Never ignore root directory when enumerating files in a repository (#683)

## Changes

The pattern `.*` in a `.gitignore` file can match `.` when walking all
files in a repository. If it does, then the walker immediately aborts
and no files are returned. The root directory (an unnamed directory)
must never be ignored.

Reported in https://github.com/databricks/databricks-vscode/issues/837.

## Tests

New tests pass.

libs/fileset/fileset.go

@@ -39,14 +39,14 @@ func (w *FileSet) Root() string {
 
 // Return all tracked files for Repo
 func (w *FileSet) All() ([]File, error) {
-	return w.RecursiveListFiles(w.root)
+	return w.recursiveListFiles()
 }
 
 // Recursively traverses dir in a depth first manner and returns a list of all files
 // that are being tracked in the FileSet (ie not being ignored for matching one of the
 // patterns in w.ignore)
-func (w *FileSet) RecursiveListFiles(dir string) (fileList []File, err error) {
-	err = filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
+func (w *FileSet) recursiveListFiles() (fileList []File, err error) {
+	err = filepath.WalkDir(w.root, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
 		}

libs/git/fileset.go

@@ -6,7 +6,7 @@ import (
 
 // FileSet is Git repository aware implementation of [fileset.FileSet].
 // It forces checking if gitignore files have been modified every
-// time a call to [FileSet.All] or [FileSet.RecursiveListFiles] is made.
+// time a call to [FileSet.All] is made.
 type FileSet struct {
 	fileset *fileset.FileSet
 	view    *View
@@ -43,11 +43,6 @@ func (f *FileSet) All() ([]fileset.File, error) {
 	return f.fileset.All()
 }
 
-func (f *FileSet) RecursiveListFiles(dir string) ([]fileset.File, error) {
-	f.view.repo.taintIgnoreRules()
-	return f.fileset.RecursiveListFiles(dir)
-}
-
 func (f *FileSet) EnsureValidGitIgnoreExists() error {
 	return f.view.EnsureValidGitIgnoreExists()
 }

libs/git/fileset_test.go

@@ -10,18 +10,23 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestFileSetRecursiveListFiles(t *testing.T) {
-	fileSet, err := NewFileSet("./testdata")
+func testFileSetAll(t *testing.T, path string) {
+	fileSet, err := NewFileSet(path)
 	require.NoError(t, err)
-	files, err := fileSet.RecursiveListFiles("./testdata")
+	files, err := fileSet.All()
 	require.NoError(t, err)
-	require.Len(t, files, 6)
-	assert.Equal(t, filepath.Join(".gitignore"), files[0].Relative)
-	assert.Equal(t, filepath.Join("a", ".gitignore"), files[1].Relative)
-	assert.Equal(t, filepath.Join("a", "b", ".gitignore"), files[2].Relative)
-	assert.Equal(t, filepath.Join("a", "b", "world.txt"), files[3].Relative)
-	assert.Equal(t, filepath.Join("a", "hello.txt"), files[4].Relative)
-	assert.Equal(t, filepath.Join("databricks.yml"), files[5].Relative)
+	require.Len(t, files, 3)
+	assert.Equal(t, filepath.Join("a", "b", "world.txt"), files[0].Relative)
+	assert.Equal(t, filepath.Join("a", "hello.txt"), files[1].Relative)
+	assert.Equal(t, filepath.Join("databricks.yml"), files[2].Relative)
+}
+
+func TestFileSetListAllInRepo(t *testing.T) {
+	testFileSetAll(t, "./testdata")
+}
+
+func TestFileSetListAllInTempDir(t *testing.T) {
+	testFileSetAll(t, copyTestdata(t, "./testdata"))
 }
 
 func TestFileSetNonCleanRoot(t *testing.T) {
@@ -32,10 +37,10 @@ func TestFileSetNonCleanRoot(t *testing.T) {
 	require.NoError(t, err)
 	files, err := fileSet.All()
 	require.NoError(t, err)
-	assert.Len(t, files, 6)
+	assert.Len(t, files, 3)
 }
 
-func TestFilesetAddsCacheDirToGitIgnore(t *testing.T) {
+func TestFileSetAddsCacheDirToGitIgnore(t *testing.T) {
 	projectDir := t.TempDir()
 	fileSet, err := NewFileSet(projectDir)
 	require.NoError(t, err)
@@ -48,7 +53,7 @@ func TestFilesetAddsCacheDirToGitIgnore(t *testing.T) {
 	assert.Contains(t, string(fileBytes), ".databricks")
 }
 
-func TestFilesetDoesNotCacheDirToGitIgnoreIfAlreadyPresent(t *testing.T) {
+func TestFileSetDoesNotCacheDirToGitIgnoreIfAlreadyPresent(t *testing.T) {
 	projectDir := t.TempDir()
 	gitIgnorePath := filepath.Join(projectDir, ".gitignore")
 

libs/git/repository.go

@@ -160,6 +160,11 @@ func (r *Repository) Ignore(relPath string) (bool, error) {
 		trailingSlash = "/"
 	}
 
+	// Never ignore the root path (an unnamed path)
+	if len(parts) == 1 && parts[0] == "." {
+		return false, nil
+	}
+
 	// Walk over path prefixes to check applicable gitignore files.
 	for i := range parts {
 		prefix := path.Clean(strings.Join(parts[:i], "/"))

libs/git/testdata/.gitignore

@@ -7,3 +7,6 @@ root.*
 
 # Directory pattern.
 ignoredirectory/
+
+# Ignore dotfiles
+.*

libs/git/view_test.go

@@ -68,8 +68,15 @@ func testViewAtRoot(t *testing.T, tv testView) {
 	assert.True(t, tv.Ignore("root/foo"))
 	assert.True(t, tv.Ignore("root_double"))
 	assert.False(t, tv.Ignore("newfile"))
+	assert.True(t, tv.Ignore(".gitignore"))
+	assert.False(t, tv.Ignore("newfile.py"))
 	assert.True(t, tv.Ignore("ignoredirectory/"))
 
+	// Never ignore the root directory.
+	// This is the only path that may be checked as `.`,
+	// and would match the `.*` ignore pattern if specified.
+	assert.False(t, tv.Ignore("."))
+
 	// Nested .gitignores should not affect root.
 	assert.False(t, tv.Ignore("a.sh"))