tocss: Fix the import resolving from absolute to relative assets paths

Fixes #12137

hugofs/rootmapping_fs.go

@@ -338,12 +338,17 @@ func (c ComponentPath) ComponentPathJoined() string {
 
 type ReverseLookupProvder interface {
 	ReverseLookup(filename string, checkExists bool) ([]ComponentPath, error)
+	ReverseLookupComponent(component, filename string, checkExists bool) ([]ComponentPath, error)
 }
 
 // func (fs *RootMappingFs) ReverseStat(filename string) ([]FileMetaInfo, error)
-func (fs *RootMappingFs) ReverseLookup(in string, checkExists bool) ([]ComponentPath, error) {
-	in = fs.cleanName(in)
-	key := filepathSeparator + in
+func (fs *RootMappingFs) ReverseLookup(filename string, checkExists bool) ([]ComponentPath, error) {
+	return fs.ReverseLookupComponent("", filename, checkExists)
+}
+
+func (fs *RootMappingFs) ReverseLookupComponent(component, filename string, checkExists bool) ([]ComponentPath, error) {
+	filename = fs.cleanName(filename)
+	key := filepathSeparator + filename
 
 	s, roots := fs.getRootsReverse(key)
 
@@ -357,6 +362,9 @@ func (fs *RootMappingFs) ReverseLookup(in string, checkExists bool) ([]Component
 	dir, name := filepath.Split(base)
 
 	for _, first := range roots {
+		if component != "" && first.FromBase != component {
+			continue
+		}
 		if first.Meta.Rename != nil {
 			name = first.Meta.Rename(name, true)
 		}

hugolib/filesystems/basefs.go

@@ -362,7 +362,7 @@ func (d *SourceFilesystem) ReverseLookup(filename string, checkExists bool) ([]h
 	var cps []hugofs.ComponentPath
 	hugofs.WalkFilesystems(d.Fs, func(fs afero.Fs) bool {
 		if rfs, ok := fs.(hugofs.ReverseLookupProvder); ok {
-			if c, err := rfs.ReverseLookup(filename, checkExists); err == nil {
+			if c, err := rfs.ReverseLookupComponent(d.Name, filename, checkExists); err == nil {
 				cps = append(cps, c...)
 			}
 		}

hugolib/filesystems/basefs_test.go

@@ -478,6 +478,36 @@ Home.
 	_ = stat("blog/b1.md")
 }
 
+func TestReverseLookupShouldOnlyConsiderFilesInCurrentComponent(t *testing.T) {
+	files := `
+-- hugo.toml --
+baseURL = "https://example.com/"
+[module]
+[[module.mounts]]
+source = "files/layouts"
+target = "layouts"
+[[module.mounts]]
+source = "files/layouts/assets"
+target = "assets"
+-- files/layouts/l1.txt --
+l1
+-- files/layouts/assets/l2.txt --
+l2
+`
+	b := hugolib.Test(t, files)
+
+	assetsFs := b.H.Assets
+
+	for _, checkExists := range []bool{false, true} {
+		cps, err := assetsFs.ReverseLookup(filepath.FromSlash("files/layouts/assets/l2.txt"), checkExists)
+		b.Assert(err, qt.IsNil)
+		b.Assert(cps, qt.HasLen, 1)
+		cps, err = assetsFs.ReverseLookup(filepath.FromSlash("files/layouts/l2.txt"), checkExists)
+		b.Assert(err, qt.IsNil)
+		b.Assert(cps, qt.HasLen, 0)
+	}
+}
+
 func TestStaticComposite(t *testing.T) {
 	files := `
 -- hugo.toml --

resources/resource_transformers/tocss/dartsass/transform.go

@@ -144,7 +144,7 @@ func (t importResolver) CanonicalizeURL(url string) (string, error) {
 	var pathDir string
 	if isURL {
 		var found bool
-		prevDir, found = t.c.sfs.MakePathRelative(filepath.Dir(filePath), false)
+		prevDir, found = t.c.sfs.MakePathRelative(filepath.Dir(filePath), true)
 
 		if !found {
 			// Not a member of this filesystem, let Dart Sass handle it.

resources/resource_transformers/tocss/scss/tocss.go

@@ -86,7 +86,7 @@ func (t *toCSSTransformation) Transform(ctx *resources.ResourceTransformationCtx
 		if prev == "stdin" {
 			prevDir = baseDir
 		} else {
-			prevDir, _ = t.c.sfs.MakePathRelative(filepath.Dir(prev), false)
+			prevDir, _ = t.c.sfs.MakePathRelative(filepath.Dir(prev), true)
 
 			if prevDir == "" {
 				// Not a member of this filesystem. Let LibSASS handle it.