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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Incorrect return type hint in `SymbolicReference.reference` leads to mypy errors","articleBody":"Since GitPython 3.1.45 was released, we've had `mypy` reporting pre-checkin errors for code that has been stable and functional for years:\n```\nerror: \"SymbolicReference\" has no attribute \"checkout\"  [attr-defined]\nerror: \"SymbolicReference\" has no attribute \"tracking_branch\"  [attr-defined]\nerror: \"SymbolicReference\" has no attribute \"tracking_branch\"  [attr-defined]\n```\n\nThe code failing `mypy` checks is doing things like getting the active branch, so we can switch back to it after doing other stuff:\n```\n    @contextmanager\n    def checkout(self, branch: Branch) -\u003e typing.Generator[None]:\n        new_branch = self.api.create_head(branch.name)\n        current = self.api.head.ref\n        try:\n            new_branch.checkout()\n            yield\n        finally:\n            current.checkout()\n```\n\n... or ensuring that the active branch has a remote tracking branch set:\n```\n    tracking_branch = repo.head.reference.tracking_branch()\n    if tracking_branch is None:\n        raise GitConfigException(\n            'Error: Upstream branch not set; use \"git branch '\n            '--set-upstream-to=\u003cremote/branch\u003e\" to fix.'\n        )\n    if tracking_branch.remote_name == \".\":\n        raise GitConfigException(\n            'Error: Upstream branch is local rather than remote; use \"git '\n            'branch --set-upstream-to=\u003cremote/branch\u003e\" to fix.'\n        )\n``` \n\nThe immediate cause of these new `mypy` errors appears to be [this commit](https://github.com/gitpython-developers/GitPython/commit/94151aa2ca9f16491a0cf2344b4daa8bf7b41d70#diff-72d42177f0e8535634711b5de0390d5bc81dbedab1fbac6547e5b9ab3b03eb9aL52), which added a new type hint for the return value of `SymbolicReference.reference`:\n```\n    @property\n    def reference(self) -\u003e \"SymbolicReference\":\n        return self._get_reference()\n```\n\nIn manual testing I've found that the `reference` method doesn't actually return a `SymbolicReference` object when the the symbolic reference is `HEAD`. Instead, a `Head` object is returned:\n```\n\u003e\u003e\u003e import git\n\u003e\u003e\u003e git.__version__\n'3.1.45'\n\u003e\u003e\u003e testrepo = git.repo.Repo.init(\".\")\n\u003e\u003e\u003e type(testrepo.head)\n\u003cclass 'git.refs.head.HEAD'\u003e\n\u003e\u003e\u003e type(testrepo.head.ref)\n\u003cclass 'git.refs.head.Head'\u003e\n\u003e\u003e\u003e testrepo.head.ref.tracking_branch()\n\u003cgit.RemoteReference \"refs/remotes/./master\"\u003e\n\u003e\u003e\u003e testrepo.head.ref.checkout()\n\u003cgit.Head \"refs/heads/bar\"\u003e\n```","author":{"url":"https://github.com/dvanderveer","@type":"Person","name":"dvanderveer"},"datePublished":"2025-08-08T20:57:57.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/2066/GitPython/issues/2066"}