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

1 files changed, 16 insertions, 5 deletions

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))
 	}