worktrees: make non-packed refs also work correctly.

Turns out aec58a9 did the right thing for /packed/ refs, but didn't work
correctly on /unpacked/ refs.  So this patch gives unpacked refs the
same treatment.

Without the fix here, the test added will cause this traceback:

======================================================================
ERROR: Check that we find .git as a worktree file and find the worktree
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/pjones/devel/github.com/GitPython/git/test/lib/helper.py", line 92, in wrapper
    return func(self, path)
  File "/home/pjones/devel/github.com/GitPython/git/test/test_repo.py", line 938, in test_git_work_tree_dotgit
    self.assertIsInstance(repo.heads['aaaaaaaa'], Head)
  File "/home/pjones/devel/github.com/GitPython/git/util.py", line 893, in __getitem__
    raise IndexError("No item found with id %r" % (self._prefix + index))
IndexError: No item found with id 'aaaaaaaa'

Woops.

Things I've learned:
- test_remote doesn't work currently if you start on a branch.  I think
  it never did?
- Because of 346424da, all *sorts* of stuff in the test suite doesn't
  work if you name your development branch "packed-refs"
  (This seems like a bug...)

Signed-off-by: Peter Jones <pjones@redhat.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/git/repo/base.py b/git/repo/base.py
index 28bb2a5d..d607deee 100644
--- a/git/repo/base.py
+++ b/git/repo/base.py
@@ -74,6 +74,7 @@ class Repo(object):
     working_dir = None
     _working_tree_dir = None
     git_dir = None
+    _common_dir = None
 
     # precompiled regex
     re_whitespace = re.compile(r'\s+')
@@ -169,17 +170,23 @@ class Repo(object):
             # lets not assume the option exists, although it should
             pass
 
+        try:
+            common_dir = open(osp.join(self.git_dir, 'commondir'), 'rt').readlines()[0].strip()
+            self._common_dir = osp.join(self.git_dir, common_dir)
+        except (OSError, IOError):
+            self._common_dir = None
+
         # adjust the wd in case we are actually bare - we didn't know that
         # in the first place
         if self._bare:
             self._working_tree_dir = None
         # END working dir handling
 
-        self.working_dir = self._working_tree_dir or self.git_dir
+        self.working_dir = self._working_tree_dir or self.common_dir
         self.git = self.GitCommandWrapperType(self.working_dir)
 
         # special handling, in special times
-        args = [osp.join(self.git_dir, 'objects')]
+        args = [osp.join(self.common_dir, 'objects')]
         if issubclass(odbt, GitCmdObjectDB):
             args.append(self.git)
         self.odb = odbt(*args)
@@ -237,6 +244,13 @@ class Repo(object):
         return self._working_tree_dir
 
     @property
+    def common_dir(self):
+        """:return: The git dir that holds everything except possibly HEAD,
+        FETCH_HEAD, ORIG_HEAD, COMMIT_EDITMSG, index, and logs/ .
+        """
+        return self._common_dir or self.git_dir
+
+    @property
     def bare(self):
         """:return: True if the repository is bare"""
         return self._bare
@@ -574,7 +588,7 @@ class Repo(object):
         :note:
             The method does not check for the existence of the paths in alts
             as the caller is responsible."""
-        alternates_path = osp.join(self.git_dir, 'objects', 'info', 'alternates')
+        alternates_path = osp.join(self.common_dir, 'objects', 'info', 'alternates')
         if not alts:
             if osp.isfile(alternates_path):
                 os.remove(alternates_path)
@@ -932,7 +946,7 @@ class Repo(object):
             * All remaining keyword arguments are given to the git-clone command
 
         :return: ``git.Repo`` (the newly cloned repo)"""
-        return self._clone(self.git, self.git_dir, path, type(self.odb), progress, **kwargs)
+        return self._clone(self.git, self.common_dir, path, type(self.odb), progress, **kwargs)
 
     @classmethod
     def clone_from(cls, url, to_path, progress=None, env=None, **kwargs):