1 files changed, 21 insertions, 20 deletions
diff --git a/git/repo/fun.py b/git/repo/fun.py
index 4d852cfe..c5a8a52b 100644
--- a/git/repo/fun.py
+++ b/git/repo/fun.py
@@ -2,22 +2,18 @@
 import os
 from string import digits
 
+from git.compat import xrange
+from git.exc import WorkTreeRepositoryUnsupported
+from git.objects import Object
+from git.refs import SymbolicReference
+from git.util import hex_to_bin, bin_to_hex, decygpath
 from gitdb.exc import (
     BadObject,
     BadName,
 )
-from git.refs import SymbolicReference
-from git.objects import Object
-from gitdb.util import (
-    join,
-    isdir,
-    isfile,
-    dirname,
-    hex_to_bin,
-    bin_to_hex
-)
-from git.exc import WorkTreeRepositoryUnsupported
-from git.compat import xrange
+
+import os.path as osp
+from git.cmd import Git
 
 
 __all__ = ('rev_parse', 'is_git_dir', 'touch', 'find_git_dir', 'name_to_object', 'short_to_long', 'deref_tag',
@@ -38,13 +34,15 @@ def is_git_dir(d):
             but at least clearly indicates that we don't support it.
             There is the unlikely danger to throw if we see directories which just look like a worktree dir,
             but are none."""
-    if isdir(d):
-        if isdir(join(d, 'objects')) and isdir(join(d, 'refs')):
-            headref = join(d, 'HEAD')
-            return isfile(headref) or \
-                (os.path.islink(headref) and
+    if osp.isdir(d):
+        if osp.isdir(osp.join(d, 'objects')) and osp.isdir(osp.join(d, 'refs')):
+            headref = osp.join(d, 'HEAD')
+            return osp.isfile(headref) or \
+                (osp.islink(headref) and
                  os.readlink(headref).startswith('refs'))
-        elif isfile(join(d, 'gitdir')) and isfile(join(d, 'commondir')) and isfile(join(d, 'gitfile')):
+        elif (osp.isfile(osp.join(d, 'gitdir')) and
+              osp.isfile(osp.join(d, 'commondir')) and
+              osp.isfile(osp.join(d, 'gitfile'))):
             raise WorkTreeRepositoryUnsupported(d)
     return False
 
@@ -62,8 +60,11 @@ def find_git_dir(d):
     else:
         if content.startswith('gitdir: '):
             path = content[8:]
-            if not os.path.isabs(path):
-                path = join(dirname(d), path)
+            if Git.is_cygwin():
+                ## Cygwin creates submodules prefixed with `/cygdrive/...` suffixes.
+                path = decygpath(path)
+            if not osp.isabs(path):
+                path = osp.join(osp.dirname(d), path)
             return find_git_dir(path)
     # end handle exception
     return None