Merge support for Repo.discover.

dulwich/repo.py

@@ -678,6 +678,26 @@ class Repo(BaseRepo):
         self.hooks['commit-msg'] = CommitMsgShellHook(self.controldir())
         self.hooks['post-commit'] = PostCommitShellHook(self.controldir())
 
+    @classmethod
+    def discover(cls, start='.'):
+        """Iterate parent directories to discover a repository
+
+        Return a Repo object for the first parent directory that looks like a
+        Git repository.
+
+        :param start: The directory to start discovery from (defaults to '.')
+        """
+        remaining = True
+        path = os.path.abspath(start)
+        while remaining:
+            try:
+                return cls(path)
+            except NotGitRepository:
+                path, remaining = os.path.split(path)
+        raise NotGitRepository(
+            "No git repository was found at %(path)s" % dict(path=start)
+        )
+
     def controldir(self):
         """Return the path of the control directory."""
         return self._controldir

dulwich/tests/test_repository.py

@@ -35,6 +35,7 @@ from dulwich.object_store import (
     )
 from dulwich import objects
 from dulwich.config import Config
+from dulwich.errors import NotGitRepository
 from dulwich.repo import (
     Repo,
     MemoryRepo,
@@ -765,3 +766,16 @@ class BuildRepoRootTests(TestCase):
             mode, id = tree_lookup_path(r.get_object, r[commit_sha].tree, name)
             self.assertEqual(stat.S_IFREG | 0o644, mode)
             self.assertEqual(encoding.encode('ascii'), r[id].data)
+
+    def test_discover_intended(self):
+        path = os.path.join(self._repo_dir, 'b/c')
+        r = Repo.discover(path)
+        self.assertEqual(r.head(), self._repo.head())
+
+    def test_discover_isrepo(self):
+        r = Repo.discover(self._repo_dir)
+        self.assertEqual(r.head(), self._repo.head())
+
+    def test_discover_notrepo(self):
+        with self.assertRaises(NotGitRepository):
+            Repo.discover('/')