Ignore DoesNotExist and ErrPermission in recursive ReadDir

These can occur during recursion, but are not necessarily a problem of
the ReadDir, so just assume such problematic files are not directories
and return them. The caller can then figure out whether they are even
needed at all, and an error should be returned. This allows simply
ignoring a broken symlink when it would not even be used because of its
extension.

Author: matthijskooijman

_testdata/brokensymlink

@@ -0,0 +1 @@
+nonexistent

paths.go

@@ -334,7 +334,17 @@ func (p *Path) ReadDirRecursive() (PathList, error) {
 		paths.Add(path)
 
 		if isDir, err := path.IsDirCheck(); err != nil {
-			return nil, err
+			// Do not report not exists (broken symlink) or
+			// permission errors, since then the entry
+			// *does* exist, so let our caller figure out
+			// whether these files are relevant and this is
+			// actually a problem. We cannot ignore *all*
+			// errors, since other errors during recursion
+			// (i.e. infinite recursion due to looping
+			// symlinks) should still be returned by us.
+			if !errors.Is(err, os.ErrNotExist) && !errors.Is(err, os.ErrPermission) {
+				return nil, err
+			}
 		} else if isDir {
 			subPaths, err := path.ReadDirRecursive()
 			if err != nil {

paths_test.go

@@ -111,6 +111,19 @@ func TestPath(t *testing.T) {
 	require.False(t, anotherFilePath.Exist())
 	require.True(t, anotherFilePath.NotExist())
 
+	brokenFilePath := testPath.Join("brokensymlink")
+	pathEqualsTo(t, "_testdata/brokensymlink", brokenFilePath)
+	isDir, err = brokenFilePath.IsDirCheck()
+	require.False(t, isDir)
+	require.Error(t, err)
+	require.False(t, brokenFilePath.IsDir())
+	require.False(t, brokenFilePath.IsNotDir())
+	exist, err = brokenFilePath.ExistCheck()
+	require.False(t, exist)
+	require.NoError(t, err)
+	require.False(t, brokenFilePath.Exist())
+	require.True(t, brokenFilePath.NotExist())
+
 	list, err := folderPath.ReadDir()
 	require.NoError(t, err)
 	require.Len(t, list, 4)
@@ -260,24 +273,25 @@ func TestReadDirRecursive(t *testing.T) {
 
 	list, err := testPath.ReadDirRecursive()
 	require.NoError(t, err)
-	require.Len(t, list, 16)
+	require.Len(t, list, 17)
 
 	pathEqualsTo(t, "_testdata/anotherFile", list[0])
-	pathEqualsTo(t, "_testdata/file", list[1])
-	pathEqualsTo(t, "_testdata/folder", list[2])
-	pathEqualsTo(t, "_testdata/folder/.hidden", list[3])
-	pathEqualsTo(t, "_testdata/folder/file2", list[4])
-	pathEqualsTo(t, "_testdata/folder/file3", list[5])
-	pathEqualsTo(t, "_testdata/folder/subfolder", list[6])
-	pathEqualsTo(t, "_testdata/folder/subfolder/file4", list[7])
-	pathEqualsTo(t, "_testdata/symlinktofolder", list[8])
-	pathEqualsTo(t, "_testdata/symlinktofolder/.hidden", list[9])
-	pathEqualsTo(t, "_testdata/symlinktofolder/file2", list[10])
-	pathEqualsTo(t, "_testdata/symlinktofolder/file3", list[11])
-	pathEqualsTo(t, "_testdata/symlinktofolder/subfolder", list[12])
-	pathEqualsTo(t, "_testdata/symlinktofolder/subfolder/file4", list[13])
-	pathEqualsTo(t, "_testdata/test.txt", list[14])
-	pathEqualsTo(t, "_testdata/test.txt.gz", list[15])
+	pathEqualsTo(t, "_testdata/brokensymlink", list[1])
+	pathEqualsTo(t, "_testdata/file", list[2])
+	pathEqualsTo(t, "_testdata/folder", list[3])
+	pathEqualsTo(t, "_testdata/folder/.hidden", list[4])
+	pathEqualsTo(t, "_testdata/folder/file2", list[5])
+	pathEqualsTo(t, "_testdata/folder/file3", list[6])
+	pathEqualsTo(t, "_testdata/folder/subfolder", list[7])
+	pathEqualsTo(t, "_testdata/folder/subfolder/file4", list[8])
+	pathEqualsTo(t, "_testdata/symlinktofolder", list[9])
+	pathEqualsTo(t, "_testdata/symlinktofolder/.hidden", list[10])
+	pathEqualsTo(t, "_testdata/symlinktofolder/file2", list[11])
+	pathEqualsTo(t, "_testdata/symlinktofolder/file3", list[12])
+	pathEqualsTo(t, "_testdata/symlinktofolder/subfolder", list[13])
+	pathEqualsTo(t, "_testdata/symlinktofolder/subfolder/file4", list[14])
+	pathEqualsTo(t, "_testdata/test.txt", list[15])
+	pathEqualsTo(t, "_testdata/test.txt.gz", list[16])
 
 	// Test symlink loop
 	tmp, err := MkTempDir("", "")
@@ -298,14 +312,15 @@ func TestFilterDirs(t *testing.T) {
 
 	list, err := testPath.ReadDir()
 	require.NoError(t, err)
-	require.Len(t, list, 6)
+	require.Len(t, list, 7)
 
 	pathEqualsTo(t, "_testdata/anotherFile", list[0])
-	pathEqualsTo(t, "_testdata/file", list[1])
-	pathEqualsTo(t, "_testdata/folder", list[2])
-	pathEqualsTo(t, "_testdata/symlinktofolder", list[3])
-	pathEqualsTo(t, "_testdata/test.txt", list[4])
-	pathEqualsTo(t, "_testdata/test.txt.gz", list[5])
+	pathEqualsTo(t, "_testdata/brokensymlink", list[1])
+	pathEqualsTo(t, "_testdata/file", list[2])
+	pathEqualsTo(t, "_testdata/folder", list[3])
+	pathEqualsTo(t, "_testdata/symlinktofolder", list[4])
+	pathEqualsTo(t, "_testdata/test.txt", list[5])
+	pathEqualsTo(t, "_testdata/test.txt.gz", list[6])
 
 	list.FilterDirs()
 	require.Len(t, list, 2)
@@ -318,14 +333,15 @@ func TestFilterOutDirs(t *testing.T) {
 
 	list, err := testPath.ReadDir()
 	require.NoError(t, err)
-	require.Len(t, list, 6)
+	require.Len(t, list, 7)
 
 	pathEqualsTo(t, "_testdata/anotherFile", list[0])
-	pathEqualsTo(t, "_testdata/file", list[1])
-	pathEqualsTo(t, "_testdata/folder", list[2])
-	pathEqualsTo(t, "_testdata/symlinktofolder", list[3])
-	pathEqualsTo(t, "_testdata/test.txt", list[4])
-	pathEqualsTo(t, "_testdata/test.txt.gz", list[5])
+	pathEqualsTo(t, "_testdata/brokensymlink", list[1])
+	pathEqualsTo(t, "_testdata/file", list[2])
+	pathEqualsTo(t, "_testdata/folder", list[3])
+	pathEqualsTo(t, "_testdata/symlinktofolder", list[4])
+	pathEqualsTo(t, "_testdata/test.txt", list[5])
+	pathEqualsTo(t, "_testdata/test.txt.gz", list[6])
 
 	list.FilterOutDirs()
 	require.Len(t, list, 4)