A Git instance produced by pickle deserialization always has a version_info of None. This prevents version information from being accessed through version_info. It also causes the version_info property not to satisfy its type annotation as a tuple of ints (independently of #1830). This is the case whether or not version_info has been accessed on the original instance before it was pickled:
>>> import pickle, git
>>> g = git.Git()
>>> g.version_info
(2, 34, 1)
>>> g2 = pickle.loads(pickle.dumps(g))
>>> g2.version_info
>>>
>>> import pickle, git
>>> g = git.Git()
>>> g2 = pickle.loads(pickle.dumps(g))
>>> g2.version_info
>>>
This is due to an inconsistency in how the state of not yet having computed version_info is represented in the backing attribute _version_info:
Git uses LazyMixin caching for _version_info, which treats the attribute as uncomputed when absent and computed when present.Git defines __getstate__ and __setstate__ for pickling and unpickling to represent state pickling does not preserve by setting attributes to None.
The _version_info attribute is set to None on a Git object created by unpickling, so when accessing the version_info property delegates to the _version_info attribute, its value of None is returned and the if attr == "_version_info" logic in the _set_cache_ method (inherited from LazyMixin and overridden) is never run.
The intention is that an unpickled Git object have version_info in the uncomputed state. This works for the other two excluded attributes, which use the same None convention as in the __getstate__ and __setstate__ implementations, and which do not use any LazyMixin functionality for their caching:
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_excluded_ = ("cat_file_all", "cat_file_header", "_version_info") |
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def __getstate__(self) -> Dict[str, Any]: |
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return slots_to_dict(self, exclude=self._excluded_) |
|
|
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def __setstate__(self, d: Dict[str, Any]) -> None: |
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dict_to_slots_and__excluded_are_none(self, d, excluded=self._excluded_) |
Unlike _version_info, which is managed by _set_cache_, the cat_file_all and cat_file_header attributes are initialized to None in Git.__init__:
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# Cached command slots |
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self.cat_file_header: Union[None, TBD] = None |
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self.cat_file_all: Union[None, TBD] = None |
This is natural to fix at the same time as #1829, because a fix for that should change the way caching works. LazyMixin caching supports attributes that are computed once and never become stale, so version_info/_version_info should implement caching in a different way to fix #1829, and that can fix this too if consistent with __getstate__/__setstate__.
A
Gitinstance produced by pickle deserialization always has aversion_infoofNone. This prevents version information from being accessed throughversion_info. It also causes theversion_infoproperty not to satisfy its type annotation as a tuple ofints (independently of #1830). This is the case whether or notversion_infohas been accessed on the original instance before it was pickled:This is due to an inconsistency in how the state of not yet having computed
version_infois represented in the backing attribute_version_info:GitusesLazyMixincaching for_version_info, which treats the attribute as uncomputed when absent and computed when present.Gitdefines__getstate__and__setstate__for pickling and unpickling to represent state pickling does not preserve by setting attributes toNone.The
_version_infoattribute is set toNoneon aGitobject created by unpickling, so when accessing theversion_infoproperty delegates to the_version_infoattribute, its value ofNoneis returned and theif attr == "_version_info"logic in the_set_cache_method (inherited fromLazyMixinand overridden) is never run.The intention is that an unpickled
Gitobject haveversion_infoin the uncomputed state. This works for the other two excluded attributes, which use the sameNoneconvention as in the__getstate__and__setstate__implementations, and which do not use anyLazyMixinfunctionality for their caching:GitPython/git/cmd.py
Line 315 in afa5754
GitPython/git/cmd.py
Lines 319 to 323 in afa5754
Unlike
_version_info, which is managed by_set_cache_, thecat_file_allandcat_file_headerattributes are initialized toNoneinGit.__init__:GitPython/git/cmd.py
Lines 786 to 788 in afa5754
This is natural to fix at the same time as #1829, because a fix for that should change the way caching works.
LazyMixincaching supports attributes that are computed once and never become stale, soversion_info/_version_infoshould implement caching in a different way to fix #1829, and that can fix this too if consistent with__getstate__/__setstate__.