiteTemplates(withTemplates ...func(templ tpl.TemplateManager) error) func(templ tpl.TemplateManager) error {
+	return func(templ tpl.TemplateManager) error {
 		if err := templ.LoadTemplates(""); err != nil {
 			return err
 		}
--- a/hugolib/hugo_smoke_test.go
+++ b/hugolib/hugo_smoke_test.go
@@ -21,6 +21,27 @@
 	qt "github.com/frankban/quicktest"
 )
 
+// The most basic build test.
+func TestHello(t *testing.T) {
+	t.Parallel()
+	b := newTestSitesBuilder(t)
+	b.WithConfigFile("toml", `
+baseURL="https://example.org"
+disableKinds = ["taxonomy", "taxonomyTerm", "section", "page"]
+`)
+	b.WithContent("p1", `
+---
+title: Page
+---
+
+`)
+	b.WithTemplates("index.html", `Site: {{ .Site.Language.Lang | upper }}`)
+
+	b.Build(BuildCfg{})
+
+	b.AssertFileContent("public/index.html", `Site: EN`)
+}
+
 func TestSmoke(t *testing.T) {
 	t.Parallel()
 
--- a/hugolib/page.go
+++ b/hugolib/page.go
@@ -480,7 +480,7 @@
 			templ, _ = p.s.Tmpl.Lookup(layout + ".html")
 		}
 		if templ != nil {
-			res, err := executeToString(templ, p)
+			res, err := executeToString(p.s.Tmpl, templ, p)
 			if err != nil {
 				p.s.SendError(p.wrapError(errors.Wrapf(err, ".Render: failed to execute template %q v", layout)))
 				return ""
--- a/hugolib/page__per_output.go
+++ b/hugolib/page__per_output.go
@@ -411,10 +411,10 @@
 	return t.paths
 }
 
-func executeToString(templ tpl.Template, data interface{}) (string, error) {
+func executeToString(h tpl.TemplateHandler, templ tpl.Template, data interface{}) (string, error) {
 	b := bp.GetBuffer()
 	defer bp.PutBuffer(b)
-	if err := templ.Execute(b, data); err != nil {
+	if err := h.Execute(templ, b, data); err != nil {
 		return "", err
 	}
 	return b.String(), nil
--- a/hugolib/page_test.go
+++ b/hugolib/page_test.go
@@ -459,7 +459,7 @@
 	}
 
 	cnt := content(p)
-	if cnt != "<p>The <a href=\"http://gohugo.io/\">best static site generator</a>.<sup id=\"fnref:1\"><a href=\"#fn:1\" class=\"footnote-ref\" role=\"doc-noteref\">1</a></sup></p>\n<section class=\"footnotes\" role=\"doc-endnotes\">\n<hr>\n<ol>\n<li id=\"fn:1\" role=\"doc-endnote\">\n<p>Many people say so. <a href=\"#fnref:1\" class=\"footnote-backref\" role=\"doc-backlink\">&#x21a9;&#xfe0e;</a></p>\n</li>\n</ol>\n</section>" {
+	if cnt != "<p>The <a href=\"http://gohugo.io/\">best static site generator</a>.<sup id=\"fnref:1\"><a href=\"#fn:1\" class=\"footnote-ref\" role=\"doc-noteref\">1</a></sup></p>\n<section class=\"footnotes\" role=\"doc-endnotes\">\n<hr>\n<ol>\n<li id=\"fn:1\" role=\"doc-endnote\">\n<p>Many people say so.<a href=\"#fnref:1\" class=\"footnote-backref\" role=\"doc-backlink\">&#8617;</a></p>\n</li>\n</ol>\n</section>" {
 		t.Fatalf("Got content:\n%q", cnt)
 	}
 }
--- a/hugolib/shortcode.go
+++ b/hugolib/shortcode.go
@@ -393,7 +393,7 @@
 
 	}
 
-	result, err := renderShortcodeWithPage(tmpl, data)
+	result, err := renderShortcodeWithPage(s.Tmpl, tmpl, data)
 
 	if err != nil && sc.isInline {
 		fe := herrors.ToFileError("html", err)
@@ -634,11 +634,11 @@
 	return source, nil
 }
 
-func renderShortcodeWithPage(tmpl tpl.Template, data *ShortcodeWithPage) (string, error) {
+func renderShortcodeWithPage(h tpl.TemplateHandler, tmpl tpl.Template, data *ShortcodeWithPage) (string, error) {
 	buffer := bp.GetBuffer()
 	defer bp.PutBuffer(buffer)
 
-	err := tmpl.Execute(buffer, data)
+	err := h.Execute(tmpl, buffer, data)
 	if err != nil {
 		return "", _errors.Wrap(err, "failed to process shortcode")
 	}
--- a/hugolib/shortcode_test.go
+++ b/hugolib/shortcode_test.go
@@ -36,12 +36,12 @@
 	qt "github.com/frankban/quicktest"
 )
 
-func CheckShortCodeMatch(t *testing.T, input, expected string, withTemplate func(templ tpl.TemplateHandler) error) {
+func CheckShortCodeMatch(t *testing.T, input, expected string, withTemplate func(templ tpl.TemplateManager) error) {
 	t.Helper()
 	CheckShortCodeMatchAndError(t, input, expected, withTemplate, false)
 }
 
-func CheckShortCodeMatchAndError(t *testing.T, input, expected string, withTemplate func(templ tpl.TemplateHandler) error, expectError bool) {
+func CheckShortCodeMatchAndError(t *testing.T, input, expected string, withTemplate func(templ tpl.TemplateManager) error, expectError bool) {
 	t.Helper()
 	cfg, fs := newTestCfg()
 
@@ -95,7 +95,7 @@
 // Issue #929
 func TestHyphenatedSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 
 		tem.AddTemplate("_internal/shortcodes/hyphenated-video.html", `Playing Video {{ .Get 0 }}`)
 		return nil
@@ -107,7 +107,7 @@
 // Issue #1753
 func TestNoTrailingNewline(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/a.html", `{{ .Get 0 }}`)
 		return nil
 	}
@@ -117,7 +117,7 @@
 
 func TestPositionalParamSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/video.html", `Playing Video {{ .Get 0 }}`)
 		return nil
 	}
@@ -131,7 +131,7 @@
 
 func TestPositionalParamIndexOutOfBounds(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/video.html", `Playing Video {{ with .Get 1 }}{{ . }}{{ else }}Missing{{ end }}`)
 		return nil
 	}
@@ -141,7 +141,7 @@
 // #5071
 func TestShortcodeRelated(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/a.html", `{{ len (.Site.RegularPages.Related .Page) }}`)
 		return nil
 	}
@@ -151,7 +151,7 @@
 
 func TestShortcodeInnerMarkup(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("shortcodes/a.html", `<div>{{ .Inner }}</div>`)
 		tem.AddTemplate("shortcodes/b.html", `**Bold**: <div>{{ .Inner }}</div>`)
 		return nil
@@ -175,7 +175,7 @@
 
 func TestNamedParamSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/img.html", `<img{{ with .Get "src" }} src="{{.}}"{{end}}{{with .Get "class"}} class="{{.}}"{{end}}>`)
 		return nil
 	}
@@ -190,7 +190,7 @@
 // Issue #2294
 func TestNestedNamedMissingParam(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/acc.html", `<div class="acc">{{ .Inner }}</div>`)
 		tem.AddTemplate("_internal/shortcodes/div.html", `<div {{with .Get "class"}} class="{{ . }}"{{ end }}>{{ .Inner }}</div>`)
 		tem.AddTemplate("_internal/shortcodes/div2.html", `<div {{with .Get 0}} class="{{ . }}"{{ end }}>{{ .Inner }}</div>`)
@@ -203,7 +203,7 @@
 
 func TestIsNamedParamsSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/bynameorposition.html", `{{ with .Get "id" }}Named: {{ . }}{{ else }}Pos: {{ .Get 0 }}{{ end }}`)
 		tem.AddTemplate("_internal/shortcodes/ifnamedparams.html", `<div id="{{ if .IsNamedParams }}{{ .Get "id" }}{{ else }}{{ .Get 0 }}{{end}}">`)
 		return nil
@@ -216,7 +216,7 @@
 
 func TestInnerSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/inside.html", `<div{{with .Get "class"}} class="{{.}}"{{end}}>{{ .Inner }}</div>`)
 		return nil
 	}
@@ -227,7 +227,7 @@
 
 func TestInnerSCWithMarkdown(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		// Note: In Hugo 0.55 we made it so any outer {{%'s inner content was rendered as part of the surrounding
 		// markup. This solved lots of problems, but it also meant that this test had to be adjusted.
 		tem.AddTemplate("_internal/shortcodes/wrapper.html", `<div{{with .Get "class"}} class="{{.}}"{{end}}>{{ .Inner }}</div>`)
@@ -250,7 +250,7 @@
 
 func TestNestedSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/scn1.html", `<div>Outer, inner is {{ .Inner }}</div>`)
 		tem.AddTemplate("_internal/shortcodes/scn2.html", `<div>SC2</div>`)
 		return nil
@@ -262,7 +262,7 @@
 
 func TestNestedComplexSC(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/row.html", `-row-{{ .Inner}}-rowStop-`)
 		tem.AddTemplate("_internal/shortcodes/column.html", `-col-{{.Inner    }}-colStop-`)
 		tem.AddTemplate("_internal/shortcodes/aside.html", `-aside-{{    .Inner  }}-asideStop-`)
@@ -278,7 +278,7 @@
 
 func TestParentShortcode(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/r1.html", `1: {{ .Get "pr1" }} {{ .Inner }}`)
 		tem.AddTemplate("_internal/shortcodes/r2.html", `2: {{ .Parent.Get "pr1" }}{{ .Get "pr2" }} {{ .Inner }}`)
 		tem.AddTemplate("_internal/shortcodes/r3.html", `3: {{ .Parent.Parent.Get "pr1" }}{{ .Parent.Get "pr2" }}{{ .Get "pr3" }} {{ .Inner }}`)
@@ -333,7 +333,7 @@
 // #1642
 func TestShortcodeWrappedInPIssue(t *testing.T) {
 	t.Parallel()
-	wt := func(tem tpl.TemplateHandler) error {
+	wt := func(tem tpl.TemplateManager) error {
 		tem.AddTemplate("_internal/shortcodes/bug.html", `xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx`)
 		return nil
 	}
@@ -564,7 +564,7 @@
 		sources[i] = [2]string{filepath.FromSlash(test.contentPath), test.content}
 	}
 
-	addTemplates := func(templ tpl.TemplateHandler) error {
+	addTemplates := func(templ tpl.TemplateManager) error {
 		templ.AddTemplate("_default/single.html", "{{.Content}} Word Count: {{ .WordCount }}")
 
 		templ.AddTemplate("_internal/shortcodes/b.html", `b`)
--- a/hugolib/site.go
+++ b/hugolib/site.go
@@ -474,7 +474,7 @@
 // The site will have a template system loaded and ready to use.
 // Note: This is mainly used in single site tests.
 // TODO(bep) test refactor -- remove
-func NewSiteDefaultLang(withTemplate ...func(templ tpl.TemplateHandler) error) (*Site, error) {
+func NewSiteDefaultLang(withTemplate ...func(templ tpl.TemplateManager) error) (*Site, error) {
 	v := viper.New()
 	if err := loadDefaultSettingsFor(v); err != nil {
 		return nil, err
@@ -486,7 +486,7 @@
 // The site will have a template system loaded and ready to use.
 // Note: This is mainly used in single site tests.
 // TODO(bep) test refactor -- remove
-func NewEnglishSite(withTemplate ...func(templ tpl.TemplateHandler) error) (*Site, error) {
+func NewEnglishSite(withTemplate ...func(templ tpl.TemplateManager) error) (*Site, error) {
 	v := viper.New()
 	if err := loadDefaultSettingsFor(v); err != nil {
 		return nil, err
@@ -495,8 +495,8 @@
 }
 
 // newSiteForLang creates a new site in the given language.
-func newSiteForLang(lang *langs.Language, withTemplate ...func(templ tpl.TemplateHandler) error) (*Site, error) {
-	withTemplates := func(templ tpl.TemplateHandler) error {
+func newSiteForLang(lang *langs.Language, withTemplate ...func(templ tpl.TemplateManager) error) (*Site, error) {
+	withTemplates := func(templ tpl.TemplateManager) error {
 		for _, wt := range withTemplate {
 			if err := wt(templ); err != nil {
 				return err
@@ -1589,7 +1589,7 @@
 		return nil
 	}
 
-	if err = templ.Execute(w, d); err != nil {
+	if err = s.Tmpl.Execute(templ, w, d); err != nil {
 		return _errors.Wrapf(err, "render of %q failed", name)
 	}
 	return
--- a/hugolib/sitemap_test.go
+++ b/hugolib/sitemap_test.go
@@ -50,7 +50,7 @@
 
 	depsCfg := deps.DepsCfg{Fs: fs, Cfg: cfg}
 
-	depsCfg.WithTemplate = func(templ tpl.TemplateHandler) error {
+	depsCfg.WithTemplate = func(templ tpl.TemplateManager) error {
 		if !internal {
 			templ.AddTemplate("sitemap.xml", sitemapTemplate)
 		}
--- a/hugolib/template_engines_test.go
+++ /dev/null
@@ -1,97 +1,0 @@
-// Copyright 2017 The Hugo Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package hugolib
-
-import (
-	"fmt"
-	"path/filepath"
-	"testing"
-
-	"github.com/gohugoio/hugo/deps"
-)
-
-// TODO1
-func TestAllTemplateEngines(t *testing.T) {
-	noOp := func(s string) string {
-		return s
-	}
-
-	for _, config := range []struct {
-		suffix        string
-		templateFixer func(s string) string
-	}{
-		//{"amber", amberFixer},
-		{"html", noOp},
-		//{"ace", noOp},
-	} {
-		config := config
-		t.Run(config.suffix,
-			func(t *testing.T) {
-				t.Parallel()
-				doTestTemplateEngine(t, config.suffix, config.templateFixer)
-			})
-	}
-
-}
-
-func doTestTemplateEngine(t *testing.T, suffix string, templateFixer func(s string) string) {
-
-	cfg, fs := newTestCfg()
-
-	t.Log("Testing", suffix)
-
-	templTemplate := `
-p
-	|
-	| Page Title: {{ .Title }}
-	br
-	| Page Content: {{ .Content }}
-	br
-	| {{ title "hello world" }}
-
-`
-
-	templShortcodeTemplate := `
-p
-	|
-	| Shortcode: {{ .IsNamedParams }}
-`
-
-	templ := templateFixer(templTemplate)
-	shortcodeTempl := templateFixer(templShortcodeTemplate)
-
-	writeSource(t, fs, filepath.Join("content", "p.md"), `
----
-title: My Title 
----
-My Content
-
-Shortcode: {{< myShort >}}
-
-`)
-
-	writeSource(t, fs, filepath.Join("layouts", "_default", fmt.Sprintf("single.%s", suffix)), templ)
-	writeSource(t, fs, filepath.Join("layouts", "shortcodes", fmt.Sprintf("myShort.%s", suffix)), shortcodeTempl)
-
-	s := buildSingleSite(t, deps.DepsCfg{Fs: fs, Cfg: cfg}, BuildCfg{})
-	th := newTestHelper(s.Cfg, s.Fs, t)
-
-	th.assertFileContent(filepath.Join("public", "p", "index.html"),
-		"Page Title: My Title",
-		"My Content",
-		"Hello World",
-		"Shortcode: false",
-	)
-
-}
--- a/hugolib/testhelpers_test.go
+++ b/hugolib/testhelpers_test.go
@@ -845,9 +845,9 @@
 	return th, h
 }
 
-func createWithTemplateFromNameValues(additionalTemplates ...string) func(templ tpl.TemplateHandler) error {
+func createWithTemplateFromNameValues(additionalTemplates ...string) func(templ tpl.TemplateManager) error {
 
-	return func(templ tpl.TemplateHandler) error {
+	return func(templ tpl.TemplateManager) error {
 		for i := 0; i < len(additionalTemplates); i += 2 {
 			err := templ.AddTemplate(additionalTemplates[i], additionalTemplates[i+1])
 			if err != nil {
--- a/langs/language.go
+++ b/langs/language.go
@@ -16,6 +16,7 @@
 import (
 	"sort"
 	"strings"
+	"sync"
 
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/config"
@@ -56,7 +57,9 @@
 
 	// These are params declared in the [params] section of the language merged with the
 	// site's params, the most specific (language) wins on duplicate keys.
-	params map[string]interface{}
+	params    map[string]interface{}
+	paramsMu  sync.Mutex
+	paramsSet bool
 
 	// These are config values, i.e. the settings declared outside of the [params] section of the language.
 	// This is the map Hugo looks in when looking for configuration values (baseURL etc.).
@@ -123,7 +126,15 @@
 func (l Languages) Swap(i, j int) { l[i], l[j] = l[j], l[i] }
 
 // Params retunrs language-specific params merged with the global params.
-func (l *Language) Params() map[string]interface{} {
+func (l *Language) Params() maps.Params {
+	// TODO(bep) this construct should not be needed. Create the
+	// language params in one go.
+	l.paramsMu.Lock()
+	defer l.paramsMu.Unlock()
+	if !l.paramsSet {
+		maps.ToLower(l.params)
+		l.paramsSet = true
+	}
 	return l.params
 }
 
@@ -163,7 +174,12 @@
 // SetParam sets a param with the given key and value.
 // SetParam is case-insensitive.
 func (l *Language) SetParam(k string, v interface{}) {
-	l.params[strings.ToLower(k)] = v
+	l.paramsMu.Lock()
+	defer l.paramsMu.Unlock()
+	if l.paramsSet {
+		panic("params cannot be changed once set")
+	}
+	l.params[k] = v
 }
 
 // GetBool returns the value associated with the key as a boolean.
--- a/resources/resource_transformers/templates/execute_as_template.go
+++ b/resources/resource_transformers/templates/execute_as_template.go
@@ -27,11 +27,12 @@
 type Client struct {
 	rs *resources.Spec
 
-	textTemplate tpl.TemplateParseFinder
+	templateHandler tpl.TemplateHandler
+	textTemplate    tpl.TemplateParseFinder
 }
 
 // New creates a new Client with the given specification.
-func New(rs *resources.Spec, textTemplate tpl.TemplateParseFinder) *Client {
+func New(rs *resources.Spec, h tpl.TemplateHandler, textTemplate tpl.TemplateParseFinder) *Client {
 	if rs == nil {
 		panic("must provice a resource Spec")
 	}
@@ -38,14 +39,15 @@
 	if textTemplate == nil {
 		panic("must provide a textTemplate")
 	}
-	return &Client{rs: rs, textTemplate: textTemplate}
+	return &Client{rs: rs, templateHandler: h, textTemplate: textTemplate}
 }
 
 type executeAsTemplateTransform struct {
-	rs           *resources.Spec
-	textTemplate tpl.TemplateParseFinder
-	targetPath   string
-	data         interface{}
+	rs              *resources.Spec
+	textTemplate    tpl.TemplateParseFinder
+	templateHandler tpl.TemplateHandler
+	targetPath      string
+	data            interface{}
 }
 
 func (t *executeAsTemplateTransform) Key() internal.ResourceTransformationKey {
@@ -61,14 +63,15 @@
 
 	ctx.OutPath = t.targetPath
 
-	return templ.Execute(ctx.To, t.data)
+	return t.templateHandler.Execute(templ, ctx.To, t.data)
 }
 
 func (c *Client) ExecuteAsTemplate(res resources.ResourceTransformer, targetPath string, data interface{}) (resource.Resource, error) {
 	return res.Transform(&executeAsTemplateTransform{
-		rs:           c.rs,
-		targetPath:   helpers.ToSlashTrimLeading(targetPath),
-		textTemplate: c.textTemplate,
-		data:         data,
+		rs:              c.rs,
+		targetPath:      helpers.ToSlashTrimLeading(targetPath),
+		templateHandler: c.templateHandler,
+		textTemplate:    c.textTemplate,
+		data:            data,
 	})
 }
--- a/scripts/fork_go_templates/main.go
+++ b/scripts/fork_go_templates/main.go
@@ -57,6 +57,8 @@
 		`"internal/fmtsort"`, `"github.com/gohugoio/hugo/tpl/internal/go_templates/fmtsort"`,
 		// Rename types and function that we want to overload.
 		"type state struct", "type stateOld struct",
+		"func (s *state) evalFunction", "func (s *state) evalFunctionOld",
+		"func (s *state) evalField(", "func (s *state) evalFieldOld(",
 	)
 
 	htmlTemplateReplacers = strings.NewReplacer(
--- a/tpl/collections/apply.go
+++ b/tpl/collections/apply.go
@@ -106,17 +106,8 @@
 
 func (ns *Namespace) lookupFunc(fname string) (reflect.Value, bool) {
 	if !strings.ContainsRune(fname, '.') {
-		templ, ok := ns.deps.Tmpl.(tpl.TemplateFuncsGetter)
-		if !ok {
-			panic("Needs a tpl.TemplateFuncsGetter")
-		}
-		fm := templ.GetFuncs()
-		fn, found := fm[fname]
-		if !found {
-			return reflect.Value{}, false
-		}
-
-		return reflect.ValueOf(fn), true
+		templ := ns.deps.Tmpl.(tpl.TemplateFuncGetter)
+		return templ.GetFunc(fname)
 	}
 
 	ss := strings.SplitN(fname, ".", 2)
--- a/tpl/collections/apply_test.go
+++ b/tpl/collections/apply_test.go
@@ -14,6 +14,8 @@
 package collections
 
 import (
+	"io"
+	"reflect"
 	"testing"
 
 	"fmt"
@@ -33,10 +35,17 @@
 	return nil, false, false
 }
 
-func (templateFinder) GetFuncs() map[string]interface{} {
-	return map[string]interface{}{
-		"print": fmt.Sprint,
+func (templateFinder) Execute(t tpl.Template, wr io.Writer, data interface{}) error {
+	return nil
+}
+
+func (templateFinder) GetFunc(name string) (reflect.Value, bool) {
+	if name == "dobedobedo" {
+		return reflect.Value{}, false
 	}
+
+	return reflect.ValueOf(fmt.Sprint), true
+
 }
 
 func TestApply(t *testing.T) {
--- a/tpl/internal/go_templates/texttemplate/exec.go
+++ b/tpl/internal/go_templates/texttemplate/exec.go
@@ -558,7 +558,7 @@
 	return s.evalField(dot, ident[n-1], node, args, final, receiver)
 }
 
-func (s *state) evalFunction(dot reflect.Value, node *parse.IdentifierNode, cmd parse.Node, args []parse.Node, final reflect.Value) reflect.Value {
+func (s *state) evalFunctionOld(dot reflect.Value, node *parse.IdentifierNode, cmd parse.Node, args []parse.Node, final reflect.Value) reflect.Value {
 	s.at(node)
 	name := node.Ident
 	function, ok := findFunction(name, s.tmpl)
@@ -571,7 +571,7 @@
 // evalField evaluates an expression like (.Field) or (.Field arg1 arg2).
 // The 'final' argument represents the return value from the preceding
 // value of the pipeline, if any.
-func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, args []parse.Node, final, receiver reflect.Value) reflect.Value {
+func (s *state) evalFieldOld(dot reflect.Value, fieldName string, node parse.Node, args []parse.Node, final, receiver reflect.Value) reflect.Value {
 	if !receiver.IsValid() {
 		if s.tmpl.option.missingKey == mapError { // Treat invalid value as missing map key.
 			s.errorf("nil data; no entry for key %q", fieldName)
--- a/tpl/internal/go_templates/texttemplate/hugo_exec.go
+++ /dev/null
@@ -1,38 +1,0 @@
-// Copyright 2019 The Hugo Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package template
-
-import (
-	"io"
-
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
-)
-
-/*
-
-This files contains the Hugo related addons. All the other files in this
-package is auto generated.
-
-*/
-
-// state represents the state of an execution. It's not part of the
-// template so that multiple executions of the same template
-// can execute in parallel.
-type state struct {
-	tmpl  *Template
-	wr    io.Writer
-	node  parse.Node // current node, for errors
-	vars  []variable // push-down stack of variable values.
-	depth int        // the height of the stack of executing templates.
-}
--- a/tpl/internal/go_templates/texttemplate/hugo_template.go
+++ b/tpl/internal/go_templates/texttemplate/hugo_template.go
@@ -27,15 +27,31 @@
 
 */
 
-// TODO1 name
+// Preparer prepares the template before execution.
 type Preparer interface {
 	Prepare() (*Template, error)
 }
 
-type TemplateExecutor struct {
+// ExecHelper allows some custom eval hooks.
+type ExecHelper interface {
+	GetFunc(name string) (reflect.Value, bool)
+	GetMapValue(receiver, key reflect.Value) (reflect.Value, bool)
 }
 
-func (t *TemplateExecutor) Execute(p Preparer, wr io.Writer, data interface{}) error {
+// Executer executes a given template.
+type Executer interface {
+	Execute(p Preparer, wr io.Writer, data interface{}) error
+}
+
+type executer struct {
+	helper ExecHelper
+}
+
+func NewExecuter(helper ExecHelper) Executer {
+	return &executer{helper: helper}
+}
+
+func (t *executer) Execute(p Preparer, wr io.Writer, data interface{}) error {
 	tmpl, err := p.Prepare()
 	if err != nil {
 		return err
@@ -47,9 +63,10 @@
 	}
 
 	state := &state{
-		tmpl: tmpl,
-		wr:   wr,
-		vars: []variable{{"$", value}},
+		helper: t.helper,
+		tmpl:   tmpl,
+		wr:     wr,
+		vars:   []variable{{"$", value}},
 	}
 
 	return tmpl.executeWithState(state, value)
@@ -62,6 +79,15 @@
 	return t, nil
 }
 
+func (t *Template) executeWithState(state *state, value reflect.Value) (err error) {
+	defer errRecover(&err)
+	if t.Tree == nil || t.Root == nil {
+		state.errorf("%q is an incomplete or empty template", t.Name())
+	}
+	state.walk(value, t.Root)
+	return
+}
+
 // Below are modifed structs etc.
 
 // state represents the state of an execution. It's not part of the
@@ -68,18 +94,116 @@
 // template so that multiple executions of the same template
 // can execute in parallel.
 type state struct {
-	tmpl  *Template
-	wr    io.Writer
-	node  parse.Node // current node, for errors
-	vars  []variable // push-down stack of variable values.
-	depth int        // the height of the stack of executing templates.
+	tmpl   *Template
+	helper ExecHelper
+	wr     io.Writer
+	node   parse.Node // current node, for errors
+	vars   []variable // push-down stack of variable values.
+	depth  int        // the height of the stack of executing templates.
 }
 
-func (t *Template) executeWithState(state *state, value reflect.Value) (err error) {
-	defer errRecover(&err)
-	if t.Tree == nil || t.Root == nil {
-		state.errorf("%q is an incomplete or empty template", t.Name())
+func (s *state) evalFunction(dot reflect.Value, node *parse.IdentifierNode, cmd parse.Node, args []parse.Node, final reflect.Value) reflect.Value {
+	s.at(node)
+	name := node.Ident
+
+	var function reflect.Value
+	var ok bool
+	if s.helper != nil {
+		function, ok = s.helper.GetFunc(name)
 	}
-	state.walk(value, t.Root)
-	return
+
+	if !ok {
+		function, ok = findFunction(name, s.tmpl)
+	}
+
+	if !ok {
+		s.errorf("%q is not a defined function", name)
+	}
+	return s.evalCall(dot, function, cmd, name, args, final)
+}
+
+// evalField evaluates an expression like (.Field) or (.Field arg1 arg2).
+// The 'final' argument represents the return value from the preceding
+// value of the pipeline, if any.
+func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, args []parse.Node, final, receiver reflect.Value) reflect.Value {
+	if !receiver.IsValid() {
+		if s.tmpl.option.missingKey == mapError { // Treat invalid value as missing map key.
+			s.errorf("nil data; no entry for key %q", fieldName)
+		}
+		return zero
+	}
+	typ := receiver.Type()
+	receiver, isNil := indirect(receiver)
+	if receiver.Kind() == reflect.Interface && isNil {
+		// Calling a method on a nil interface can't work. The
+		// MethodByName method call below would panic.
+		s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
+		return zero
+	}
+
+	// Unless it's an interface, need to get to a value of type *T to guarantee
+	// we see all methods of T and *T.
+	ptr := receiver
+	if ptr.Kind() != reflect.Interface && ptr.Kind() != reflect.Ptr && ptr.CanAddr() {
+		ptr = ptr.Addr()
+	}
+	if method := ptr.MethodByName(fieldName); method.IsValid() {
+		return s.evalCall(dot, method, node, fieldName, args, final)
+	}
+	hasArgs := len(args) > 1 || final != missingVal
+	// It's not a method; must be a field of a struct or an element of a map.
+	switch receiver.Kind() {
+	case reflect.Struct:
+		tField, ok := receiver.Type().FieldByName(fieldName)
+		if ok {
+			field := receiver.FieldByIndex(tField.Index)
+			if tField.PkgPath != "" { // field is unexported
+				s.errorf("%s is an unexported field of struct type %s", fieldName, typ)
+			}
+			// If it's a function, we must call it.
+			if hasArgs {
+				s.errorf("%s has arguments but cannot be invoked as function", fieldName)
+			}
+			return field
+		}
+	case reflect.Map:
+		// If it's a map, attempt to use the field name as a key.
+		nameVal := reflect.ValueOf(fieldName)
+		if nameVal.Type().AssignableTo(receiver.Type().Key()) {
+			if hasArgs {
+				s.errorf("%s is not a method but has arguments", fieldName)
+			}
+			var result reflect.Value
+			if s.helper != nil {
+				result, _ = s.helper.GetMapValue(receiver, nameVal)
+			} else {
+				result = receiver.MapIndex(nameVal)
+			}
+			if !result.IsValid() {
+				switch s.tmpl.option.missingKey {
+				case mapInvalid:
+					// Just use the invalid value.
+				case mapZeroValue:
+					result = reflect.Zero(receiver.Type().Elem())
+				case mapError:
+					s.errorf("map has no entry for key %q", fieldName)
+				}
+			}
+			return result
+		}
+	case reflect.Ptr:
+		etyp := receiver.Type().Elem()
+		if etyp.Kind() == reflect.Struct {
+			if _, ok := etyp.FieldByName(fieldName); !ok {
+				// If there's no such field, say "can't evaluate"
+				// instead of "nil pointer evaluating".
+				break
+			}
+		}
+		if isNil {
+			s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
+		}
+	}
+	s.errorf("can't evaluate field %s in type %s", fieldName, typ)
+	panic("not reached")
 }
--- /dev/null
+++ b/tpl/internal/go_templates/texttemplate/hugo_template_test.go
@@ -1,0 +1,71 @@
+// Copyright 2019 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package template
+
+import (
+	"bytes"
+	"reflect"
+	"strings"
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+)
+
+type TestStruct struct {
+	S string
+	M map[string]string
+}
+
+type execHelper struct {
+}
+
+func (e *execHelper) GetFunc(name string) (reflect.Value, bool) {
+	if name == "print" {
+		return zero, false
+	}
+	return reflect.ValueOf(func(s string) string {
+		return "hello " + s
+	}), true
+}
+
+func (e *execHelper) GetMapValue(m, key reflect.Value) (reflect.Value, bool) {
+	key = reflect.ValueOf(strings.ToLower(key.String()))
+	return m.MapIndex(key), true
+}
+
+func TestTemplateExecutor(t *testing.T) {
+	c := qt.New(t)
+
+	templ, err := New("").Parse(`
+{{ print "foo" }}
+{{ printf "hugo" }}
+Map: {{ .M.A }}
+
+`)
+
+	c.Assert(err, qt.IsNil)
+
+	ex := NewExecuter(&execHelper{})
+
+	var b bytes.Buffer
+	data := TestStruct{S: "sv", M: map[string]string{"a": "av"}}
+
+	c.Assert(ex.Execute(templ, &b, data), qt.IsNil)
+	got := b.String()
+
+	c.Assert(got, qt.Contains, "foo")
+	c.Assert(got, qt.Contains, "hello hugo")
+	c.Assert(got, qt.Contains, "Map: av")
+
+}
--- a/tpl/partials/partials.go
+++ b/tpl/partials/partials.go
@@ -139,7 +139,7 @@
 		w = b
 	}
 
-	if err := templ.Execute(w, context); err != nil {
+	if err := ns.deps.Tmpl.Execute(templ, w, context); err != nil {
 		return "", err
 	}
 
--- a/tpl/resources/resources.go
+++ b/tpl/resources/resources.go
@@ -53,7 +53,7 @@
 		integrityClient: integrity.New(deps.ResourceSpec),
 		minifyClient:    minifier.New(deps.ResourceSpec),
 		postcssClient:   postcss.New(deps.ResourceSpec),
-		templatesClient: templates.New(deps.ResourceSpec, deps.TextTmpl),
+		templatesClient: templates.New(deps.ResourceSpec, deps.Tmpl, deps.TextTmpl),
 	}, nil
 }
 
--- a/tpl/template.go
+++ b/tpl/template.go
@@ -14,39 +14,22 @@
 package tpl
 
 import (
-	"fmt"
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
+	"reflect"
 
 	"io"
-	"path/filepath"
 	"regexp"
-	"strings"
-	"time"
 
 	"github.com/gohugoio/hugo/output"
 
-	"github.com/gohugoio/hugo/common/herrors"
-
-	"github.com/gohugoio/hugo/hugofs"
-
-	"github.com/spf13/afero"
-
 	texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
-
-	bp "github.com/gohugoio/hugo/bufferpool"
-	"github.com/gohugoio/hugo/metrics"
-	"github.com/pkg/errors"
 )
 
-var (
-	_ TemplateExecutor     = (*TemplateAdapter)(nil)
-	_ TemplateInfoProvider = (*TemplateAdapter)(nil)
-)
+var _ TemplateInfoProvider = (*TemplateInfo)(nil)
 
-// TemplateHandler manages the collection of templates.
-type TemplateHandler interface {
-	TemplateFinder
+// TemplateManager manages the collection of templates.
+type TemplateManager interface {
+	TemplateHandler
+	TemplateFuncGetter
 	AddTemplate(name, tpl string) error
 	AddLateTemplate(name, tpl string) error
 	LoadTemplates(prefix string) error
@@ -68,6 +51,12 @@
 	TemplateLookupVariant
 }
 
+// TemplateHandler finds and executes templates.
+type TemplateHandler interface {
+	TemplateFinder
+	Execute(t Template, wr io.Writer, data interface{}) error
+}
+
 type TemplateLookup interface {
 	Lookup(name string) (Template, bool)
 }
@@ -87,8 +76,8 @@
 
 // Template is the common interface between text/template and html/template.
 type Template interface {
-	Execute(wr io.Writer, data interface{}) error
 	Name() string
+	Prepare() (*texttemplate.Template, error)
 }
 
 // TemplateInfoProvider provides some contextual information about a template.
@@ -107,30 +96,15 @@
 	TemplateFinder
 }
 
-// TemplateExecutor adds some extras to Template.
-type TemplateExecutor interface {
-	Template
-	ExecuteToString(data interface{}) (string, error)
-	Tree() string
-}
-
 // TemplateDebugger prints some debug info to stdoud.
 type TemplateDebugger interface {
 	Debug()
 }
 
-// TemplateAdapter implements the TemplateExecutor interface.
-type TemplateAdapter struct {
+// TemplateInfo wraps a Template with some additional information.
+type TemplateInfo struct {
 	Template
-	Metrics metrics.Provider
-
 	Info Info
-
-	// The filesystem where the templates are stored.
-	Fs afero.Fs
-
-	// Maps to base template if relevant.
-	NameBaseTemplateName map[string]string
 }
 
 var baseOfRe = regexp.MustCompile("template: (.*?):")
@@ -143,165 +117,11 @@
 	return ""
 }
 
-// Execute executes the current template. The actual execution is performed
-// by the embedded text or html template, but we add an implementation here so
-// we can add a timer for some metrics.
-func (t *TemplateAdapter) Execute(w io.Writer, data interface{}) (execErr error) {
-	defer func() {
-		// Panics in templates are a little bit too common (nil pointers etc.)
-		// See https://github.com/gohugoio/hugo/issues/5327
-		if r := recover(); r != nil {
-			execErr = t.addFileContext(t.Name(), fmt.Errorf(`panic in Execute: %s. See "https://github.com/gohugoio/hugo/issues/5327" for the reason why we cannot provide a better error message for this`, r))
-		}
-	}()
-
-	if t.Metrics != nil {
-		defer t.Metrics.MeasureSince(t.Name(), time.Now())
-	}
-
-	execErr = t.Template.Execute(w, data)
-	if execErr != nil {
-		execErr = t.addFileContext(t.Name(), execErr)
-	}
-
-	return
-}
-
-func (t *TemplateAdapter) TemplateInfo() Info {
+func (t *TemplateInfo) TemplateInfo() Info {
 	return t.Info
 }
 
-// The identifiers may be truncated in the log, e.g.
-// "executing "main" at <$scaled.SRelPermalin...>: can't evaluate field SRelPermalink in type *resource.Image"
-var identifiersRe = regexp.MustCompile(`at \<(.*?)(\.{3})?\>:`)
-
-func (t *TemplateAdapter) extractIdentifiers(line string) []string {
-	m := identifiersRe.FindAllStringSubmatch(line, -1)
-	identifiers := make([]string, len(m))
-	for i := 0; i < len(m); i++ {
-		identifiers[i] = m[i][1]
-	}
-	return identifiers
-}
-
-func (t *TemplateAdapter) addFileContext(name string, inerr error) error {
-	if strings.HasPrefix(t.Name(), "_internal") {
-		return inerr
-	}
-
-	f, realFilename, err := t.fileAndFilename(t.Name())
-	if err != nil {
-		return inerr
-
-	}
-	defer f.Close()
-
-	master, hasMaster := t.NameBaseTemplateName[name]
-
-	ferr := errors.Wrap(inerr, "execute of template failed")
-
-	// Since this can be a composite of multiple template files (single.html + baseof.html etc.)
-	// we potentially need to look in both -- and cannot rely on line number alone.
-	lineMatcher := func(m herrors.LineMatcher) bool {
-		if m.Position.LineNumber != m.LineNumber {
-			return false
-		}
-		if !hasMaster {
-			return true
-		}
-
-		identifiers := t.extractIdentifiers(m.Error.Error())
-
-		for _, id := range identifiers {
-			if strings.Contains(m.Line, id) {
-				return true
-			}
-		}
-		return false
-	}
-
-	fe, ok := herrors.WithFileContext(ferr, realFilename, f, lineMatcher)
-	if ok || !hasMaster {
-		return fe
-	}
-
-	// Try the base template if relevant
-	f, realFilename, err = t.fileAndFilename(master)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	fe, ok = herrors.WithFileContext(ferr, realFilename, f, lineMatcher)
-
-	if !ok {
-		// Return the most specific.
-		return ferr
-
-	}
-	return fe
-
-}
-
-func (t *TemplateAdapter) fileAndFilename(name string) (afero.File, string, error) {
-	fs := t.Fs
-	filename := filepath.FromSlash(name)
-
-	fi, err := fs.Stat(filename)
-	if err != nil {
-		return nil, "", err
-	}
-	fim := fi.(hugofs.FileMetaInfo)
-	meta := fim.Meta()
-
-	f, err := meta.Open()
-	if err != nil {
-		return nil, "", errors.Wrapf(err, "failed to open template file %q:", filename)
-	}
-
-	return f, meta.Filename(), nil
-}
-
-// ExecuteToString executes the current template and returns the result as a
-// string.
-func (t *TemplateAdapter) ExecuteToString(data interface{}) (string, error) {
-	b := bp.GetBuffer()
-	defer bp.PutBuffer(b)
-	if err := t.Execute(b, data); err != nil {
-		return "", err
-	}
-	return b.String(), nil
-}
-
-// Tree returns the template Parse tree as a string.
-// Note: this isn't safe for parallel execution on the same template
-// vs Lookup and Execute.
-func (t *TemplateAdapter) Tree() string {
-	var tree *parse.Tree
-	switch tt := t.Template.(type) {
-	case *template.Template:
-		tree = tt.Tree
-	case *texttemplate.Template:
-		tree = tt.Tree
-	default:
-		panic("Unknown template")
-	}
-
-	if tree == nil || tree.Root == nil {
-		return ""
-	}
-	s := tree.Root.String()
-
-	return s
-}
-
-// TemplateFuncsGetter allows to get a map of functions.
-type TemplateFuncsGetter interface {
-	GetFuncs() map[string]interface{}
-}
-
-// TemplateTestMocker adds a way to override some template funcs during tests.
-// The interface is named so it's not used in regular application code.
-type TemplateTestMocker interface {
-	SetFuncs(funcMap map[string]interface{})
+// TemplateFuncGetter allows to find a template func by name.
+type TemplateFuncGetter interface {
+	GetFunc(name string) (reflect.Value, bool)
 }
--- a/tpl/tplimpl/embedded/templates.autogen.go
+++ b/tpl/tplimpl/embedded/templates.autogen.go
@@ -87,6 +87,7 @@
 	{{ end }}
 </sitemapindex>
 `},
+	{`alias.html`, `<!DOCTYPE html><html><head><title>{{ .Permalink }}</title><link rel="canonical" href="{{ .Permalink }}"/><meta name="robots" content="noindex"><meta charset="utf-8" /><meta http-equiv="refresh" content="0; url={{ .Permalink }}" /></head></html>`},
 	{`disqus.html`, `{{- $pc := .Site.Config.Privacy.Disqus -}}
 {{- if not $pc.Disable -}}
 {{ if .Site.DisqusShortname }}<div id="disqus_thread"></div>
--- /dev/null
+++ b/tpl/tplimpl/embedded/templates/alias.html
@@ -1,0 +1,1 @@
+<!DOCTYPE html><html><head><title>{{ .Permalink }}</title><link rel="canonical" href="{{ .Permalink }}"/><meta name="robots" content="noindex"><meta charset="utf-8" /><meta http-equiv="refresh" content="0; url={{ .Permalink }}" /></head></html>
\ No newline at end of file
--- a/tpl/tplimpl/shortcodes.go
+++ b/tpl/tplimpl/shortcodes.go
@@ -61,11 +61,6 @@
 	})
 }
 
-// Get the most specific template given a full name, e.g  gtag.no.amp.html.
-func (s *shortcodeTemplates) fromName(name string) (shortcodeVariant, bool) {
-	return s.fromVariantsSlice(templateVariants(name))
-}
-
 func (s *shortcodeTemplates) fromVariantsSlice(variants []string) (shortcodeVariant, bool) {
 	var (
 		bestMatch       shortcodeVariant
--- a/tpl/tplimpl/template.go
+++ b/tpl/tplimpl/template.go
@@ -15,7 +15,13 @@
 
 import (
 	"fmt"
+	"io"
+	"reflect"
+	"regexp"
+	"time"
 
+	"github.com/gohugoio/hugo/common/herrors"
+
 	"strings"
 
 	template "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
@@ -45,121 +51,198 @@
 )
 
 var (
-	_ tpl.TemplateHandler       = (*templateHandler)(nil)
-	_ tpl.TemplateDebugger      = (*templateHandler)(nil)
-	_ tpl.TemplateFuncsGetter   = (*templateHandler)(nil)
-	_ tpl.TemplateTestMocker    = (*templateHandler)(nil)
-	_ tpl.TemplateFinder        = (*htmlTemplates)(nil)
-	_ tpl.TemplateFinder        = (*textTemplates)(nil)
-	_ templateLoader            = (*htmlTemplates)(nil)
-	_ templateLoader            = (*textTemplates)(nil)
-	_ templateFuncsterTemplater = (*htmlTemplates)(nil)
-	_ templateFuncsterTemplater = (*textTemplates)(nil)
+	_ tpl.TemplateManager    = (*templateHandler)(nil)
+	_ tpl.TemplateHandler    = (*templateHandler)(nil)
+	_ tpl.TemplateDebugger   = (*templateHandler)(nil)
+	_ tpl.TemplateFuncGetter = (*templateHandler)(nil)
+	_ tpl.TemplateFinder     = (*htmlTemplates)(nil)
+	_ tpl.TemplateFinder     = (*textTemplates)(nil)
+	_ templateLoader         = (*htmlTemplates)(nil)
+	_ templateLoader         = (*textTemplates)(nil)
 )
 
-type templateErr struct {
-	name string
-	err  error
-}
+const (
+	shortcodesPathPrefix = "shortcodes/"
+	internalPathPrefix   = "_internal/"
+)
 
-type templateLoader interface {
-	handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error
-	addTemplate(name, tpl string) (*templateContext, error)
-	addLateTemplate(name, tpl string) error
-}
+// The identifiers may be truncated in the log, e.g.
+// "executing "main" at <$scaled.SRelPermalin...>: can't evaluate field SRelPermalink in type *resource.Image"
+var identifiersRe = regexp.MustCompile(`at \<(.*?)(\.{3})?\>:`)
 
-type templateFuncsterTemplater interface {
-	templateFuncsterSetter
-	tpl.TemplateFinder
-	setFuncs(funcMap map[string]interface{})
+var embeddedTemplatesAliases = map[string][]string{
+	"shortcodes/twitter.html": {"shortcodes/tweet.html"},
 }
 
-type templateFuncsterSetter interface {
-	setTemplateFuncster(f *templateFuncster)
-}
+const baseFileBase = "baseof"
 
-// templateHandler holds the templates in play.
-// It implements the templateLoader and tpl.TemplateHandler interfaces.
-type templateHandler struct {
-	mu sync.Mutex
+func newTemplateAdapter(deps *deps.Deps) *templateHandler {
 
-	// shortcodes maps shortcode name to template variants
-	// (language, output format etc.) of that shortcode.
-	shortcodes map[string]*shortcodeTemplates
+	common := &templatesCommon{
+		nameBaseTemplateName: make(map[string]string),
+		transformNotFound:    make(map[string]bool),
+	}
 
-	// templateInfo maps template name to some additional information about that template.
-	// Note that for shortcodes that same information is embedded in the
-	// shortcodeTemplates type.
-	templateInfo map[string]tpl.Info
+	htmlT := &htmlTemplates{
+		t:               template.New(""),
+		overlays:        make(map[string]*template.Template),
+		templatesCommon: common,
+	}
 
-	// text holds all the pure text templates.
-	text *textTemplates
-	html *htmlTemplates
+	textT := &textTemplates{
+		textTemplate:    &textTemplate{t: texttemplate.New("")},
+		standalone:      &textTemplate{t: texttemplate.New("")},
+		overlays:        make(map[string]*texttemplate.Template),
+		templatesCommon: common,
+	}
 
-	errors []*templateErr
+	h := &templateHandler{
+		Deps:      deps,
+		layoutsFs: deps.BaseFs.Layouts.Fs,
+		templateHandlerCommon: &templateHandlerCommon{
+			shortcodes:   make(map[string]*shortcodeTemplates),
+			templateInfo: make(map[string]tpl.Info),
+			html:         htmlT,
+			text:         textT,
+		},
+	}
 
-	// This is the filesystem to load the templates from. All the templates are
-	// stored in the root of this filesystem.
-	layoutsFs afero.Fs
+	common.handler = h
 
-	*deps.Deps
+	return h
+
 }
 
-const (
-	shortcodesPathPrefix = "shortcodes/"
-	internalPathPrefix   = "_internal/"
-)
+type htmlTemplates struct {
+	*templatesCommon
 
-// resolves _internal/shortcodes/param.html => param.html etc.
-func templateBaseName(typ templateType, name string) string {
-	name = strings.TrimPrefix(name, internalPathPrefix)
-	switch typ {
-	case templateShortcode:
-		return strings.TrimPrefix(name, shortcodesPathPrefix)
-	default:
-		panic("not implemented")
+	t *template.Template
+
+	// This looks, and is, strange.
+	// The clone is used by non-renderable content pages, and these need to be
+	// re-parsed on content change, and to avoid the
+	// "cannot Parse after Execute" error, we need to re-clone it from the original clone.
+	clone      *template.Template
+	cloneClone *template.Template
+
+	// a separate storage for the overlays created from cloned master templates.
+	// note: No mutex protection, so we add these in one Go routine, then just read.
+	overlays map[string]*template.Template
+}
+
+func (t *htmlTemplates) Lookup(name string) (tpl.Template, bool) {
+	templ := t.lookup(name)
+	if templ == nil {
+		return nil, false
 	}
 
+	return templ, true
 }
 
-func (t *templateHandler) addShortcodeVariant(name string, info tpl.Info, templ tpl.Template) {
-	base := templateBaseName(templateShortcode, name)
+func (t *htmlTemplates) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
+	return t.handler.LookupVariant(name, variants)
+}
 
-	shortcodename, variants := templateNameAndVariants(base)
+func (t *htmlTemplates) addLateTemplate(name, tpl string) error {
+	_, err := t.addTemplateIn(t.clone, name, tpl)
+	return err
+}
 
-	templs, found := t.shortcodes[shortcodename]
-	if !found {
-		templs = &shortcodeTemplates{}
-		t.shortcodes[shortcodename] = templs
+func (t *htmlTemplates) addTemplate(name, tpl string) (*templateContext, error) {
+	return t.addTemplateIn(t.t, name, tpl)
+}
+
+func (t *htmlTemplates) addTemplateIn(tt *template.Template, name, tpl string) (*templateContext, error) {
+	templ, err := tt.New(name).Parse(tpl)
+	if err != nil {
+		return nil, err
 	}
 
-	sv := shortcodeVariant{variants: variants, info: info, templ: templ}
+	typ := resolveTemplateType(name)
 
-	i := templs.indexOf(variants)
+	c, err := applyTemplateTransformersToHMLTTemplate(typ, templ)
+	if err != nil {
+		return nil, err
+	}
 
-	if i != -1 {
-		// Only replace if it's an override of an internal template.
-		if !isInternal(name) {
-			templs.variants[i] = sv
-		}
+	for k := range c.notFound {
+		t.transformNotFound[k] = true
+	}
+
+	if typ == templateShortcode {
+		t.handler.addShortcodeVariant(name, c.Info, templ)
 	} else {
-		templs.variants = append(templs.variants, sv)
+		t.handler.templateInfo[name] = c.Info
 	}
+
+	return c, nil
 }
 
-func (t *templateHandler) wrapTextTemplate(tt *textTemplate) tpl.TemplateParseFinder {
-	return struct {
-		tpl.TemplateParser
-		tpl.TemplateLookup
-		tpl.TemplateLookupVariant
-	}{
-		tt,
-		tt,
-		new(nopLookupVariant),
+func (t *htmlTemplates) handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error {
+
+	masterTpl := t.lookup(masterFilename)
+
+	if masterTpl == nil {
+		templ, err := onMissing(masterFilename)
+		if err != nil {
+			return err
+		}
+
+		masterTpl, err = t.t.New(overlayFilename).Parse(templ.template)
+		if err != nil {
+			return templ.errWithFileContext("parse master failed", err)
+		}
 	}
 
+	templ, err := onMissing(overlayFilename)
+	if err != nil {
+		return err
+	}
+
+	overlayTpl, err := template.Must(masterTpl.Clone()).Parse(templ.template)
+	if err != nil {
+		return templ.errWithFileContext("parse failed", err)
+	}
+
+	// The extra lookup is a workaround, see
+	// * https://github.com/golang/go/issues/16101
+	// * https://github.com/gohugoio/hugo/issues/2549
+	overlayTpl = overlayTpl.Lookup(overlayTpl.Name())
+	if _, err := applyTemplateTransformersToHMLTTemplate(templateUndefined, overlayTpl); err != nil {
+		return err
+	}
+
+	t.overlays[name] = overlayTpl
+	t.nameBaseTemplateName[name] = masterFilename
+
+	return err
+
 }
 
+func (t *htmlTemplates) lookup(name string) *template.Template {
+	// Need to check in the overlay registry first as it will also be found below.
+	if t.overlays != nil {
+		if templ, ok := t.overlays[name]; ok {
+			return templ
+		}
+	}
+
+	if templ := t.t.Lookup(name); templ != nil {
+		return templ
+	}
+
+	if t.clone != nil {
+		return t.clone.Lookup(name)
+	}
+
+	return nil
+}
+
+func (t htmlTemplates) withNewHandler(h *templateHandler) *htmlTemplates {
+	t.templatesCommon = t.templatesCommon.withNewHandler(h)
+	return &t
+}
+
 type nopLookupVariant int
 
 func (l nopLookupVariant) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
@@ -166,15 +249,81 @@
 	return nil, false, false
 }
 
+// templateHandler holds the templates in play.
+// It implements the templateLoader and tpl.TemplateHandler interfaces.
+// There is one templateHandler created per Site.
+type templateHandler struct {
+	executor texttemplate.Executer
+	funcs    map[string]reflect.Value
+
+	// This is the filesystem to load the templates from. All the templates are
+	// stored in the root of this filesystem.
+	layoutsFs afero.Fs
+
+	*deps.Deps
+
+	*templateHandlerCommon
+}
+
+// AddLateTemplate is used to add a template late, i.e. after the
+// regular templates have started its execution.
+func (t *templateHandler) AddLateTemplate(name, tpl string) error {
+	h := t.getTemplateHandler(name)
+	if err := h.addLateTemplate(name, tpl); err != nil {
+		return err
+	}
+	return nil
+}
+
+// AddTemplate parses and adds a template to the collection.
+// Templates with name prefixed with "_text" will be handled as plain
+// text templates.
+// TODO(bep) clean up these addTemplate variants
+func (t *templateHandler) AddTemplate(name, tpl string) error {
+	h := t.getTemplateHandler(name)
+	_, err := h.addTemplate(name, tpl)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func (t *templateHandler) Debug() {
 	fmt.Println("HTML templates:\n", t.html.t.DefinedTemplates())
 	fmt.Println("\n\nText templates:\n", t.text.t.DefinedTemplates())
 }
 
+func (t *templateHandler) Execute(templ tpl.Template, wr io.Writer, data interface{}) error {
+	if t.Metrics != nil {
+		defer t.Metrics.MeasureSince(templ.Name(), time.Now())
+	}
+
+	execErr := t.executor.Execute(templ, wr, data)
+	if execErr != nil {
+		execErr = t.addFileContext(templ.Name(), execErr)
+	}
+
+	return execErr
+
+}
+
+func (t *templateHandler) GetFunc(name string) (reflect.Value, bool) {
+	v, found := t.funcs[name]
+	return v, found
+
+}
+
+// LoadTemplates loads the templates from the layouts filesystem.
+// A prefix can be given to indicate a template namespace to load the templates
+// into, i.e. "_internal" etc.
+func (t *templateHandler) LoadTemplates(prefix string) error {
+	return t.loadTemplates(prefix)
+
+}
+
 // Lookup tries to find a template with the given name in both template
 // collections: First HTML, then the plain text template collection.
 func (t *templateHandler) Lookup(name string) (tpl.Template, bool) {
-
 	if strings.HasPrefix(name, textTmplNamePrefix) {
 		// The caller has explicitly asked for a text template, so only look
 		// in the text template collection.
@@ -193,18 +342,6 @@
 
 }
 
-func (t *templateHandler) applyTemplateInfo(templ tpl.Template, found bool) (tpl.Template, bool) {
-	if adapter, ok := templ.(*tpl.TemplateAdapter); ok {
-		if adapter.Info.IsZero() {
-			if info, found := t.templateInfo[templ.Name()]; found {
-				adapter.Info = info
-			}
-		}
-	}
-
-	return templ, found
-}
-
 // This currently only applies to shortcodes and what we get here is the
 // shortcode name.
 func (t *templateHandler) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
@@ -221,384 +358,351 @@
 
 	more := len(s.variants) > 1
 
-	return &tpl.TemplateAdapter{
-		Template:             sv.templ,
-		Info:                 sv.info,
-		Metrics:              t.Deps.Metrics,
-		Fs:                   t.layoutsFs,
-		NameBaseTemplateName: t.html.nameBaseTemplateName}, true, more
+	return &tpl.TemplateInfo{
+		Template: sv.templ,
+		Info:     sv.info,
+	}, true, more
 
 }
 
-func (t *textTemplates) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
-	return t.handler.LookupVariant(name, variants)
-}
+// MarkReady marks the templates as "ready for execution". No changes allowed
+// after this is set.
+// TODO(bep) if this proves to be resource heavy, we could detect
+// earlier if we really need this, or make it lazy.
+func (t *templateHandler) MarkReady() error {
+	if err := t.postTransform(); err != nil {
+		return err
+	}
 
-func (t *htmlTemplates) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
-	return t.handler.LookupVariant(name, variants)
+	if t.html.clone == nil {
+		t.html.clone = template.Must(t.html.t.Clone())
+		t.html.cloneClone = template.Must(t.html.clone.Clone())
+	}
+	if t.text.clone == nil {
+		t.text.clone = texttemplate.Must(t.text.t.Clone())
+		t.text.cloneClone = texttemplate.Must(t.text.clone.Clone())
+	}
+
+	return nil
 }
 
-func (t *templateHandler) lookupTemplate(in interface{}) tpl.Template {
-	switch templ := in.(type) {
-	case *texttemplate.Template:
-		return t.text.lookup(templ.Name())
-	case *template.Template:
-		return t.html.lookup(templ.Name())
+// RebuildClone rebuilds the cloned templates. Used for live-reloads.
+func (t *templateHandler) RebuildClone() {
+	if t.html != nil && t.html.cloneClone != nil {
+		t.html.clone = template.Must(t.html.cloneClone.Clone())
 	}
-
-	panic(fmt.Sprintf("%T is not a template", in))
+	if t.text != nil && t.text.cloneClone != nil {
+		t.text.clone = texttemplate.Must(t.text.cloneClone.Clone())
+	}
 }
 
-func (t *templateHandler) setFuncMapInTemplate(in interface{}, funcs map[string]interface{}) {
-	switch templ := in.(type) {
-	case *texttemplate.Template:
-		templ.Funcs(funcs)
-		return
-	case *template.Template:
-		templ.Funcs(funcs)
-		return
+func (h *templateHandler) initTemplateExecuter() {
+	exec, funcs := newTemplateExecuter(h.Deps)
+	h.executor = exec
+	h.funcs = funcs
+	funcMap := make(map[string]interface{})
+	for k, v := range funcs {
+		funcMap[k] = v.Interface()
 	}
 
-	panic(fmt.Sprintf("%T is not a template", in))
+	// Note that these funcs are not the ones getting called
+	// on execution, but they are needed at parse time.
+	h.text.textTemplate.t.Funcs(funcMap)
+	h.text.standalone.t.Funcs(funcMap)
+	h.html.t.Funcs(funcMap)
 }
 
-func (t *templateHandler) clone(d *deps.Deps) *templateHandler {
-	c := &templateHandler{
-		Deps:         d,
-		layoutsFs:    d.BaseFs.Layouts.Fs,
-		shortcodes:   make(map[string]*shortcodeTemplates),
-		templateInfo: t.templateInfo,
-		html:         &htmlTemplates{t: template.Must(t.html.t.Clone()), overlays: make(map[string]*template.Template), templatesCommon: t.html.templatesCommon},
-		text: &textTemplates{
-			textTemplate: &textTemplate{t: texttemplate.Must(t.text.t.Clone())},
-			standalone:   &textTemplate{t: texttemplate.New("")},
-			overlays:     make(map[string]*texttemplate.Template), templatesCommon: t.text.templatesCommon},
-		errors: make([]*templateErr, 0),
+func (t *templateHandler) getTemplateHandler(name string) templateLoader {
+	if strings.HasPrefix(name, textTmplNamePrefix) {
+		return t.text
 	}
+	return t.html
+}
 
-	for k, v := range t.shortcodes {
-		other := *v
-		variantsc := make([]shortcodeVariant, len(v.variants))
-		for i, variant := range v.variants {
-			variantsc[i] = shortcodeVariant{
-				info:     variant.info,
-				variants: variant.variants,
-				templ:    c.lookupTemplate(variant.templ),
-			}
-		}
-		other.variants = variantsc
-		c.shortcodes[k] = &other
+func (t *templateHandler) addFileContext(name string, inerr error) error {
+	if strings.HasPrefix(name, "_internal") {
+		return inerr
 	}
 
-	d.Tmpl = c
-	d.TextTmpl = c.wrapTextTemplate(c.text.standalone)
+	f, realFilename, err := t.fileAndFilename(name)
+	if err != nil {
+		return inerr
 
-	c.initFuncs()
-
-	for k, v := range t.html.overlays {
-		vc := template.Must(v.Clone())
-		// The extra lookup is a workaround, see
-		// * https://github.com/golang/go/issues/16101
-		// * https://github.com/gohugoio/hugo/issues/2549
-		vc = vc.Lookup(vc.Name())
-		vc.Funcs(c.html.funcster.funcMap)
-		c.html.overlays[k] = vc
 	}
+	defer f.Close()
 
-	for k, v := range t.text.overlays {
-		vc := texttemplate.Must(v.Clone())
-		vc = vc.Lookup(vc.Name())
-		vc.Funcs(texttemplate.FuncMap(c.text.funcster.funcMap))
-		c.text.overlays[k] = vc
-	}
+	master, hasMaster := t.html.nameBaseTemplateName[name]
 
-	return c
+	ferr := errors.Wrap(inerr, "execute of template failed")
 
-}
+	// Since this can be a composite of multiple template files (single.html + baseof.html etc.)
+	// we potentially need to look in both -- and cannot rely on line number alone.
+	lineMatcher := func(m herrors.LineMatcher) bool {
+		if m.Position.LineNumber != m.LineNumber {
+			return false
+		}
+		if !hasMaster {
+			return true
+		}
 
-func newTemplateAdapter(deps *deps.Deps) *templateHandler {
-	common := &templatesCommon{
-		nameBaseTemplateName: make(map[string]string),
-		transformNotFound:    make(map[string]bool),
+		identifiers := t.extractIdentifiers(m.Error.Error())
+
+		for _, id := range identifiers {
+			if strings.Contains(m.Line, id) {
+				return true
+			}
+		}
+		return false
 	}
 
-	htmlT := &htmlTemplates{
-		t:               template.New(""),
-		overlays:        make(map[string]*template.Template),
-		templatesCommon: common,
+	fe, ok := herrors.WithFileContext(ferr, realFilename, f, lineMatcher)
+	if ok || !hasMaster {
+		return fe
 	}
-	textT := &textTemplates{
-		textTemplate:    &textTemplate{t: texttemplate.New("")},
-		standalone:      &textTemplate{t: texttemplate.New("")},
-		overlays:        make(map[string]*texttemplate.Template),
-		templatesCommon: common,
+
+	// Try the base template if relevant
+	f, realFilename, err = t.fileAndFilename(master)
+	if err != nil {
+		return err
 	}
-	h := &templateHandler{
-		Deps:         deps,
-		layoutsFs:    deps.BaseFs.Layouts.Fs,
-		shortcodes:   make(map[string]*shortcodeTemplates),
-		templateInfo: make(map[string]tpl.Info),
-		html:         htmlT,
-		text:         textT,
-		errors:       make([]*templateErr, 0),
-	}
+	defer f.Close()
 
-	common.handler = h
+	fe, ok = herrors.WithFileContext(ferr, realFilename, f, lineMatcher)
 
-	return h
+	if !ok {
+		// Return the most specific.
+		return ferr
 
+	}
+	return fe
+
 }
 
-// Shared by both HTML and text templates.
-type templatesCommon struct {
-	handler  *templateHandler
-	funcster *templateFuncster
+func (t *templateHandler) addInternalTemplate(name, tpl string) error {
+	return t.AddTemplate("_internal/"+name, tpl)
+}
 
-	// Used to get proper filenames in errors
-	nameBaseTemplateName map[string]string
+func (t *templateHandler) addShortcodeVariant(name string, info tpl.Info, templ tpl.Template) {
+	base := templateBaseName(templateShortcode, name)
 
-	// Holds names of the templates not found during the first AST transformation
-	// pass.
-	transformNotFound map[string]bool
-}
-type htmlTemplates struct {
-	mu sync.RWMutex
+	shortcodename, variants := templateNameAndVariants(base)
 
-	*templatesCommon
+	templs, found := t.shortcodes[shortcodename]
+	if !found {
+		templs = &shortcodeTemplates{}
+		t.shortcodes[shortcodename] = templs
+	}
 
-	t *template.Template
+	sv := shortcodeVariant{variants: variants, info: info, templ: templ}
 
-	// This looks, and is, strange.
-	// The clone is used by non-renderable content pages, and these need to be
-	// re-parsed on content change, and to avoid the
-	// "cannot Parse after Execute" error, we need to re-clone it from the original clone.
-	clone      *template.Template
-	cloneClone *template.Template
+	i := templs.indexOf(variants)
 
-	// a separate storage for the overlays created from cloned master templates.
-	// note: No mutex protection, so we add these in one Go routine, then just read.
-	overlays map[string]*template.Template
+	if i != -1 {
+		// Only replace if it's an override of an internal template.
+		if !isInternal(name) {
+			templs.variants[i] = sv
+		}
+	} else {
+		templs.variants = append(templs.variants, sv)
+	}
 }
 
-func (t *htmlTemplates) setTemplateFuncster(f *templateFuncster) {
-	t.funcster = f
-}
+func (t *templateHandler) addTemplateFile(name, baseTemplatePath, path string) error {
+	t.checkState()
 
-func (t *htmlTemplates) Lookup(name string) (tpl.Template, bool) {
-	templ := t.lookup(name)
-	if templ == nil {
-		return nil, false
-	}
+	t.Log.DEBUG.Printf("Add template file: name %q, baseTemplatePath %q, path %q", name, baseTemplatePath, path)
 
-	return &tpl.TemplateAdapter{Template: templ, Metrics: t.funcster.Deps.Metrics, Fs: t.handler.layoutsFs, NameBaseTemplateName: t.nameBaseTemplateName}, true
-}
+	getTemplate := func(filename string) (templateInfo, error) {
+		fs := t.Layouts.Fs
+		b, err := afero.ReadFile(fs, filename)
+		if err != nil {
+			return templateInfo{filename: filename, fs: fs}, err
+		}
 
-func (t *htmlTemplates) lookup(name string) *template.Template {
-	t.mu.RLock()
-	defer t.mu.RUnlock()
+		s := removeLeadingBOM(string(b))
 
-	// Need to check in the overlay registry first as it will also be found below.
-	if t.overlays != nil {
-		if templ, ok := t.overlays[name]; ok {
-			return templ
+		realFilename := filename
+		if fi, err := fs.Stat(filename); err == nil {
+			if fim, ok := fi.(hugofs.FileMetaInfo); ok {
+				realFilename = fim.Meta().Filename()
+			}
 		}
-	}
 
-	if templ := t.t.Lookup(name); templ != nil {
-		return templ
+		return templateInfo{template: s, filename: filename, realFilename: realFilename, fs: fs}, nil
 	}
 
-	if t.clone != nil {
-		return t.clone.Lookup(name)
-	}
+	// get the suffix and switch on that
+	ext := filepath.Ext(path)
+	switch ext {
+	case ".amber":
+		helpers.Deprecated("Amber templates are no longer supported.", "Use Go templates or a Hugo version <= 0.60.", true)
+		return nil
+	case ".ace":
+		helpers.Deprecated("ACE templates are no longer supported.", "Use Go templates or a Hugo version <= 0.60.", true)
+		return nil
+	default:
 
-	return nil
-}
+		if baseTemplatePath != "" {
+			return t.handleMaster(name, path, baseTemplatePath, getTemplate)
+		}
 
-func (t *textTemplates) setTemplateFuncster(f *templateFuncster) {
-	t.funcster = f
-}
+		templ, err := getTemplate(path)
 
-type textTemplates struct {
-	*templatesCommon
-	*textTemplate
-	standalone *textTemplate
-	clone      *texttemplate.Template
-	cloneClone *texttemplate.Template
+		if err != nil {
+			return err
+		}
 
-	overlays map[string]*texttemplate.Template
-}
-
-func (t *textTemplates) Lookup(name string) (tpl.Template, bool) {
-	templ := t.lookup(name)
-	if templ == nil {
-		return nil, false
+		err = t.AddTemplate(name, templ.template)
+		if err != nil {
+			return templ.errWithFileContext("parse failed", err)
+		}
+		return nil
 	}
-	return &tpl.TemplateAdapter{Template: templ, Metrics: t.funcster.Deps.Metrics, Fs: t.handler.layoutsFs, NameBaseTemplateName: t.nameBaseTemplateName}, true
 }
 
-func (t *textTemplates) lookup(name string) *texttemplate.Template {
-
-	// Need to check in the overlay registry first as it will also be found below.
-	if t.overlays != nil {
-		if templ, ok := t.overlays[name]; ok {
-			return templ
+func (t *templateHandler) applyTemplateInfo(templ tpl.Template, found bool) (tpl.Template, bool) {
+	if adapter, ok := templ.(*tpl.TemplateInfo); ok {
+		if adapter.Info.IsZero() {
+			if info, found := t.templateInfo[templ.Name()]; found {
+				adapter.Info = info
+			}
 		}
+	} else if templ != nil {
+		if info, found := t.templateInfo[templ.Name()]; found {
+			return &tpl.TemplateInfo{
+				Template: templ,
+				Info:     info,
+			}, true
+		}
 	}
 
-	if templ := t.t.Lookup(name); templ != nil {
-		return templ
-	}
+	return templ, found
+}
 
-	if t.clone != nil {
-		return t.clone.Lookup(name)
+func (t *templateHandler) checkState() {
+	if t.html.clone != nil || t.text.clone != nil {
+		panic("template is cloned and cannot be modfified")
 	}
-
-	return nil
 }
 
-func (t *templateHandler) setFuncs(funcMap map[string]interface{}) {
-	t.html.setFuncs(funcMap)
-	t.text.setFuncs(funcMap)
-	t.setFuncMapInTemplate(t.text.standalone.t, funcMap)
-}
+func (t *templateHandler) clone(d *deps.Deps) *templateHandler {
+	c := &templateHandler{
+		Deps:      d,
+		layoutsFs: d.BaseFs.Layouts.Fs,
+	}
 
-// SetFuncs replaces the funcs in the func maps with new definitions.
-// This is only used in tests.
-func (t *templateHandler) SetFuncs(funcMap map[string]interface{}) {
-	t.setFuncs(funcMap)
-}
+	c.templateHandlerCommon = t.templateHandlerCommon.withNewHandler(c)
+	d.Tmpl = c
+	d.TextTmpl = c.wrapTextTemplate(c.text.standalone)
+	c.executor, c.funcs = newTemplateExecuter(d)
 
-func (t *templateHandler) GetFuncs() map[string]interface{} {
-	return t.html.funcster.funcMap
-}
+	return c
 
-func (t *htmlTemplates) setFuncs(funcMap map[string]interface{}) {
-	t.t.Funcs(funcMap)
 }
 
-func (t *textTemplates) setFuncs(funcMap map[string]interface{}) {
-	t.t.Funcs(funcMap)
+func (t *templateHandler) extractIdentifiers(line string) []string {
+	m := identifiersRe.FindAllStringSubmatch(line, -1)
+	identifiers := make([]string, len(m))
+	for i := 0; i < len(m); i++ {
+		identifiers[i] = m[i][1]
+	}
+	return identifiers
 }
 
-// LoadTemplates loads the templates from the layouts filesystem.
-// A prefix can be given to indicate a template namespace to load the templates
-// into, i.e. "_internal" etc.
-func (t *templateHandler) LoadTemplates(prefix string) error {
-	return t.loadTemplates(prefix)
+func (t *templateHandler) fileAndFilename(name string) (afero.File, string, error) {
+	fs := t.layoutsFs
+	filename := filepath.FromSlash(name)
 
-}
-
-func (t *htmlTemplates) addTemplateIn(tt *template.Template, name, tpl string) (*templateContext, error) {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-
-	templ, err := tt.New(name).Parse(tpl)
+	fi, err := fs.Stat(filename)
 	if err != nil {
-		return nil, err
+		return nil, "", err
 	}
+	fim := fi.(hugofs.FileMetaInfo)
+	meta := fim.Meta()
 
-	typ := resolveTemplateType(name)
-
-	c, err := applyTemplateTransformersToHMLTTemplate(typ, templ)
+	f, err := meta.Open()
 	if err != nil {
-		return nil, err
+		return nil, "", errors.Wrapf(err, "failed to open template file %q:", filename)
 	}
 
-	for k := range c.notFound {
-		t.transformNotFound[k] = true
-	}
-
-	if typ == templateShortcode {
-		t.handler.addShortcodeVariant(name, c.Info, templ)
-	} else {
-		t.handler.templateInfo[name] = c.Info
-	}
-
-	return c, nil
+	return f, meta.Filename(), nil
 }
 
-func (t *htmlTemplates) addTemplate(name, tpl string) (*templateContext, error) {
-	return t.addTemplateIn(t.t, name, tpl)
+func (t *templateHandler) handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error {
+	h := t.getTemplateHandler(name)
+	return h.handleMaster(name, overlayFilename, masterFilename, onMissing)
 }
 
-func (t *htmlTemplates) addLateTemplate(name, tpl string) error {
-	_, err := t.addTemplateIn(t.clone, name, tpl)
-	return err
-}
+func (t *templateHandler) loadEmbedded() error {
+	for _, kv := range embedded.EmbeddedTemplates {
+		name, templ := kv[0], kv[1]
+		if err := t.addInternalTemplate(name, templ); err != nil {
+			return err
+		}
+		if aliases, found := embeddedTemplatesAliases[name]; found {
+			for _, alias := range aliases {
+				if err := t.addInternalTemplate(alias, templ); err != nil {
+					return err
+				}
+			}
 
-type textTemplate struct {
-	mu sync.RWMutex
-	t  *texttemplate.Template
-}
+		}
+	}
 
-func (t *textTemplate) Parse(name, tpl string) (tpl.Template, error) {
-	return t.parseIn(t.t, name, tpl)
+	return nil
+
 }
 
-func (t *textTemplate) Lookup(name string) (tpl.Template, bool) {
-	t.mu.RLock()
-	defer t.mu.RUnlock()
+func (t *templateHandler) loadTemplates(prefix string) error {
 
-	tpl := t.t.Lookup(name)
-	return tpl, tpl != nil
-}
+	walker := func(path string, fi hugofs.FileMetaInfo, err error) error {
+		if err != nil || fi.IsDir() {
+			return err
+		}
 
-func (t *textTemplate) parseIn(tt *texttemplate.Template, name, tpl string) (*texttemplate.Template, error) {
-	t.mu.Lock()
-	defer t.mu.Unlock()
+		if isDotFile(path) || isBackupFile(path) || isBaseTemplate(path) {
+			return nil
+		}
 
-	templ, err := tt.New(name).Parse(tpl)
-	if err != nil {
-		return nil, err
-	}
+		workingDir := t.PathSpec.WorkingDir
 
-	if _, err := applyTemplateTransformersToTextTemplate(templateUndefined, templ); err != nil {
-		return nil, err
-	}
-	return templ, nil
-}
+		descriptor := output.TemplateLookupDescriptor{
+			WorkingDir:    workingDir,
+			RelPath:       path,
+			Prefix:        prefix,
+			OutputFormats: t.OutputFormatsConfig,
+			FileExists: func(filename string) (bool, error) {
+				return helpers.Exists(filename, t.Layouts.Fs)
+			},
+			ContainsAny: func(filename string, subslices [][]byte) (bool, error) {
+				return helpers.FileContainsAny(filename, subslices, t.Layouts.Fs)
+			},
+		}
 
-func (t *textTemplates) addTemplateIn(tt *texttemplate.Template, name, tpl string) (*templateContext, error) {
-	name = strings.TrimPrefix(name, textTmplNamePrefix)
-	templ, err := t.parseIn(tt, name, tpl)
-	if err != nil {
-		return nil, err
-	}
+		tplID, err := output.CreateTemplateNames(descriptor)
+		if err != nil {
+			t.Log.ERROR.Printf("Failed to resolve template in path %q: %s", path, err)
+			return nil
+		}
 
-	typ := resolveTemplateType(name)
+		if err := t.addTemplateFile(tplID.Name, tplID.MasterFilename, tplID.OverlayFilename); err != nil {
+			return err
+		}
 
-	c, err := applyTemplateTransformersToTextTemplate(typ, templ)
-	if err != nil {
-		return nil, err
+		return nil
 	}
 
-	for k := range c.notFound {
-		t.transformNotFound[k] = true
+	if err := helpers.SymbolicWalk(t.Layouts.Fs, "", walker); err != nil {
+		if !os.IsNotExist(err) {
+			return err
+		}
+		return nil
 	}
 
-	if typ == templateShortcode {
-		t.handler.addShortcodeVariant(name, c.Info, templ)
-	} else {
-		t.handler.templateInfo[name] = c.Info
-	}
+	return nil
 
-	return c, nil
 }
 
-func (t *textTemplates) addTemplate(name, tpl string) (*templateContext, error) {
-	return t.addTemplateIn(t.t, name, tpl)
-}
-
-func (t *textTemplates) addLateTemplate(name, tpl string) error {
-	_, err := t.addTemplateIn(t.clone, name, tpl)
-	return err
-}
-
-func (t *templateHandler) addTemplate(name, tpl string) error {
-	return t.AddTemplate(name, tpl)
-}
-
 func (t *templateHandler) postTransform() error {
 	if len(t.html.transformNotFound) == 0 && len(t.text.transformNotFound) == 0 {
 		return nil
@@ -644,189 +748,151 @@
 	return nil
 }
 
-func (t *templateHandler) addLateTemplate(name, tpl string) error {
-	return t.AddLateTemplate(name, tpl)
-}
-
-// AddLateTemplate is used to add a template late, i.e. after the
-// regular templates have started its execution.
-func (t *templateHandler) AddLateTemplate(name, tpl string) error {
-	h := t.getTemplateHandler(name)
-	if err := h.addLateTemplate(name, tpl); err != nil {
-		return err
+func (t *templateHandler) wrapTextTemplate(tt *textTemplate) tpl.TemplateParseFinder {
+	return struct {
+		tpl.TemplateParser
+		tpl.TemplateLookup
+		tpl.TemplateLookupVariant
+	}{
+		tt,
+		tt,
+		new(nopLookupVariant),
 	}
-	return nil
-}
 
-// AddTemplate parses and adds a template to the collection.
-// Templates with name prefixed with "_text" will be handled as plain
-// text templates.
-// TODO(bep) clean up these addTemplate variants
-func (t *templateHandler) AddTemplate(name, tpl string) error {
-	h := t.getTemplateHandler(name)
-	_, err := h.addTemplate(name, tpl)
-	if err != nil {
-		return err
-	}
-	return nil
 }
 
-// MarkReady marks the templates as "ready for execution". No changes allowed
-// after this is set.
-// TODO(bep) if this proves to be resource heavy, we could detect
-// earlier if we really need this, or make it lazy.
-func (t *templateHandler) MarkReady() error {
-	if err := t.postTransform(); err != nil {
-		return err
-	}
+type templateHandlerCommon struct {
+	// shortcodes maps shortcode name to template variants
+	// (language, output format etc.) of that shortcode.
+	shortcodes map[string]*shortcodeTemplates
 
-	if t.html.clone == nil {
-		t.html.clone = template.Must(t.html.t.Clone())
-		t.html.cloneClone = template.Must(t.html.clone.Clone())
-	}
-	if t.text.clone == nil {
-		t.text.clone = texttemplate.Must(t.text.t.Clone())
-		t.text.cloneClone = texttemplate.Must(t.text.clone.Clone())
-	}
+	// templateInfo maps template name to some additional information about that template.
+	// Note that for shortcodes that same information is embedded in the
+	// shortcodeTemplates type.
+	templateInfo map[string]tpl.Info
 
-	return nil
+	// text holds all the pure text templates.
+	text *textTemplates
+	html *htmlTemplates
 }
 
-// RebuildClone rebuilds the cloned templates. Used for live-reloads.
-func (t *templateHandler) RebuildClone() {
-	if t.html != nil && t.html.cloneClone != nil {
-		t.html.clone = template.Must(t.html.cloneClone.Clone())
-	}
-	if t.text != nil && t.text.cloneClone != nil {
-		t.text.clone = texttemplate.Must(t.text.cloneClone.Clone())
-	}
+func (t templateHandlerCommon) withNewHandler(h *templateHandler) *templateHandlerCommon {
+	t.text = t.text.withNewHandler(h)
+	t.html = t.html.withNewHandler(h)
+	return &t
 }
 
-func (t *templateHandler) loadTemplates(prefix string) error {
+type templateLoader interface {
+	addLateTemplate(name, tpl string) error
+	addTemplate(name, tpl string) (*templateContext, error)
+	handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error
+}
 
-	walker := func(path string, fi hugofs.FileMetaInfo, err error) error {
-		if err != nil || fi.IsDir() {
-			return err
-		}
+// Shared by both HTML and text templates.
+type templatesCommon struct {
+	handler *templateHandler
 
-		if isDotFile(path) || isBackupFile(path) || isBaseTemplate(path) {
-			return nil
-		}
+	// Used to get proper filenames in errors
+	nameBaseTemplateName map[string]string
 
-		workingDir := t.PathSpec.WorkingDir
+	// Holds names of the templates not found during the first AST transformation
+	// pass.
+	transformNotFound map[string]bool
+}
 
-		descriptor := output.TemplateLookupDescriptor{
-			WorkingDir:    workingDir,
-			RelPath:       path,
-			Prefix:        prefix,
-			OutputFormats: t.OutputFormatsConfig,
-			FileExists: func(filename string) (bool, error) {
-				return helpers.Exists(filename, t.Layouts.Fs)
-			},
-			ContainsAny: func(filename string, subslices [][]byte) (bool, error) {
-				return helpers.FileContainsAny(filename, subslices, t.Layouts.Fs)
-			},
-		}
+func (t templatesCommon) withNewHandler(h *templateHandler) *templatesCommon {
+	t.handler = h
+	return &t
+}
 
-		tplID, err := output.CreateTemplateNames(descriptor)
-		if err != nil {
-			t.Log.ERROR.Printf("Failed to resolve template in path %q: %s", path, err)
-			return nil
-		}
+type textTemplate struct {
+	mu sync.RWMutex
+	t  *texttemplate.Template
+}
 
-		if err := t.addTemplateFile(tplID.Name, tplID.MasterFilename, tplID.OverlayFilename); err != nil {
-			return err
-		}
+func (t *textTemplate) Lookup(name string) (tpl.Template, bool) {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
 
-		return nil
-	}
+	tpl := t.t.Lookup(name)
+	return tpl, tpl != nil
+}
 
-	if err := helpers.SymbolicWalk(t.Layouts.Fs, "", walker); err != nil {
-		if !os.IsNotExist(err) {
-			return err
-		}
-		return nil
-	}
-
-	return nil
-
+func (t *textTemplate) Parse(name, tpl string) (tpl.Template, error) {
+	return t.parseIn(t.t, name, tpl)
 }
 
-func (t *templateHandler) initFuncs() {
+func (t *textTemplate) parseIn(tt *texttemplate.Template, name, tpl string) (*texttemplate.Template, error) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
 
-	// Both template types will get their own funcster instance, which
-	// in the current case contains the same set of funcs.
-	funcMap := createFuncMap(t.Deps)
-	for _, funcsterHolder := range []templateFuncsterSetter{t.html, t.text} {
-		funcster := newTemplateFuncster(t.Deps)
-
-		// The URL funcs in the funcMap is somewhat language dependent,
-		// so we need to wait until the language and site config is loaded.
-		funcster.initFuncMap(funcMap)
-
-		funcsterHolder.setTemplateFuncster(funcster)
-
+	templ, err := tt.New(name).Parse(tpl)
+	if err != nil {
+		return nil, err
 	}
 
-	for _, v := range t.shortcodes {
-		for _, variant := range v.variants {
-			t.setFuncMapInTemplate(variant.templ, funcMap)
-		}
+	if _, err := applyTemplateTransformersToTextTemplate(templateUndefined, templ); err != nil {
+		return nil, err
 	}
+	return templ, nil
+}
 
+type textTemplates struct {
+	*templatesCommon
+	*textTemplate
+	standalone *textTemplate
+	clone      *texttemplate.Template
+	cloneClone *texttemplate.Template
+
+	overlays map[string]*texttemplate.Template
 }
 
-func (t *templateHandler) getTemplateHandler(name string) templateLoader {
-	if strings.HasPrefix(name, textTmplNamePrefix) {
-		return t.text
+func (t *textTemplates) Lookup(name string) (tpl.Template, bool) {
+	templ := t.lookup(name)
+	if templ == nil {
+		return nil, false
 	}
-	return t.html
+	return templ, true
 }
 
-func (t *templateHandler) handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error {
-	h := t.getTemplateHandler(name)
-	return h.handleMaster(name, overlayFilename, masterFilename, onMissing)
+func (t *textTemplates) LookupVariant(name string, variants tpl.TemplateVariants) (tpl.Template, bool, bool) {
+	return t.handler.LookupVariant(name, variants)
 }
 
-func (t *htmlTemplates) handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error {
+func (t *textTemplates) addLateTemplate(name, tpl string) error {
+	_, err := t.addTemplateIn(t.clone, name, tpl)
+	return err
+}
 
-	masterTpl := t.lookup(masterFilename)
+func (t *textTemplates) addTemplate(name, tpl string) (*templateContext, error) {
+	return t.addTemplateIn(t.t, name, tpl)
+}
 
-	if masterTpl == nil {
-		templ, err := onMissing(masterFilename)
-		if err != nil {
-			return err
-		}
-
-		masterTpl, err = t.t.New(overlayFilename).Parse(templ.template)
-		if err != nil {
-			return templ.errWithFileContext("parse master failed", err)
-		}
+func (t *textTemplates) addTemplateIn(tt *texttemplate.Template, name, tpl string) (*templateContext, error) {
+	name = strings.TrimPrefix(name, textTmplNamePrefix)
+	templ, err := t.parseIn(tt, name, tpl)
+	if err != nil {
+		return nil, err
 	}
 
-	templ, err := onMissing(overlayFilename)
+	typ := resolveTemplateType(name)
+
+	c, err := applyTemplateTransformersToTextTemplate(typ, templ)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	overlayTpl, err := template.Must(masterTpl.Clone()).Parse(templ.template)
-	if err != nil {
-		return templ.errWithFileContext("parse failed", err)
+	for k := range c.notFound {
+		t.transformNotFound[k] = true
 	}
 
-	// The extra lookup is a workaround, see
-	// * https://github.com/golang/go/issues/16101
-	// * https://github.com/gohugoio/hugo/issues/2549
-	overlayTpl = overlayTpl.Lookup(overlayTpl.Name())
-	if _, err := applyTemplateTransformersToHMLTTemplate(templateUndefined, overlayTpl); err != nil {
-		return err
+	if typ == templateShortcode {
+		t.handler.addShortcodeVariant(name, c.Info, templ)
+	} else {
+		t.handler.templateInfo[name] = c.Info
 	}
 
-	t.overlays[name] = overlayTpl
-	t.nameBaseTemplateName[name] = masterFilename
-
-	return err
-
+	return c, nil
 }
 
 func (t *textTemplates) handleMaster(name, overlayFilename, masterFilename string, onMissing func(filename string) (templateInfo, error)) error {
@@ -868,119 +934,67 @@
 
 }
 
-func removeLeadingBOM(s string) string {
-	const bom = '\ufeff'
+func (t *textTemplates) lookup(name string) *texttemplate.Template {
 
-	for i, r := range s {
-		if i == 0 && r != bom {
-			return s
+	// Need to check in the overlay registry first as it will also be found below.
+	if t.overlays != nil {
+		if templ, ok := t.overlays[name]; ok {
+			return templ
 		}
-		if i > 0 {
-			return s[i:]
-		}
 	}
 
-	return s
+	if templ := t.t.Lookup(name); templ != nil {
+		return templ
+	}
 
-}
-
-func (t *templateHandler) addTemplateFile(name, baseTemplatePath, path string) error {
-	t.checkState()
-
-	t.Log.DEBUG.Printf("Add template file: name %q, baseTemplatePath %q, path %q", name, baseTemplatePath, path)
-
-	getTemplate := func(filename string) (templateInfo, error) {
-		fs := t.Layouts.Fs
-		b, err := afero.ReadFile(fs, filename)
-		if err != nil {
-			return templateInfo{filename: filename, fs: fs}, err
-		}
-
-		s := removeLeadingBOM(string(b))
-
-		realFilename := filename
-		if fi, err := fs.Stat(filename); err == nil {
-			if fim, ok := fi.(hugofs.FileMetaInfo); ok {
-				realFilename = fim.Meta().Filename()
-			}
-		}
-
-		return templateInfo{template: s, filename: filename, realFilename: realFilename, fs: fs}, nil
+	if t.clone != nil {
+		return t.clone.Lookup(name)
 	}
 
-	// get the suffix and switch on that
-	ext := filepath.Ext(path)
-	switch ext {
-	case ".amber":
-		helpers.Deprecated("Amber templates are no longer supported.", "Use Go templates or a Hugo version <= 0.60.", true)
-		return nil
-	case ".ace":
-		helpers.Deprecated("ACE templates are no longer supported.", "Use Go templates or a Hugo version <= 0.60.", true)
-		return nil
-	default:
+	return nil
+}
 
-		if baseTemplatePath != "" {
-			return t.handleMaster(name, path, baseTemplatePath, getTemplate)
-		}
+func (t textTemplates) withNewHandler(h *templateHandler) *textTemplates {
+	t.templatesCommon = t.templatesCommon.withNewHandler(h)
+	return &t
+}
 
-		templ, err := getTemplate(path)
+func isBackupFile(path string) bool {
+	return path[len(path)-1] == '~'
+}
 
-		if err != nil {
-			return err
-		}
-
-		err = t.AddTemplate(name, templ.template)
-		if err != nil {
-			return templ.errWithFileContext("parse failed", err)
-		}
-		return nil
-	}
+func isBaseTemplate(path string) bool {
+	return strings.Contains(filepath.Base(path), baseFileBase)
 }
 
-var embeddedTemplatesAliases = map[string][]string{
-	"shortcodes/twitter.html": {"shortcodes/tweet.html"},
+func isDotFile(path string) bool {
+	return filepath.Base(path)[0] == '.'
 }
 
-func (t *templateHandler) loadEmbedded() error {
-	for _, kv := range embedded.EmbeddedTemplates {
-		name, templ := kv[0], kv[1]
-		if err := t.addInternalTemplate(name, templ); err != nil {
-			return err
-		}
-		if aliases, found := embeddedTemplatesAliases[name]; found {
-			for _, alias := range aliases {
-				if err := t.addInternalTemplate(alias, templ); err != nil {
-					return err
-				}
-			}
+func removeLeadingBOM(s string) string {
+	const bom = '\ufeff'
 
+	for i, r := range s {
+		if i == 0 && r != bom {
+			return s
 		}
+		if i > 0 {
+			return s[i:]
+		}
 	}
 
-	return nil
+	return s
 
 }
 
-func (t *templateHandler) addInternalTemplate(name, tpl string) error {
-	return t.AddTemplate("_internal/"+name, tpl)
-}
-
-func (t *templateHandler) checkState() {
-	if t.html.clone != nil || t.text.clone != nil {
-		panic("template is cloned and cannot be modfified")
+// resolves _internal/shortcodes/param.html => param.html etc.
+func templateBaseName(typ templateType, name string) string {
+	name = strings.TrimPrefix(name, internalPathPrefix)
+	switch typ {
+	case templateShortcode:
+		return strings.TrimPrefix(name, shortcodesPathPrefix)
+	default:
+		panic("not implemented")
 	}
-}
 
-func isDotFile(path string) bool {
-	return filepath.Base(path)[0] == '.'
-}
-
-func isBackupFile(path string) bool {
-	return path[len(path)-1] == '~'
-}
-
-const baseFileBase = "baseof"
-
-func isBaseTemplate(path string) bool {
-	return strings.Contains(filepath.Base(path), baseFileBase)
 }
--- a/tpl/tplimpl/templateFuncster.go
+++ b/tpl/tplimpl/templateFuncster.go
@@ -12,22 +12,3 @@
 // limitations under the License.
 
 package tplimpl
-
-import (
-	"html/template"
-
-	"github.com/gohugoio/hugo/deps"
-)
-
-// Some of the template funcs are'nt entirely stateless.
-type templateFuncster struct {
-	funcMap template.FuncMap
-
-	*deps.Deps
-}
-
-func newTemplateFuncster(deps *deps.Deps) *templateFuncster {
-	return &templateFuncster{
-		Deps: deps,
-	}
-}
--- a/tpl/tplimpl/templateProvider.go
+++ b/tpl/tplimpl/templateProvider.go
@@ -29,8 +29,8 @@
 	newTmpl := newTemplateAdapter(deps)
 	deps.Tmpl = newTmpl
 	deps.TextTmpl = newTmpl.wrapTextTemplate(newTmpl.text.standalone)
-
-	newTmpl.initFuncs()
+	// These needs to be there at parse time.
+	newTmpl.initTemplateExecuter()
 
 	if err := newTmpl.loadEmbedded(); err != nil {
 		return err
--- a/tpl/tplimpl/template_ast_transformers.go
+++ b/tpl/tplimpl/template_ast_transformers.go
@@ -14,10 +14,8 @@
 package tplimpl
 
 import (
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
+	template "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
 
-	"strings"
-
 	texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
 	"github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate/parse"
 
@@ -27,19 +25,6 @@
 	"github.com/pkg/errors"
 )
 
-// decl keeps track of the variable mappings, i.e. $mysite => .Site etc.
-type decl map[string]string
-
-const (
-	paramsIdentifier = "Params"
-)
-
-// Containers that may contain Params that we will not touch.
-var reservedContainers = map[string]bool{
-	// Aka .Site.Data.Params which must stay case sensitive.
-	"Data": true,
-}
-
 type templateType int
 
 const (
@@ -49,7 +34,6 @@
 )
 
 type templateContext struct {
-	decl     decl
 	visited  map[string]bool
 	notFound map[string]bool
 	lookupFn func(name string) *parse.Tree
@@ -89,7 +73,6 @@
 	return &templateContext{
 		Info:     tpl.Info{Config: tpl.DefaultConfig},
 		lookupFn: lookupFn,
-		decl:     make(map[string]string),
 		visited:  make(map[string]bool),
 		notFound: make(map[string]bool)}
 }
@@ -219,11 +202,6 @@
 		}
 	case *parse.PipeNode:
 		c.collectConfig(x)
-		if len(x.Decl) == 1 && len(x.Cmds) == 1 {
-			// maps $site => .Site etc.
-			c.decl[x.Decl[0].Ident[0]] = x.Cmds[0].String()
-		}
-
 		for i, cmd := range x.Cmds {
 			keep, _ := c.applyTransformations(cmd)
 			if !keep {
@@ -237,17 +215,8 @@
 
 		for _, elem := range x.Args {
 			switch an := elem.(type) {
-			case *parse.FieldNode:
-				c.updateIdentsIfNeeded(an.Ident)
-			case *parse.VariableNode:
-				c.updateIdentsIfNeeded(an.Ident)
 			case *parse.PipeNode:
 				c.applyTransformations(an)
-			case *parse.ChainNode:
-				// site.Params...
-				if len(an.Field) > 1 && an.Field[0] == paramsIdentifier {
-					c.updateIdentsIfNeeded(an.Field)
-				}
 			}
 		}
 		return keep, c.err
@@ -262,19 +231,6 @@
 	}
 }
 
-func (c *templateContext) updateIdentsIfNeeded(idents []string) {
-	index := c.decl.indexOfReplacementStart(idents)
-
-	if index == -1 {
-		return
-	}
-
-	for i := index; i < len(idents); i++ {
-		idents[i] = strings.ToLower(idents[i])
-	}
-
-}
-
 func (c *templateContext) hasIdent(idents []string, ident string) bool {
 	for _, id := range idents {
 		if id == ident {
@@ -375,161 +331,4 @@
 
 	return false
 
-}
-
-// indexOfReplacementStart will return the index of where to start doing replacement,
-// -1 if none needed.
-func (d decl) indexOfReplacementStart(idents []string) int {
-
-	l := len(idents)
-
-	if l == 0 {
-		return -1
-	}
-
-	if l == 1 {
-		first := idents[0]
-		if first == "" || first == paramsIdentifier || first[0] == '$' {
-			// This can not be a Params.x
-			return -1
-		}
-	}
-
-	var lookFurther bool
-	var needsVarExpansion bool
-	for _, ident := range idents {
-		if ident[0] == '$' {
-			lookFurther = true
-			needsVarExpansion = true
-			break
-		} else if ident == paramsIdentifier {
-			lookFurther = true
-			break
-		}
-	}
-
-	if !lookFurther {
-		return -1
-	}
-
-	var resolvedIdents []string
-
-	if !needsVarExpansion {
-		resolvedIdents = idents
-	} else {
-		var ok bool
-		resolvedIdents, ok = d.resolveVariables(idents)
-		if !ok {
-			return -1
-		}
-	}
-
-	var paramFound bool
-	for i, ident := range resolvedIdents {
-		if ident == paramsIdentifier {
-			if i > 0 {
-				container := resolvedIdents[i-1]
-				if reservedContainers[container] {
-					// .Data.Params.someKey
-					return -1
-				}
-			}
-
-			paramFound = true
-			break
-		}
-	}
-
-	if !paramFound {
-		return -1
-	}
-
-	var paramSeen bool
-	idx := -1
-	for i, ident := range idents {
-		if ident == "" || ident[0] == '$' {
-			continue
-		}
-
-		if ident == paramsIdentifier {
-			paramSeen = true
-			idx = -1
-
-		} else {
-			if paramSeen {
-				return i
-			}
-			if idx == -1 {
-				idx = i
-			}
-		}
-	}
-	return idx
-
-}
-
-func (d decl) resolveVariables(idents []string) ([]string, bool) {
-	var (
-		replacements []string
-		replaced     []string
-	)
-
-	// An Ident can start out as one of
-	// [Params] [$blue] [$colors.Blue]
-	// We need to resolve the variables, so
-	// $blue => [Params Colors Blue]
-	// etc.
-	replacements = []string{idents[0]}
-
-	// Loop until there are no more $vars to resolve.
-	for i := 0; i < len(replacements); i++ {
-
-		if i > 20 {
-			// bail out
-			return nil, false
-		}
-
-		potentialVar := replacements[i]
-
-		if potentialVar == "$" {
-			continue
-		}
-
-		if potentialVar == "" || potentialVar[0] != '$' {
-			// leave it as is
-			replaced = append(replaced, strings.Split(potentialVar, ".")...)
-			continue
-		}
-
-		replacement, ok := d[potentialVar]
-
-		if !ok {
-			// Temporary range vars. We do not care about those.
-			return nil, false
-		}
-
-		if !d.isKeyword(replacement) {
-			continue
-		}
-
-		replacement = strings.TrimPrefix(replacement, ".")
-
-		if replacement == "" {
-			continue
-		}
-
-		if replacement[0] == '$' {
-			// Needs further expansion
-			replacements = append(replacements, strings.Split(replacement, ".")...)
-		} else {
-			replaced = append(replaced, strings.Split(replacement, ".")...)
-		}
-	}
-
-	return append(replaced, idents[1:]...), true
-
-}
-
-func (d decl) isKeyword(s string) bool {
-	return !strings.ContainsAny(s, " -\"")
 }
--- a/tpl/tplimpl/template_ast_transformers_test.go
+++ b/tpl/tplimpl/template_ast_transformers_test.go
@@ -13,400 +13,18 @@
 package tplimpl
 
 import (
-	"bytes"
-	"fmt"
-	"github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
+	"strings"
 
+	template "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
+
 	"testing"
 	"time"
 
 	"github.com/gohugoio/hugo/tpl"
 
-	"github.com/spf13/cast"
-
 	qt "github.com/frankban/quicktest"
 )
 
-type paramsHolder struct {
-	params map[string]interface{}
-	page   *paramsHolder
-}
-
-func (p paramsHolder) Params() map[string]interface{} {
-	return p.params
-}
-
-func (p paramsHolder) GetPage(arg string) *paramsHolder {
-	return p.page
-}
-
-var (
-	testFuncs = map[string]interface{}{
-		"getif":  func(v interface{}) interface{} { return v },
-		"ToTime": func(v interface{}) interface{} { return cast.ToTime(v) },
-		"First":  func(v ...interface{}) interface{} { return v[0] },
-		"Echo":   func(v interface{}) interface{} { return v },
-		"where": func(seq, key interface{}, args ...interface{}) (interface{}, error) {
-			return map[string]interface{}{
-				"ByWeight": fmt.Sprintf("%v:%v:%v", seq, key, args),
-			}, nil
-		},
-		"site": func() paramsHolder {
-			return paramsHolder{
-				params: map[string]interface{}{
-					"lower": "global-site",
-				},
-				page: &paramsHolder{
-					params: map[string]interface{}{
-						"lower": "page",
-					},
-				},
-			}
-		},
-	}
-
-	paramsData = map[string]interface{}{
-
-		"NotParam": "Hi There",
-		"Slice":    []int{1, 3},
-		"Params": map[string]interface{}{
-			"lower":  "P1L",
-			"slice":  []int{1, 3},
-			"mydate": "1972-01-28",
-		},
-		"Pages": map[string]interface{}{
-			"ByWeight": []int{1, 3},
-		},
-		"CurrentSection": map[string]interface{}{
-			"Params": map[string]interface{}{
-				"lower": "pcurrentsection",
-			},
-		},
-		"Site": map[string]interface{}{
-			"Params": map[string]interface{}{
-				"lower": "P2L",
-				"slice": []int{1, 3},
-			},
-			"Language": map[string]interface{}{
-				"Params": map[string]interface{}{
-					"lower": "P22L",
-					"nested": map[string]interface{}{
-						"lower": "P22L_nested",
-					},
-				},
-			},
-			"Data": map[string]interface{}{
-				"Params": map[string]interface{}{
-					"NOLOW": "P3H",
-				},
-			},
-		},
-		"Site2": paramsHolder{
-			params: map[string]interface{}{
-				"lower": "global-site",
-			},
-			page: &paramsHolder{
-				params: map[string]interface{}{
-					"lower": "page",
-				},
-			},
-		},
-	}
-
-	paramsTempl = `
-{{ $page := . }}
-{{ $pages := .Pages }}
-{{ $pageParams := .Params }}
-{{ $site := .Site }}
-{{ $siteParams := .Site.Params }}
-{{ $data := .Site.Data }}
-{{ $notparam := .NotParam }}
-
-PCurrentSection: {{ .CurrentSection.Params.LOWER }}
-P1: {{ .Params.LOWER }}
-P1_2: {{ $.Params.LOWER }}
-P1_3: {{ $page.Params.LOWER }}
-P1_4: {{ $pageParams.LOWER }}
-P2: {{ .Site.Params.LOWER }}
-P2_2: {{ $.Site.Params.LOWER }}
-P2_3: {{ $site.Params.LOWER }}
-P2_4: {{ $siteParams.LOWER }}
-P22: {{ .Site.Language.Params.LOWER }}
-P22_nested: {{ .Site.Language.Params.NESTED.LOWER }}
-P3: {{ .Site.Data.Params.NOLOW }}
-P3_2: {{ $.Site.Data.Params.NOLOW }}
-P3_3: {{ $site.Data.Params.NOLOW }}
-P3_4: {{ $data.Params.NOLOW }}
-P4: {{ range $i, $e := .Site.Params.SLICE }}{{ $e }}{{ end }}
-P5: {{ Echo .Params.LOWER }}
-P5_2: {{ Echo $site.Params.LOWER }}
-{{ if .Params.LOWER }}
-IF: {{ .Params.LOWER }}
-{{ end }}
-{{ if .Params.NOT_EXIST }}
-{{ else }}
-ELSE: {{ .Params.LOWER }}
-{{ end }}
-
-
-{{ with .Params.LOWER }}
-WITH: {{ . }}
-{{ end }}
-
-
-{{ range .Slice }}
-RANGE: {{ . }}: {{ $.Params.LOWER }}
-{{ end }}
-{{ index .Slice 1 }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ .NotParam }}
-{{ $notparam }}
-
-
-{{ $lower := .Site.Params.LOWER }}
-F1: {{ printf "themes/%s-theme" .Site.Params.LOWER }}
-F2: {{ Echo (printf "themes/%s-theme" $lower) }}
-F3: {{ Echo (printf "themes/%s-theme" .Site.Params.LOWER) }}
-
-PSLICE: {{ range .Params.SLICE }}PSLICE{{.}}|{{ end }}
-
-{{ $pages := "foo" }}
-{{ $pages := where $pages ".Params.toc_hide" "!=" true }}
-PARAMS STRING: {{ $pages.ByWeight }}
-PARAMS STRING2: {{ with $pages }}{{ .ByWeight }}{{ end }}
-{{ $pages3 := where ".Params.TOC_HIDE" "!=" .Params.LOWER }}
-PARAMS STRING3: {{ $pages3.ByWeight }}
-{{ $first := First .Pages .Site.Params.LOWER }}
-PARAMS COMPOSITE: {{ $first.ByWeight }}
-
-
-{{ $time := $.Params.MyDate | ToTime }}
-{{ $time = $time.AddDate 0 1 0 }}
-PARAMS TIME: {{ $time.Format "2006-01-02" }}
-
-{{ $_x :=  $.Params.MyDate | ToTime }}
-PARAMS TIME2: {{ $_x.AddDate 0 1 0 }}
-
-PARAMS SITE GLOBAL1: {{ site.Params.LOwER }}
-{{ $lower := site.Params.LOwER }}
-{{ $site := site }}
-PARAMS SITE GLOBAL2: {{ $lower }}
-PARAMS SITE GLOBAL3: {{ $site.Params.LOWER }}
-
-{{ $p := $site.GetPage "foo" }}
-PARAMS GETPAGE: {{ $p.Params.LOWER }}
-{{ $p := .Site2.GetPage "foo" }}
-PARAMS GETPAGE2: {{ $p.Params.LOWER }}
-`
-)
-
-func TestParamsKeysToLower(t *testing.T) {
-	t.Parallel()
-	c := qt.New(t)
-
-	_, err := applyTemplateTransformers(templateUndefined, nil, nil)
-	c.Assert(err, qt.Not(qt.IsNil))
-
-	templ, err := template.New("foo").Funcs(testFuncs).Parse(paramsTempl)
-
-	c.Assert(err, qt.IsNil)
-
-	ctx := newTemplateContext(createParseTreeLookup(templ))
-
-	c.Assert(ctx.decl.indexOfReplacementStart([]string{}), qt.Equals, -1)
-
-	ctx.applyTransformations(templ.Tree.Root)
-
-	var b bytes.Buffer
-
-	c.Assert(templ.Execute(&b, paramsData), qt.IsNil)
-
-	result := b.String()
-
-	c.Assert(result, qt.Contains, "P1: P1L")
-	c.Assert(result, qt.Contains, "P1_2: P1L")
-	c.Assert(result, qt.Contains, "P1_3: P1L")
-	c.Assert(result, qt.Contains, "P1_4: P1L")
-	c.Assert(result, qt.Contains, "P2: P2L")
-	c.Assert(result, qt.Contains, "P2_2: P2L")
-	c.Assert(result, qt.Contains, "P2_3: P2L")
-	c.Assert(result, qt.Contains, "P2_4: P2L")
-	c.Assert(result, qt.Contains, "P22: P22L")
-	c.Assert(result, qt.Contains, "P22_nested: P22L_nested")
-	c.Assert(result, qt.Contains, "P3: P3H")
-	c.Assert(result, qt.Contains, "P3_2: P3H")
-	c.Assert(result, qt.Contains, "P3_3: P3H")
-	c.Assert(result, qt.Contains, "P3_4: P3H")
-	c.Assert(result, qt.Contains, "P4: 13")
-	c.Assert(result, qt.Contains, "P5: P1L")
-	c.Assert(result, qt.Contains, "P5_2: P2L")
-
-	c.Assert(result, qt.Contains, "IF: P1L")
-	c.Assert(result, qt.Contains, "ELSE: P1L")
-
-	c.Assert(result, qt.Contains, "WITH: P1L")
-
-	c.Assert(result, qt.Contains, "RANGE: 3: P1L")
-
-	c.Assert(result, qt.Contains, "Hi There")
-
-	// Issue #2740
-	c.Assert(result, qt.Contains, "F1: themes/P2L-theme")
-	c.Assert(result, qt.Contains, "F2: themes/P2L-theme")
-	c.Assert(result, qt.Contains, "F3: themes/P2L-theme")
-
-	c.Assert(result, qt.Contains, "PSLICE: PSLICE1|PSLICE3|")
-	c.Assert(result, qt.Contains, "PARAMS STRING: foo:.Params.toc_hide:[!= true]")
-	c.Assert(result, qt.Contains, "PARAMS STRING2: foo:.Params.toc_hide:[!= true]")
-	c.Assert(result, qt.Contains, "PARAMS STRING3: .Params.TOC_HIDE:!=:[P1L]")
-
-	// Issue #5094
-	c.Assert(result, qt.Contains, "PARAMS COMPOSITE: [1 3]")
-
-	// Issue #5068
-	c.Assert(result, qt.Contains, "PCurrentSection: pcurrentsection")
-
-	// Issue #5541
-	c.Assert(result, qt.Contains, "PARAMS TIME: 1972-02-28")
-	c.Assert(result, qt.Contains, "PARAMS TIME2: 1972-02-28")
-
-	// Issue ##5615
-	c.Assert(result, qt.Contains, "PARAMS SITE GLOBAL1: global-site")
-	c.Assert(result, qt.Contains, "PARAMS SITE GLOBAL2: global-site")
-	c.Assert(result, qt.Contains, "PARAMS SITE GLOBAL3: global-site")
-
-	//
-	c.Assert(result, qt.Contains, "PARAMS GETPAGE: page")
-	c.Assert(result, qt.Contains, "PARAMS GETPAGE2: page")
-
-}
-
-func BenchmarkTemplateParamsKeysToLower(b *testing.B) {
-	templ, err := template.New("foo").Funcs(testFuncs).Parse(paramsTempl)
-
-	if err != nil {
-		b.Fatal(err)
-	}
-
-	templates := make([]*template.Template, b.N)
-
-	for i := 0; i < b.N; i++ {
-		templates[i], err = templ.Clone()
-		if err != nil {
-			b.Fatal(err)
-		}
-	}
-
-	b.ResetTimer()
-
-	for i := 0; i < b.N; i++ {
-		c := newTemplateContext(createParseTreeLookup(templates[i]))
-		c.applyTransformations(templ.Tree.Root)
-	}
-}
-
-func TestParamsKeysToLowerVars(t *testing.T) {
-	t.Parallel()
-	c := qt.New(t)
-
-	var (
-		data = map[string]interface{}{
-			"Params": map[string]interface{}{
-				"colors": map[string]interface{}{
-					"blue": "Amber",
-					"pretty": map[string]interface{}{
-						"first": "Indigo",
-					},
-				},
-			},
-		}
-
-		// This is how Amber behaves:
-		paramsTempl = `
-{{$__amber_1 := .Params.Colors}}
-{{$__amber_2 := $__amber_1.Blue}}
-{{$__amber_3 := $__amber_1.Pretty}}
-{{$__amber_4 := .Params}}
-
-Color: {{$__amber_2}}
-Blue: {{ $__amber_1.Blue}}
-Pretty First1: {{ $__amber_3.First}}
-Pretty First2: {{ $__amber_1.Pretty.First}}
-Pretty First3: {{ $__amber_4.COLORS.PRETTY.FIRST}}
-`
-	)
-
-	templ, err := template.New("foo").Parse(paramsTempl)
-
-	c.Assert(err, qt.IsNil)
-
-	ctx := newTemplateContext(createParseTreeLookup(templ))
-
-	ctx.applyTransformations(templ.Tree.Root)
-
-	var b bytes.Buffer
-
-	c.Assert(templ.Execute(&b, data), qt.IsNil)
-
-	result := b.String()
-
-	c.Assert(result, qt.Contains, "Color: Amber")
-	c.Assert(result, qt.Contains, "Blue: Amber")
-	c.Assert(result, qt.Contains, "Pretty First1: Indigo")
-	c.Assert(result, qt.Contains, "Pretty First2: Indigo")
-	c.Assert(result, qt.Contains, "Pretty First3: Indigo")
-
-}
-
-func TestParamsKeysToLowerInBlockTemplate(t *testing.T) {
-	t.Parallel()
-	c := qt.New(t)
-
-	var (
-		data = map[string]interface{}{
-			"Params": map[string]interface{}{
-				"lower": "P1L",
-			},
-		}
-
-		master = `
-P1: {{ .Params.LOWER }}
-{{ block "main" . }}DEFAULT{{ end }}`
-		overlay = `
-{{ define "main" }}
-P2: {{ .Params.LOWER }}
-{{ end }}`
-	)
-
-	masterTpl, err := template.New("foo").Parse(master)
-	c.Assert(err, qt.IsNil)
-
-	overlayTpl, err := template.Must(masterTpl.Clone()).Parse(overlay)
-	c.Assert(err, qt.IsNil)
-	overlayTpl = overlayTpl.Lookup(overlayTpl.Name())
-
-	ctx := newTemplateContext(createParseTreeLookup(overlayTpl))
-
-	ctx.applyTransformations(overlayTpl.Tree.Root)
-
-	var b bytes.Buffer
-
-	c.Assert(overlayTpl.Execute(&b, data), qt.IsNil)
-
-	result := b.String()
-
-	c.Assert(result, qt.Contains, "P1: P1L")
-	c.Assert(result, qt.Contains, "P2: P1L")
-}
-
 // Issue #2927
 func TestTransformRecursiveTemplate(t *testing.T) {
 	c := qt.New(t)
@@ -479,7 +97,7 @@
 	)
 
 	d := newD(c)
-	h := d.Tmpl.(tpl.TemplateHandler)
+	h := d.Tmpl.(tpl.TemplateManager)
 
 	// HTML templates
 	c.Assert(h.AddTemplate("mytemplate.html", templ1), qt.IsNil)
@@ -493,8 +111,12 @@
 
 	for _, name := range []string{"mytemplate.html", "mytexttemplate.txt"} {
 		tt, _ := d.Tmpl.Lookup(name)
-		result, err := tt.(tpl.TemplateExecutor).ExecuteToString(ctx)
+		sb := &strings.Builder{}
+
+		err := d.Tmpl.Execute(tt, sb, ctx)
 		c.Assert(err, qt.IsNil)
+
+		result := sb.String()
 
 		c.Assert(result, qt.Contains, ".True: TRUE")
 		c.Assert(result, qt.Contains, ".TimeZero1: FALSE")
--- a/tpl/tplimpl/template_funcs.go
+++ b/tpl/tplimpl/template_funcs.go
@@ -16,8 +16,14 @@
 package tplimpl
 
 import (
-	"html/template"
+	"reflect"
+	"strings"
 
+	"github.com/gohugoio/hugo/common/maps"
+
+	template "github.com/gohugoio/hugo/tpl/internal/go_templates/htmltemplate"
+	texttemplate "github.com/gohugoio/hugo/tpl/internal/go_templates/texttemplate"
+
 	"github.com/gohugoio/hugo/deps"
 
 	"github.com/gohugoio/hugo/tpl/internal"
@@ -49,7 +55,55 @@
 	_ "github.com/gohugoio/hugo/tpl/urls"
 )
 
+var _ texttemplate.ExecHelper = (*templateExecHelper)(nil)
+var zero reflect.Value
+
+type templateExecHelper struct {
+	funcs map[string]reflect.Value
+}
+
+func (t *templateExecHelper) GetFunc(name string) (reflect.Value, bool) {
+	if fn, found := t.funcs[name]; found {
+		return fn, true
+	}
+	return zero, false
+}
+
+func (t *templateExecHelper) GetMapValue(receiver, key reflect.Value) (reflect.Value, bool) {
+	if params, ok := receiver.Interface().(maps.Params); ok {
+		// Case insensitive.
+		keystr := strings.ToLower(key.String())
+		v, found := params[keystr]
+		if !found {
+			return zero, false
+		}
+		return reflect.ValueOf(v), true
+	}
+
+	v := receiver.MapIndex(key)
+
+	return v, v.IsValid()
+}
+
+func newTemplateExecuter(d *deps.Deps) (texttemplate.Executer, map[string]reflect.Value) {
+	funcs := createFuncMap(d)
+	funcsv := make(map[string]reflect.Value)
+
+	for k, v := range funcs {
+		funcsv[k] = reflect.ValueOf(v)
+	}
+
+	exeHelper := &templateExecHelper{
+		funcs: funcsv,
+	}
+
+	return texttemplate.NewExecuter(
+		exeHelper,
+	), funcsv
+}
+
 func createFuncMap(d *deps.Deps) map[string]interface{} {
+
 	funcMap := template.FuncMap{}
 
 	// Merge the namespace funcs
@@ -71,10 +125,12 @@
 
 	}
 
+	if d.OverloadedTemplateFuncs != nil {
+		for k, v := range d.OverloadedTemplateFuncs {
+			funcMap[k] = v
+		}
+	}
+
 	return funcMap
 
-}
-func (t *templateFuncster) initFuncMap(funcMap template.FuncMap) {
-	t.funcMap = funcMap
-	t.Tmpl.(*templateHandler).setFuncs(funcMap)
 }
--- a/tpl/tplimpl/template_funcs_test.go
+++ b/tpl/tplimpl/template_funcs_test.go
@@ -119,7 +119,7 @@
 		for _, mm := range ns.MethodMappings {
 			for i, example := range mm.Examples {
 				in, expected := example[0], example[1]
-				d.WithTemplate = func(templ tpl.TemplateHandler) error {
+				d.WithTemplate = func(templ tpl.TemplateManager) error {
 					c.Assert(templ.AddTemplate("test", in), qt.IsNil)
 					c.Assert(templ.AddTemplate("partials/header.html", "<title>Hugo Rocks!</title>"), qt.IsNil)
 					return nil
@@ -128,7 +128,7 @@
 
 				var b bytes.Buffer
 				templ, _ := d.Tmpl.Lookup("test")
-				c.Assert(templ.Execute(&b, &data), qt.IsNil)
+				c.Assert(d.Tmpl.Execute(templ, &b, &data), qt.IsNil)
 				if b.String() != expected {
 					t.Fatalf("%s[%d]: got %q expected %q", ns.Name, i, b.String(), expected)
 				}
@@ -154,7 +154,7 @@
 
 	config := newDepsConfig(v)
 
-	config.WithTemplate = func(templ tpl.TemplateHandler) error {
+	config.WithTemplate = func(templ tpl.TemplateManager) error {
 		err := templ.AddTemplate("partials/"+name, partial)
 		if err != nil {
 			return err
@@ -208,7 +208,7 @@
 func doBenchmarkPartial(b *testing.B, f func(ns *partials.Namespace) error) {
 	c := qt.New(b)
 	config := newDepsConfig(viper.New())
-	config.WithTemplate = func(templ tpl.TemplateHandler) error {
+	config.WithTemplate = func(templ tpl.TemplateManager) error {
 		err := templ.AddTemplate("partials/bench1", `{{ shuffle (seq 1 10) }}`)
 		if err != nil {
 			return err
--- a/tpl/tplimpl/template_info_test.go
+++ b/tpl/tplimpl/template_info_test.go
@@ -24,7 +24,7 @@
 func TestTemplateInfoShortcode(t *testing.T) {
 	c := qt.New(t)
 	d := newD(c)
-	h := d.Tmpl.(tpl.TemplateHandler)
+	h := d.Tmpl.(tpl.TemplateManager)
 
 	c.Assert(h.AddTemplate("shortcodes/mytemplate.html", `
 {{ .Inner }}