Fixes creating a Repo for a submodule

Fixes gitpython-developers#155.

Author: remram44

git/repo/base.py

@@ -32,6 +32,7 @@
 from fun import (
                     rev_parse,
                     is_git_dir,
+                    find_git_dir,
                     touch
                 )
 
@@ -108,8 +109,8 @@ def __init__(self, path=None, odbt = DefaultDBType):
                 self.git_dir = curpath
                 self._working_tree_dir = os.path.dirname(curpath)
                 break
-            gitpath = join(curpath, '.git')
-            if is_git_dir(gitpath):
+            gitpath = find_git_dir(join(curpath, '.git'))
+            if gitpath is not None:
                 self.git_dir = gitpath
                 self._working_tree_dir = curpath
                 break
@@ -119,7 +120,7 @@ def __init__(self, path=None, odbt = DefaultDBType):
         # END while curpath
 
         if self.git_dir is None:
-           raise InvalidGitRepositoryError(epath)
+            raise InvalidGitRepositoryError(epath)
 
         self._bare = False
         try:

git/repo/fun.py

@@ -7,6 +7,7 @@
                             join,
                             isdir, 
                             isfile,
+                            dirname,
                             hex_to_bin, 
                             bin_to_hex
                         )
@@ -31,6 +32,18 @@ def is_git_dir(d):
     return False
 
 
+def find_git_dir(d):
+    if is_git_dir(d):
+        return d
+    elif isfile(d):
+        with open(d) as fp:
+            content = fp.read().rstrip()
+        if content.startswith('gitdir: '):
+            d = join(dirname(d), content[8:])
+            return find_git_dir(d)
+    return None
+
+
 def short_to_long(odb, hexsha):
     """:return: long hexadecimal sha1 from the given less-than-40 byte hexsha
         or None if no candidate could be found.