layout: Respect Type and Layout for list template selection

This commit also has some other nice side-effects:

* The layout logic is unified for all page types, which should make it less surprising
* Page.Render now supports all types
* The legacy "indexes" type is removed from the template lookup order. This is an undocumented type from early Hugo days. This means that having a template in, say, `/layouts/indexes/list.html` will no longer work.
* The theme override logic is improved. As an example, an `index.html` in theme will now wn over a `_default/list.html` in the project, which most will expect.

Fixes #3005
Fixes #3245

Author: bep

hugolib/page_output.go

@@ -100,22 +100,19 @@ func (p *PageOutput) layouts(layouts ...string) ([]string, error) {
 		return []string{p.selfLayout}, nil
 	}
 
-	layoutOverride := ""
+	layoutDescriptor := p.layoutDescriptor
+
 	if len(layouts) > 0 {
-		layoutOverride = layouts[0]
+		layoutDescriptor.Layout = layouts[0]
+		layoutDescriptor.LayoutOverride = true
 	}
 
 	return p.s.layoutHandler.For(
-		p.layoutDescriptor,
-		layoutOverride,
+		layoutDescriptor,
 		p.outputFormat)
 }
 
 func (p *PageOutput) Render(layout ...string) template.HTML {
-	if !p.checkRender() {
-		return ""
-	}
-
 	l, err := p.layouts(layout...)
 	if err != nil {
 		helpers.DistinctErrorLog.Printf("in .Render: Failed to resolve layout %q for page %q", layout, p.pathOrTitle())
@@ -145,10 +142,6 @@ func (p *PageOutput) Render(layout ...string) template.HTML {
 }
 
 func (p *Page) Render(layout ...string) template.HTML {
-	if !p.checkRender() {
-		return ""
-	}
-
 	p.pageOutputInit.Do(func() {
 		if p.mainPageOutput != nil {
 			return
@@ -170,16 +163,6 @@ func (p *Page) Render(layout ...string) template.HTML {
 	return p.mainPageOutput.Render(layout...)
 }
 
-// We may fix this in the future, but the layout handling in Render isn't built
-// for list pages.
-func (p *Page) checkRender() bool {
-	if p.Kind != KindPage {
-		helpers.DistinctWarnLog.Printf(".Render only available for regular pages, not for of kind %q. You probably meant .Site.RegularPages and not.Site.Pages.", p.Kind)
-		return false
-	}
-	return true
-}
-
 // OutputFormats holds a list of the relevant output formats for a given resource.
 type OutputFormats []*OutputFormat
 

hugolib/site.go

@@ -1541,7 +1541,7 @@ func (s *Site) kindFromSections(sections []string) string {
 }
 
 func (s *Site) layouts(p *PageOutput) ([]string, error) {
-	return s.layoutHandler.For(p.layoutDescriptor, "", p.outputFormat)
+	return s.layoutHandler.For(p.layoutDescriptor, p.outputFormat)
 }
 
 func (s *Site) preparePages() error {

hugolib/site_render.go

@@ -242,7 +242,6 @@ func (s *Site) renderRSS(p *PageOutput) error {
 
 	layouts, err := s.layoutHandler.For(
 		p.layoutDescriptor,
-		"",
 		p.outputFormat)
 	if err != nil {
 		return err

output/docshelper.go

@@ -37,27 +37,26 @@ func createLayoutExamples() interface{} {
 	)
 
 	for _, example := range []struct {
-		name           string
-		d              LayoutDescriptor
-		hasTheme       bool
-		layoutOverride string
-		f              Format
+		name     string
+		d        LayoutDescriptor
+		hasTheme bool
+		f        Format
 	}{
-		{`AMP home, with theme "demoTheme".`, LayoutDescriptor{Kind: "home"}, true, "", AMPFormat},
-		{`AMP home, French language".`, LayoutDescriptor{Kind: "home", Lang: "fr"}, false, "", AMPFormat},
-		{"RSS home, no theme.", LayoutDescriptor{Kind: "home"}, false, "", RSSFormat},
-		{"JSON home, no theme.", LayoutDescriptor{Kind: "home"}, false, "", JSONFormat},
-		{fmt.Sprintf(`CSV regular, "layout: %s" in front matter.`, demoLayout), LayoutDescriptor{Kind: "page", Layout: demoLayout}, false, "", CSVFormat},
-		{fmt.Sprintf(`JSON regular, "type: %s" in front matter.`, demoType), LayoutDescriptor{Kind: "page", Type: demoType}, false, "", JSONFormat},
-		{"HTML regular.", LayoutDescriptor{Kind: "page"}, false, "", HTMLFormat},
-		{"AMP regular.", LayoutDescriptor{Kind: "page"}, false, "", AMPFormat},
-		{"Calendar blog section.", LayoutDescriptor{Kind: "section", Section: "blog"}, false, "", CalendarFormat},
-		{"Calendar taxonomy list.", LayoutDescriptor{Kind: "taxonomy", Section: "tag"}, false, "", CalendarFormat},
-		{"Calendar taxonomy term.", LayoutDescriptor{Kind: "taxonomyTerm", Section: "tag"}, false, "", CalendarFormat},
+		{`AMP home, with theme "demoTheme".`, LayoutDescriptor{Kind: "home"}, true, AMPFormat},
+		{`AMP home, French language".`, LayoutDescriptor{Kind: "home", Lang: "fr"}, false, AMPFormat},
+		{"RSS home, no theme.", LayoutDescriptor{Kind: "home"}, false, RSSFormat},
+		{"JSON home, no theme.", LayoutDescriptor{Kind: "home"}, false, JSONFormat},
+		{fmt.Sprintf(`CSV regular, "layout: %s" in front matter.`, demoLayout), LayoutDescriptor{Kind: "page", Layout: demoLayout}, false, CSVFormat},
+		{fmt.Sprintf(`JSON regular, "type: %s" in front matter.`, demoType), LayoutDescriptor{Kind: "page", Type: demoType}, false, JSONFormat},
+		{"HTML regular.", LayoutDescriptor{Kind: "page"}, false, HTMLFormat},
+		{"AMP regular.", LayoutDescriptor{Kind: "page"}, false, AMPFormat},
+		{"Calendar blog section.", LayoutDescriptor{Kind: "section", Section: "blog"}, false, CalendarFormat},
+		{"Calendar taxonomy list.", LayoutDescriptor{Kind: "taxonomy", Section: "tag"}, false, CalendarFormat},
+		{"Calendar taxonomy term.", LayoutDescriptor{Kind: "taxonomyTerm", Section: "tag"}, false, CalendarFormat},
 	} {
 
 		l := NewLayoutHandler(example.hasTheme)
-		layouts, _ := l.For(example.d, example.layoutOverride, example.f)
+		layouts, _ := l.For(example.d, example.f)
 
 		basicExamples = append(basicExamples, Example{
 			Example:      example.name,