Replace all usage of CopyOnWriteFs with OverlayFs

Fixes #9761

hugofs/language_composite_fs.go

@@ -1,81 +0,0 @@
-// Copyright 2018 The Hugo Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package hugofs
-
-import (
-	"os"
-
-	"github.com/spf13/afero"
-)
-
-var (
-	_ afero.Fs             = (*languageCompositeFs)(nil)
-	_ afero.Lstater        = (*languageCompositeFs)(nil)
-	_ FilesystemsUnwrapper = (*languageCompositeFs)(nil)
-)
-
-type languageCompositeFs struct {
-	base    afero.Fs
-	overlay afero.Fs
-	*afero.CopyOnWriteFs
-}
-
-// NewLanguageCompositeFs creates a composite and language aware filesystem.
-// This is a hybrid filesystem. To get a specific file in Open, Stat etc., use the full filename
-// to the target filesystem. This information is available in Readdir, Stat etc. via the
-// special LanguageFileInfo FileInfo implementation.
-func NewLanguageCompositeFs(base, overlay afero.Fs) afero.Fs {
-	return &languageCompositeFs{base, overlay, afero.NewCopyOnWriteFs(base, overlay).(*afero.CopyOnWriteFs)}
-}
-
-func (fs *languageCompositeFs) UnwrapFilesystems() []afero.Fs {
-	return []afero.Fs{fs.base, fs.overlay}
-}
-
-// Open takes the full path to the file in the target filesystem. If it is a directory, it gets merged
-// using the language as a weight.
-func (fs *languageCompositeFs) Open(name string) (afero.File, error) {
-	f, err := fs.CopyOnWriteFs.Open(name)
-	if err != nil {
-		return nil, err
-	}
-
-	fu, ok := f.(*afero.UnionFile)
-	if ok {
-		// This is a directory: Merge it.
-		fu.Merger = LanguageDirsMerger
-	}
-	return f, nil
-}
-
-// LanguageDirsMerger implements the afero.DirsMerger interface, which is used
-// to merge two directories.
-var LanguageDirsMerger = func(lofi, bofi []os.FileInfo) ([]os.FileInfo, error) {
-	for _, fi1 := range bofi {
-		fim1 := fi1.(FileMetaInfo)
-		var found bool
-		for _, fi2 := range lofi {
-			fim2 := fi2.(FileMetaInfo)
-			if fi1.Name() == fi2.Name() && fim1.Meta().Lang == fim2.Meta().Lang {
-				found = true
-				break
-			}
-		}
-		if !found {
-			lofi = append(lofi, fi1)
-		}
-	}
-
-	return lofi, nil
-}

hugofs/language_merge.go

@@ -0,0 +1,39 @@
+// Copyright 2022 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugofs
+
+import (
+	"os"
+)
+
+// LanguageDirsMerger implements the overlayfs.DirsMerger func, which is used
+// to merge two directories.
+var LanguageDirsMerger = func(lofi, bofi []os.FileInfo) []os.FileInfo {
+	for _, fi1 := range bofi {
+		fim1 := fi1.(FileMetaInfo)
+		var found bool
+		for _, fi2 := range lofi {
+			fim2 := fi2.(FileMetaInfo)
+			if fi1.Name() == fi2.Name() && fim1.Meta().Lang == fim2.Meta().Lang {
+				found = true
+				break
+			}
+		}
+		if !found {
+			lofi = append(lofi, fi1)
+		}
+	}
+
+	return lofi
+}

hugofs/noop_fs.go

@@ -38,11 +38,11 @@ func (fs noOpFs) Create(name string) (afero.File, error) {
 }
 
 func (fs noOpFs) Mkdir(name string, perm os.FileMode) error {
-	return errNoOp
+	return nil
 }
 
 func (fs noOpFs) MkdirAll(path string, perm os.FileMode) error {
-	return errNoOp
+	return nil
 }
 
 func (fs noOpFs) Open(name string) (afero.File, error) {
@@ -54,11 +54,11 @@ func (fs noOpFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File,
 }
 
 func (fs noOpFs) Remove(name string) error {
-	return errNoOp
+	return nil
 }
 
 func (fs noOpFs) RemoveAll(path string) error {
-	return errNoOp
+	return nil
 }
 
 func (fs noOpFs) Rename(oldname string, newname string) error {