Fix filename dimension identifiers (_role_X_, _version_X_) to replace mount config

Filename identifiers for roles and versions were parsed but never applied
to the SitesMatrix. Now they replace the mount's configuration for that
dimension, matching how language identifiers already worked.

Fixes #14756

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hugolib/sitesmatrix/dimensions.go

@@ -214,7 +214,9 @@ type VectorProvider interface {
 type VectorStore interface {
 	VectorProvider
 	Complement(...VectorProvider) VectorStore
-	WithLanguageIndices(i int) VectorStore
+	WithLanguageIndices(i ...int) VectorStore
+	WithVersionIndices(i ...int) VectorStore
+	WithRoleIndices(i ...int) VectorStore
 	HasLanguage(lang int) bool
 	HasVersion(version int) bool
 	HasRole(role int) bool

hugolib/sitesmatrix/sitematrix_integration_test.go

@@ -1901,3 +1901,55 @@ title: p1 de
 </ul>
 	`)
 }
+
+// Issue 14756.
+func TestFilenameIdentifierShouldReplaceMountDimension(t *testing.T) {
+	t.Parallel()
+	files := `
+-- hugo.toml --
+baseURL = "https://example.org/"
+disableKinds = ["taxonomy", "term", "rss", "sitemap"]
+defaultContentLanguage = "en"
+defaultContentRole = "guest"
+defaultContentRoleInSubdir = true
+[roles]
+[roles.guest]
+weight = 100
+[roles.member]
+weight = 200
+[module]
+[[module.mounts]]
+source = 'content/member'
+target = 'content'
+[module.mounts.sites.matrix]
+roles = "member"
+[[module.mounts]]
+source = 'content/guest'
+target = 'content'
+[module.mounts.sites.matrix]
+roles = "*"
+-- content/member/bundle/index.md --
+---
+title: "Bundle"
+---
+-- content/guest/bundle/index.md --
+---
+title: "Bundle"
+---
+-- content/guest/bundle/img._role_member_.txt --
+memberimg
+-- content/guest/bundle/guestimg.txt --
+guestimg
+-- layouts/page.html --
+Role: {{ .Site.Role.Name }}|{{ range .Resources }}{{ .Name }}|{{ end }}$
+-- layouts/list.html --
+List.
+`
+
+	b := hugolib.Test(t, files)
+
+	// The guest role should only see guestimg.txt (not img._role_member_.txt).
+	b.AssertFileContent("public/guest/bundle/index.html", "Role: guest|guestimg.txt|$")
+	// The member role should see both.
+	b.AssertFileContent("public/member/bundle/index.html", "Role: member|guestimg.txt|img._role_member_.txt|$")
+}

hugolib/sitesmatrix/vectorstores.go

@@ -209,17 +209,46 @@ func (s *vectorStoreMap) Vectors() []Vector {
 	return vectors
 }
 
-func (s *vectorStoreMap) WithLanguageIndices(i int) VectorStore {
+func (s *vectorStoreMap) WithLanguageIndices(i ...int) VectorStore {
 	c := s.clone()
 
 	for v := range c.sets {
-		v[Language] = i
-		c.sets[v] = struct{}{}
+		for _, i := range i {
+			nv := v
+			nv[Language] = i
+			c.sets[nv] = struct{}{}
+		}
 	}
 
 	return c
 }
 
+func (s *vectorStoreMap) WithVersionIndices(indices ...int) VectorStore {
+	old := s.clone()
+	c := newVectorStoreMap(len(old.sets) * len(indices))
+	for v := range old.sets {
+		for _, i := range indices {
+			nv := v
+			nv[Version] = i
+			c.sets[nv] = struct{}{}
+		}
+	}
+	return c
+}
+
+func (s *vectorStoreMap) WithRoleIndices(indices ...int) VectorStore {
+	old := s.clone()
+	c := newVectorStoreMap(len(old.sets) * len(indices))
+	for v := range old.sets {
+		for _, i := range indices {
+			nv := v
+			nv[Role] = i
+			c.sets[nv] = struct{}{}
+		}
+	}
+	return c
+}
+
 func (s *vectorStoreMap) HasLanguage(i int) bool {
 	for v := range s.sets {
 		if v.Language() == i {
@@ -589,10 +618,24 @@ func (s IntSets) shallowClone() *IntSets {
 	return &s
 }
 
-// WithLanguageIndices replaces the current language set with a single language index.
-func (s *IntSets) WithLanguageIndices(i int) VectorStore {
+// WithLanguageIndices replaces the current language set with the given language indices.
+func (s *IntSets) WithLanguageIndices(indices ...int) VectorStore {
 	c := s.shallowClone()
-	c.languages = hmaps.NewOrderedIntSet(i)
+	c.languages = hmaps.NewOrderedIntSet(indices...)
+	return c.init()
+}
+
+// WithVersionIndices replaces the current version set with the given version indices.
+func (s *IntSets) WithVersionIndices(indices ...int) VectorStore {
+	c := s.shallowClone()
+	c.versions = hmaps.NewOrderedIntSet(indices...)
+	return c.init()
+}
+
+// WithRoleIndices replaces the current role set with the given role indices.
+func (s *IntSets) WithRoleIndices(indices ...int) VectorStore {
+	c := s.shallowClone()
+	c.roles = hmaps.NewOrderedIntSet(indices...)
 	return c.init()
 }