Reimplement and simplify Hugo's template system

See #13541 for details.

Fixes #13545
Fixes #13515
Closes #7964
Closes #13365
Closes #12988
Closes #4891

resources/kinds/kinds.go

@@ -34,6 +34,7 @@ const (
 
 	// The following are (currently) temporary nodes,
 	// i.e. nodes we create just to render in isolation.
+	KindTemporary    = "temporary"
 	KindRSS          = "rss"
 	KindSitemap      = "sitemap"
 	KindSitemapIndex = "sitemapindex"

resources/page/page.go

@@ -150,8 +150,8 @@ type InSectionPositioner interface {
 
 // InternalDependencies is considered an internal interface.
 type InternalDependencies interface {
-	// GetRelatedDocsHandler is for internal use only.
-	GetRelatedDocsHandler() *RelatedDocsHandler
+	// GetInternalRelatedDocsHandler is for internal use only.
+	GetInternalRelatedDocsHandler() *RelatedDocsHandler
 }
 
 // OutputFormatsProvider provides the OutputFormats of a Page.

resources/page/page_paths.go

@@ -145,7 +145,7 @@ func CreateTargetPaths(d TargetPathDescriptor) (tp TargetPaths) {
 		pb.isUgly = true
 	}
 
-	if d.Type == output.HTTPStatusHTMLFormat || d.Type == output.SitemapFormat || d.Type == output.RobotsTxtFormat {
+	if d.Type == output.HTTPStatus404HTMLFormat || d.Type == output.SitemapFormat || d.Type == output.RobotsTxtFormat {
 		pb.noSubResources = true
 	} else if d.Kind != kinds.KindPage && d.URL == "" && d.Section.Base() != "/" {
 		if d.ExpandedPermalink != "" {

resources/page/pages_related.go

@@ -129,7 +129,7 @@ func (p Pages) withInvertedIndex(ctx context.Context, search func(idx *related.I
 		return nil, fmt.Errorf("invalid type %T in related search", p[0])
 	}
 
-	cache := d.GetRelatedDocsHandler()
+	cache := d.GetInternalRelatedDocsHandler()
 
 	searchIndex, err := cache.getOrCreateIndex(ctx, p)
 	if err != nil {

resources/page/testhelpers_test.go

@@ -221,7 +221,7 @@ func (p *testPage) GetTerms(taxonomy string) Pages {
 	panic("testpage: not implemented")
 }
 
-func (p *testPage) GetRelatedDocsHandler() *RelatedDocsHandler {
+func (p *testPage) GetInternalRelatedDocsHandler() *RelatedDocsHandler {
 	return relatedDocsHandler
 }
 

resources/resource_spec.go

@@ -42,7 +42,6 @@ import (
 	"github.com/gohugoio/hugo/resources/images"
 	"github.com/gohugoio/hugo/resources/page"
 	"github.com/gohugoio/hugo/resources/resource"
-	"github.com/gohugoio/hugo/tpl"
 )
 
 func NewSpec(
@@ -123,8 +122,6 @@ type Spec struct {
 	BuildClosers types.CloseAdder
 	Rebuilder    identity.SignalRebuilder
 
-	TextTemplates tpl.TemplateParseFinder
-
 	Permalinks page.PermalinkExpander
 
 	ImageCache *ImageCache

resources/resource_transformers/templates/execute_as_template.go

@@ -23,17 +23,17 @@ import (
 	"github.com/gohugoio/hugo/resources"
 	"github.com/gohugoio/hugo/resources/internal"
 	"github.com/gohugoio/hugo/resources/resource"
-	"github.com/gohugoio/hugo/tpl"
+	"github.com/gohugoio/hugo/tpl/tplimpl"
 )
 
 // Client contains methods to perform template processing of Resource objects.
 type Client struct {
 	rs *resources.Spec
-	t  tpl.TemplatesProvider
+	t  tplimpl.TemplateStoreProvider
 }
 
 // New creates a new Client with the given specification.
-func New(rs *resources.Spec, t tpl.TemplatesProvider) *Client {
+func New(rs *resources.Spec, t tplimpl.TemplateStoreProvider) *Client {
 	if rs == nil {
 		panic("must provide a resource Spec")
 	}
@@ -45,7 +45,7 @@ func New(rs *resources.Spec, t tpl.TemplatesProvider) *Client {
 
 type executeAsTemplateTransform struct {
 	rs         *resources.Spec
-	t          tpl.TemplatesProvider
+	t          tplimpl.TemplateStoreProvider
 	targetPath string
 	data       any
 }
@@ -56,14 +56,13 @@ func (t *executeAsTemplateTransform) Key() internal.ResourceTransformationKey {
 
 func (t *executeAsTemplateTransform) Transform(ctx *resources.ResourceTransformationCtx) error {
 	tplStr := helpers.ReaderToString(ctx.From)
-	templ, err := t.t.TextTmpl().Parse(ctx.InPath, tplStr)
+	th := t.t.GetTemplateStore()
+	ti, err := th.TextParse(ctx.InPath, tplStr)
 	if err != nil {
 		return fmt.Errorf("failed to parse Resource %q as Template:: %w", ctx.InPath, err)
 	}
-
 	ctx.OutPath = t.targetPath
-
-	return t.t.Tmpl().ExecuteWithContext(ctx.Ctx, templ, ctx.To, t.data)
+	return th.ExecuteWithContext(ctx.Ctx, ti, ctx.To, t.data)
 }
 
 func (c *Client) ExecuteAsTemplate(ctx context.Context, res resources.ResourceTransformer, targetPath string, data any) (resource.Resource, error) {