filesystem: handle missing dir in 'ReadDirRecursive()'

If 'ReadDirRecursive()' receives a non-existent root path, the initial
'os.ReadDir()' throws a ENOENT error. Handle this case more gracefully
(i.e., without error) by returning an empty entry list with no error if the
we should exit gracefully if the error from 'os.ReadDir()' is
'os.ErrNotExist' (corresponding to ENOENT).

Signed-off-by: Victoria Dye <vdye@github.com>

Author: vdye

internal/common/filesystem.go

@@ -215,7 +215,13 @@ func (f *fileSystem) ReadDirRecursive(path string, depth int, strictDepth bool)
 
 	dirEntries, err := os.ReadDir(path)
 	if err != nil {
-		return nil, err
+		if errors.Is(err, os.ErrNotExist) {
+			// We tried to read the directory, but it doesn't exist - return
+			// empty result.
+			return []ReadDirEntry{}, nil
+		} else {
+			return nil, err
+		}
 	}
 
 	entries := utils.Map(dirEntries, mapDirEntry(path))