Read git sha from packed-refs file after a git-gcpacked-refs

Fixes GH-758 GH-709

1 files changed, 21 insertions, 1 deletions

diff --git a/raven/versioning.py b/raven/versioning.py
index c36b719..993a238 100644
--- a/raven/versioning.py
+++ b/raven/versioning.py
@@ -28,8 +28,9 @@ def fetch_git_sha(path, head=None):
             head = text_type(fp.read()).strip()
 
         if head.startswith('ref: '):
+            head = head[5:]
             revision_file = os.path.join(
-                path, '.git', *head.rsplit(' ', 1)[-1].split('/')
+                path, '.git', *head.split('/')
             )
         else:
             return head
@@ -40,6 +41,25 @@ def fetch_git_sha(path, head=None):
         if not os.path.exists(os.path.join(path, '.git')):
             raise InvalidGitRepository(
                 '%s does not seem to be the root of a git repository' % (path,))
+
+        # Check for our .git/packed-refs' file since a `git gc` may have run
+        # https://git-scm.com/book/en/v2/Git-Internals-Maintenance-and-Data-Recovery
+        packed_file = os.path.join(path, '.git', 'packed-refs')
+        if os.path.exists(packed_file):
+            with open(packed_file, 'r') as fh:
+                for line in fh:
+                    line = line.rstrip()
+                    if not line:
+                        continue
+                    if line[:1] in ('#', '^'):
+                        continue
+                    try:
+                        revision, ref = line.split(' ', 1)
+                    except ValueError:
+                        continue
+                    if ref == head:
+                        return text_type(revision)
+
         raise InvalidGitRepository(
             'Unable to find ref to head "%s" in repository' % (head,))