hugolib: Fix bundle header clone logic

Fixes #6136

2 files changed, 98 insertions, 12 deletions

diff --git a/hugolib/pagebundler_test.go b/hugolib/pagebundler_test.go
index f5a6d9a84..5c21dc472 100644
--- a/hugolib/pagebundler_test.go
+++ b/hugolib/pagebundler_test.go
@@ -1075,3 +1075,84 @@ slug: leaf
 		filepath.FromSlash("section|sect1/sect2/_index.md|CurrentSection: sect1/sect2/_index.md"))
 
 }
+
+// Issue 6136
+func TestPageBundlerPartialTranslations(t *testing.T) {
+	config := `
+baseURL = "https://example.org"
+defaultContentLanguage = "en"
+defaultContentLanguageInSubDir = true
+disableKinds = ["taxonomyTerm", "taxonomy"]
+
+[languages]
+[languages.nn]
+languageName = "Nynorsk"
+weight = 2
+title = "Tittel på Nynorsk"
+
+[languages.en]
+title = "Title in English"
+languageName = "English"
+weight = 1
+
+`
+
+	pageContent := func(id string) string {
+		return fmt.Sprintf(`
+---
+title: %q
+---
+`, id)
+	}
+
+	dataContent := func(id string) string {
+		return id
+	}
+
+	b := newTestSitesBuilder(t).WithConfigFile("toml", config)
+
+	b.WithContent("blog/sect1/_index.nn.md", pageContent("s1.nn"))
+	b.WithContent("blog/sect1/data.json", dataContent("s1.data"))
+
+	b.WithContent("blog/sect1/b1/index.nn.md", pageContent("s1.b1.nn"))
+	b.WithContent("blog/sect1/b1/data.json", dataContent("s1.b1.data"))
+
+	b.WithContent("blog/sect2/_index.md", pageContent("s2"))
+	b.WithContent("blog/sect2/data.json", dataContent("s2.data"))
+
+	b.WithContent("blog/sect2/b1/index.md", pageContent("s2.b1"))
+	b.WithContent("blog/sect2/b1/data.json", dataContent("s2.b1.data"))
+
+	b.WithContent("blog/sect2/b2/index.md", pageContent("s2.b2"))
+	b.WithContent("blog/sect2/b2/bp.md", pageContent("s2.b2.bundlecontent"))
+
+	b.WithContent("blog/sect2/b3/index.md", pageContent("s2.b3"))
+	b.WithContent("blog/sect2/b3/bp.nn.md", pageContent("s2.b3.bundlecontent.nn"))
+
+	b.WithContent("blog/sect2/b4/index.nn.md", pageContent("s2.b4"))
+	b.WithContent("blog/sect2/b4/bp.nn.md", pageContent("s2.b4.bundlecontent.nn"))
+
+	b.WithTemplates("index.html", `
+Num Pages: {{ len .Site.Pages }}
+{{ range .Site.Pages }}
+{{ .Kind }}|{{ .RelPermalink }}|Content: {{ .Title }}|Resources: {{ range .Resources }}R: {{ .Title }}|{{ .Content }}|{{ end -}}
+{{ end }}
+`)
+
+	b.Build(BuildCfg{})
+
+	b.AssertFileContent("public/nn/index.html",
+		"Num Pages: 6",
+		"page|/nn/blog/sect1/b1/|Content: s1.b1.nn|Resources: R: data.json|s1.b1.data|",
+		"page|/nn/blog/sect2/b3/|Content: s2.b3|Resources: R: s2.b3.bundlecontent.nn|",
+		"page|/nn/blog/sect2/b4/|Content: s2.b4|Resources: R: s2.b4.bundlecontent.nn",
+	)
+
+	b.AssertFileContent("public/en/index.html",
+		"Num Pages: 6",
+		"section|/en/blog/sect2/|Content: s2|Resources: R: data.json|s2.data|",
+		"page|/en/blog/sect2/b1/|Content: s2.b1|Resources: R: data.json|s2.b1.data|",
+		"page|/en/blog/sect2/b2/|Content: s2.b2|Resources: R: s2.b2.bundlecontent|",
+	)
+
+}
diff --git a/hugolib/pages_capture.go b/hugolib/pages_capture.go
index 094933793..361b87e84 100644
--- a/hugolib/pages_capture.go
+++ b/hugolib/pages_capture.go
@@ -344,7 +344,7 @@ func (c *pagesCollector) addToBundle(info hugofs.FileMetaInfo, btyp bundleDirTyp
 	}
 
 	cloneBundle := func(lang string) *fileinfoBundle {
-		// Every bundled file needs a content file header.
+		// Every bundled content file needs a content file header.
 		// Use the default content language if found, else just
 		// pick one.
 		var (
@@ -376,6 +376,7 @@ func (c *pagesCollector) addToBundle(info hugofs.FileMetaInfo, btyp bundleDirTyp
 	bundle := getBundle(lang)
 	isBundleHeader := c.isBundleHeader(info)
 	classifier := info.Meta().Classifier()
+	isContent := classifier == files.ContentClassContent
 	if bundle == nil {
 		if isBundleHeader {
 			bundle = &fileinfoBundle{header: info}
@@ -384,28 +385,32 @@ func (c *pagesCollector) addToBundle(info hugofs.FileMetaInfo, btyp bundleDirTyp
 			if btyp == bundleBranch {
 				// No special logic for branch bundles.
 				// Every language needs its own _index.md file.
+				// Also, we only clone bundle headers for lonsesome, bundled,
+				// content files.
 				return c.handleFiles(info)
 			}
 
-			bundle = cloneBundle(lang)
-			bundles[lang] = bundle
+			if isContent {
+				bundle = cloneBundle(lang)
+				bundles[lang] = bundle
+			}
 		}
 	}
 
-	if !isBundleHeader {
+	if !isBundleHeader && bundle != nil {
 		bundle.resources = append(bundle.resources, info)
 	}
 
 	if classifier == files.ContentClassFile {
 		translations := info.Meta().Translations()
-		if len(translations) < len(bundles) {
-			for lang, b := range bundles {
-				if !stringSliceContains(lang, translations...) && !b.containsResource(info.Name()) {
-					// Clone and add it to the bundle.
-					clone := c.cloneFileInfo(info)
-					clone.Meta()["lang"] = lang
-					b.resources = append(b.resources, clone)
-				}
+
+		for lang, b := range bundles {
+			if !stringSliceContains(lang, translations...) && !b.containsResource(info.Name()) {
+
+				// Clone and add it to the bundle.
+				clone := c.cloneFileInfo(info)
+				clone.Meta()["lang"] = lang
+				b.resources = append(b.resources, clone)
 			}
 		}
 	}