output: Support templates per site/language

This applies to both regular templates and shortcodes. So, if the site language is French and the output format is AMP, this is the (start) of the lookup order for the home page:

1. index.fr.amp.html
2. index.amp.html
3. index.fr.html
4. index.html
5. ...

Fixes #3360

4 files changed, 50 insertions, 12 deletions

diff --git a/hugolib/hugo_sites_build_test.go b/hugolib/hugo_sites_build_test.go
index c343f6087..96e2c66b2 100644
--- a/hugolib/hugo_sites_build_test.go
+++ b/hugolib/hugo_sites_build_test.go
@@ -305,12 +305,12 @@ func doTestMultiSitesBuild(t *testing.T, configTemplate, configSuffix string) {
 	require.True(t, strings.Contains(languageRedirect, "0; url=http://example.com/blog/fr"), languageRedirect)
 
 	// check home page content (including data files rendering)
-	th.assertFileContent("public/en/index.html", "Home Page 1", "Hello", "Hugo Rocks!")
-	th.assertFileContent("public/fr/index.html", "Home Page 1", "Bonjour", "Hugo Rocks!")
+	th.assertFileContent("public/en/index.html", "Default Home Page 1", "Hello", "Hugo Rocks!")
+	th.assertFileContent("public/fr/index.html", "French Home Page 1", "Bonjour", "Hugo Rocks!")
 
 	// check single page content
-	th.assertFileContent("public/fr/sect/doc1/index.html", "Single", "Shortcode: Bonjour")
-	th.assertFileContent("public/en/sect/doc1-slug/index.html", "Single", "Shortcode: Hello")
+	th.assertFileContent("public/fr/sect/doc1/index.html", "Single", "Shortcode: Bonjour", "LingoFrench")
+	th.assertFileContent("public/en/sect/doc1-slug/index.html", "Single", "Shortcode: Hello", "LingoDefault")
 
 	// Check node translations
 	homeEn := enSite.getPage(KindHome)
@@ -1042,7 +1042,14 @@ func createMultiTestSitesForConfig(t *testing.T, siteConfig testSiteConfig, conf
 
 	if err := afero.WriteFile(mf,
 		filepath.Join("layouts", "index.html"),
-		[]byte("{{ $p := .Paginator }}Home Page {{ $p.PageNumber }}: {{ .Title }}|{{ .IsHome }}|{{ i18n \"hello\" }}|{{ .Permalink }}|{{  .Site.Data.hugo.slogan }}"),
+		[]byte("{{ $p := .Paginator }}Default Home Page {{ $p.PageNumber }}: {{ .Title }}|{{ .IsHome }}|{{ i18n \"hello\" }}|{{ .Permalink }}|{{  .Site.Data.hugo.slogan }}"),
+		0755); err != nil {
+		t.Fatalf("Failed to write layout file: %s", err)
+	}
+
+	if err := afero.WriteFile(mf,
+		filepath.Join("layouts", "index.fr.html"),
+		[]byte("{{ $p := .Paginator }}French Home Page {{ $p.PageNumber }}: {{ .Title }}|{{ .IsHome }}|{{ i18n \"hello\" }}|{{ .Permalink }}|{{  .Site.Data.hugo.slogan }}"),
 		0755); err != nil {
 		t.Fatalf("Failed to write layout file: %s", err)
 	}
@@ -1055,6 +1062,21 @@ func createMultiTestSitesForConfig(t *testing.T, siteConfig testSiteConfig, conf
 		t.Fatalf("Failed to write layout file: %s", err)
 	}
 
+	// A shortcode in multiple languages
+	if err := afero.WriteFile(mf,
+		filepath.Join("layouts", "shortcodes", "lingo.html"),
+		[]byte("LingoDefault"),
+		0755); err != nil {
+		t.Fatalf("Failed to write layout file: %s", err)
+	}
+
+	if err := afero.WriteFile(mf,
+		filepath.Join("layouts", "shortcodes", "lingo.fr.html"),
+		[]byte("LingoFrench"),
+		0755); err != nil {
+		t.Fatalf("Failed to write layout file: %s", err)
+	}
+
 	// Add some language files
 	if err := afero.WriteFile(mf,
 		filepath.Join("i18n", "en.yaml"),
@@ -1098,6 +1120,8 @@ publishdate: "2000-01-01"
 
 {{< shortcode >}}
 
+{{< lingo >}}
+
 NOTE: slug should be used as URL
 `)},
 		{Name: filepath.FromSlash("sect/doc1.fr.md"), Content: []byte(`---
@@ -1113,6 +1137,8 @@ publishdate: "2000-01-04"
 
 {{< shortcode >}}
 
+{{< lingo >}}
+
 NOTE: should be in the 'en' Page's 'Translations' field.
 NOTE: date is after "doc3"
 `)},
diff --git a/hugolib/page.go b/hugolib/page.go
index cf0a2144c..0f44b8b99 100644
--- a/hugolib/page.go
+++ b/hugolib/page.go
@@ -250,6 +250,7 @@ func (p *Page) createLayoutDescriptor() output.LayoutDescriptor {
 	return output.LayoutDescriptor{
 		Kind:    p.Kind,
 		Type:    p.Type(),
+		Lang:    p.Lang(),
 		Layout:  p.Layout,
 		Section: section,
 	}
diff --git a/hugolib/shortcode.go b/hugolib/shortcode.go
index 150d82c44..3cf472f82 100644
--- a/hugolib/shortcode.go
+++ b/hugolib/shortcode.go
@@ -157,6 +157,7 @@ func (sc shortcode) String() string {
 // Note that in the below, OutputFormat may be empty.
 // We will try to look for the most specific shortcode template available.
 type scKey struct {
+	Lang                 string
 	OutputFormat         string
 	Suffix               string
 	ShortcodePlaceholder string
@@ -166,8 +167,8 @@ func newScKey(m media.Type, shortcodeplaceholder string) scKey {
 	return scKey{Suffix: m.Suffix, ShortcodePlaceholder: shortcodeplaceholder}
 }
 
-func newScKeyFromOutputFormat(o output.Format, shortcodeplaceholder string) scKey {
-	return scKey{Suffix: o.MediaType.Suffix, OutputFormat: o.Name, ShortcodePlaceholder: shortcodeplaceholder}
+func newScKeyFromLangAndOutputFormat(lang string, o output.Format, shortcodeplaceholder string) scKey {
+	return scKey{Lang: lang, Suffix: o.MediaType.Suffix, OutputFormat: o.Name, ShortcodePlaceholder: shortcodeplaceholder}
 }
 
 func newDefaultScKey(shortcodeplaceholder string) scKey {
@@ -251,10 +252,11 @@ const innerCleanupExpand = "$1"
 func prepareShortcodeForPage(placeholder string, sc shortcode, parent *ShortcodeWithPage, p *Page) map[scKey]func() (string, error) {
 
 	m := make(map[scKey]func() (string, error))
+	lang := p.Lang()
 
 	for _, f := range p.outputFormats {
 		// The most specific template will win.
-		key := newScKeyFromOutputFormat(f, placeholder)
+		key := newScKeyFromLangAndOutputFormat(lang, f, placeholder)
 		m[key] = func() (string, error) {
 			return renderShortcode(key, sc, nil, p), nil
 		}
@@ -371,9 +373,11 @@ func (s *shortcodeHandler) updateDelta() bool {
 
 func (s *shortcodeHandler) contentShortcodesForOutputFormat(f output.Format) map[scKey]func() (string, error) {
 	contentShortcodesForOuputFormat := make(map[scKey]func() (string, error))
+	lang := s.p.Lang()
+
 	for shortcodePlaceholder := range s.shortcodes {
 
-		key := newScKeyFromOutputFormat(f, shortcodePlaceholder)
+		key := newScKeyFromLangAndOutputFormat(lang, f, shortcodePlaceholder)
 		renderFn, found := s.contentShortcodes[key]
 
 		if !found {
@@ -390,7 +394,7 @@ func (s *shortcodeHandler) contentShortcodesForOutputFormat(f output.Format) map
 		if !found {
 			panic(fmt.Sprintf("Shortcode %q could not be found", shortcodePlaceholder))
 		}
-		contentShortcodesForOuputFormat[newScKeyFromOutputFormat(f, shortcodePlaceholder)] = renderFn
+		contentShortcodesForOuputFormat[newScKeyFromLangAndOutputFormat(lang, f, shortcodePlaceholder)] = renderFn
 	}
 
 	return contentShortcodesForOuputFormat
@@ -676,12 +680,19 @@ func getShortcodeTemplateForTemplateKey(key scKey, shortcodeName string, t tpl.T
 
 	suffix := strings.ToLower(key.Suffix)
 	outFormat := strings.ToLower(key.OutputFormat)
+	lang := strings.ToLower(key.Lang)
 
 	if outFormat != "" && suffix != "" {
+		if lang != "" {
+			names = append(names, fmt.Sprintf("%s.%s.%s.%s", shortcodeName, lang, outFormat, suffix))
+		}
 		names = append(names, fmt.Sprintf("%s.%s.%s", shortcodeName, outFormat, suffix))
 	}
 
 	if suffix != "" {
+		if lang != "" {
+			names = append(names, fmt.Sprintf("%s.%s.%s", shortcodeName, lang, suffix))
+		}
 		names = append(names, fmt.Sprintf("%s.%s", shortcodeName, suffix))
 	}
 
diff --git a/hugolib/shortcode_test.go b/hugolib/shortcode_test.go
index 42da9e465..3d355f947 100644
--- a/hugolib/shortcode_test.go
+++ b/hugolib/shortcode_test.go
@@ -837,8 +837,8 @@ func TestReplaceShortcodeTokens(t *testing.T) {
 func TestScKey(t *testing.T) {
 	require.Equal(t, scKey{Suffix: "xml", ShortcodePlaceholder: "ABCD"},
 		newScKey(media.XMLType, "ABCD"))
-	require.Equal(t, scKey{Suffix: "html", OutputFormat: "AMP", ShortcodePlaceholder: "EFGH"},
-		newScKeyFromOutputFormat(output.AMPFormat, "EFGH"))
+	require.Equal(t, scKey{Lang: "en", Suffix: "html", OutputFormat: "AMP", ShortcodePlaceholder: "EFGH"},
+		newScKeyFromLangAndOutputFormat("en", output.AMPFormat, "EFGH"))
 	require.Equal(t, scKey{Suffix: "html", ShortcodePlaceholder: "IJKL"},
 		newDefaultScKey("IJKL"))