[BUG] Allow to exclude files in dump

- Move the skip path check outside the `file.IsDir()` condition, so it
can be used to skip files.
- Add unit tests.
- Resolves https://codeberg.org/forgejo/forgejo/issues/1397
- Ref: https://codeberg.org/forgejo/forgejo/pulls/1438

cmd/dump.go

@@ -454,15 +454,19 @@ func addRecursiveExclude(w archiver.Writer, insidePath, absPath string, excludeA
 	for _, file := range files {
 		currentAbsPath := filepath.Join(absPath, file.Name())
 		currentInsidePath := path.Join(insidePath, file.Name())
+
+		if util.SliceContainsString(excludeAbsPath, currentAbsPath) {
+			log.Debug("Skipping %q because matched an excluded path.", currentAbsPath)
+			continue
+		}
+
 		if file.IsDir() {
-			if !util.SliceContainsString(excludeAbsPath, currentAbsPath) {
 			if err := addFile(w, currentInsidePath, currentAbsPath, false); err != nil {
 				return err
 			}
 			if err = addRecursiveExclude(w, currentInsidePath, currentAbsPath, excludeAbsPath, verbose); err != nil {
 				return err
 			}
-			}
 		} else {
 			// only copy regular files and symlink regular files, skip non-regular files like socket/pipe/...
 			shouldAdd := file.Mode().IsRegular()

cmd/dump_test.go

@@ -0,0 +1,117 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cmd
+
+import (
+	"io"
+	"os"
+	"testing"
+
+	"github.com/mholt/archiver/v3"
+	"github.com/stretchr/testify/assert"
+)
+
+type mockArchiver struct {
+	addedFiles []string
+}
+
+func (mockArchiver) Create(out io.Writer) error {
+	return nil
+}
+
+func (m *mockArchiver) Write(f archiver.File) error {
+	m.addedFiles = append(m.addedFiles, f.Name())
+	return nil
+}
+
+func (mockArchiver) Close() error {
+	return nil
+}
+
+func TestAddRecursiveExclude(t *testing.T) {
+	t.Run("Empty", func(t *testing.T) {
+		dir := t.TempDir()
+		archiver := &mockArchiver{}
+
+		err := addRecursiveExclude(archiver, "", dir, []string{}, false)
+		assert.NoError(t, err)
+		assert.Empty(t, archiver.addedFiles)
+	})
+
+	t.Run("Single file", func(t *testing.T) {
+		dir := t.TempDir()
+		err := os.WriteFile(dir+"/example", nil, 0o666)
+		assert.NoError(t, err)
+
+		t.Run("No exclude", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, nil, false)
+			assert.NoError(t, err)
+			assert.Len(t, archiver.addedFiles, 1)
+			assert.EqualValues(t, "example", archiver.addedFiles[0])
+		})
+
+		t.Run("With exclude", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, []string{dir + "/example"}, false)
+			assert.NoError(t, err)
+			assert.Empty(t, archiver.addedFiles)
+		})
+	})
+
+	t.Run("File inside directory", func(t *testing.T) {
+		dir := t.TempDir()
+		err := os.MkdirAll(dir+"/deep/nested/folder", 0o750)
+		assert.NoError(t, err)
+		err = os.WriteFile(dir+"/deep/nested/folder/example", nil, 0o666)
+		assert.NoError(t, err)
+		err = os.WriteFile(dir+"/deep/nested/folder/another-file", nil, 0o666)
+		assert.NoError(t, err)
+
+		t.Run("No exclude", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, nil, false)
+			assert.NoError(t, err)
+			assert.Len(t, archiver.addedFiles, 5)
+			assert.EqualValues(t, "deep", archiver.addedFiles[0])
+			assert.EqualValues(t, "deep/nested", archiver.addedFiles[1])
+			assert.EqualValues(t, "deep/nested/folder", archiver.addedFiles[2])
+			assert.EqualValues(t, "deep/nested/folder/example", archiver.addedFiles[3])
+			assert.EqualValues(t, "deep/nested/folder/another-file", archiver.addedFiles[4])
+		})
+
+		t.Run("Exclude first directory", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, []string{dir + "/deep"}, false)
+			assert.NoError(t, err)
+			assert.Empty(t, archiver.addedFiles)
+		})
+
+		t.Run("Exclude nested directory", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, []string{dir + "/deep/nested/folder"}, false)
+			assert.NoError(t, err)
+			assert.Len(t, archiver.addedFiles, 2)
+			assert.EqualValues(t, "deep", archiver.addedFiles[0])
+			assert.EqualValues(t, "deep/nested", archiver.addedFiles[1])
+		})
+
+		t.Run("Exclude file", func(t *testing.T) {
+			archiver := &mockArchiver{}
+
+			err = addRecursiveExclude(archiver, "", dir, []string{dir + "/deep/nested/folder/example"}, false)
+			assert.NoError(t, err)
+			assert.Len(t, archiver.addedFiles, 4)
+			assert.EqualValues(t, "deep", archiver.addedFiles[0])
+			assert.EqualValues(t, "deep/nested", archiver.addedFiles[1])
+			assert.EqualValues(t, "deep/nested/folder", archiver.addedFiles[2])
+			assert.EqualValues(t, "deep/nested/folder/another-file", archiver.addedFiles[3])
+		})
+	})
+}