1 files changed, 61 insertions, 13 deletions

diff --git a/git/compat.py b/git/compat.py
index de8a238b..187618a2 100644
--- a/git/compat.py
+++ b/git/compat.py
@@ -11,40 +11,84 @@ import locale
 import os
 import sys
 
-
 from gitdb.utils.encoding import (
     force_bytes,     # @UnusedImport
     force_text       # @UnusedImport
 )
 
+# typing --------------------------------------------------------------------
+
+from typing import (
+    Any,
+    AnyStr,
+    Dict,
+    IO,
+    Optional,
+    Tuple,
+    Type,
+    Union,
+    overload,
+)
+from git.types import TBD
+
+# ---------------------------------------------------------------------------
+
 
-is_win = (os.name == 'nt')
+is_win = (os.name == 'nt')  # type: bool
 is_posix = (os.name == 'posix')
 is_darwin = (os.name == 'darwin')
 defenc = sys.getfilesystemencoding()
 
 
-def safe_decode(s):
+@overload
+def safe_decode(s: None) -> None: ...
+
+
+@overload
+def safe_decode(s: AnyStr) -> str: ...
+
+
+def safe_decode(s: Union[AnyStr, None]) -> Optional[str]:
     """Safely decodes a binary string to unicode"""
     if isinstance(s, str):
         return s
     elif isinstance(s, bytes):
         return s.decode(defenc, 'surrogateescape')
-    elif s is not None:
+    elif s is None:
+        return None
+    else:
         raise TypeError('Expected bytes or text, but got %r' % (s,))
 
 
-def safe_encode(s):
-    """Safely decodes a binary string to unicode"""
+@overload
+def safe_encode(s: None) -> None: ...
+
+
+@overload
+def safe_encode(s: AnyStr) -> bytes: ...
+
+
+def safe_encode(s: Optional[AnyStr]) -> Optional[bytes]:
+    """Safely encodes a binary string to unicode"""
     if isinstance(s, str):
         return s.encode(defenc)
     elif isinstance(s, bytes):
         return s
-    elif s is not None:
+    elif s is None:
+        return None
+    else:
         raise TypeError('Expected bytes or text, but got %r' % (s,))
 
 
-def win_encode(s):
+@overload
+def win_encode(s: None) -> None: ...
+
+
+@overload
+def win_encode(s: AnyStr) -> bytes: ...
+
+
+def win_encode(s: Optional[AnyStr]) -> Optional[bytes]:
     """Encode unicodes for process arguments on Windows."""
     if isinstance(s, str):
         return s.encode(locale.getpreferredencoding(False))
@@ -52,16 +96,20 @@ def win_encode(s):
         return s
     elif s is not None:
         raise TypeError('Expected bytes or text, but got %r' % (s,))
+    return None
 
 
-def with_metaclass(meta, *bases):
+# type: ignore ## mypy cannot understand dynamic class creation
+def with_metaclass(meta: Type[Any], *bases: Any) -> TBD:
     """copied from https://github.com/Byron/bcore/blob/master/src/python/butility/future.py#L15"""
-    class metaclass(meta):
+
+    class metaclass(meta):  # type: ignore
         __call__ = type.__call__
-        __init__ = type.__init__
+        __init__ = type.__init__    # type: ignore
 
-        def __new__(cls, name, nbases, d):
+        def __new__(cls, name: str, nbases: Optional[Tuple[int, ...]], d: Dict[str, Any]) -> TBD:
             if nbases is None:
                 return type.__new__(cls, name, (), d)
             return meta(name, bases, d)
-    return metaclass(meta.__name__ + 'Helper', None, {})
+
+    return metaclass(meta.__name__ + 'Helper', None, {})  # type: ignore