Fine-grained: Support NewType and reset subtype caches #4656
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NewType work highlighted an issue with subtype caches with stale information leaking, and this fixes that issue as well. We reset the subtype cache in two places: * When calculating the MRO; we reset caches of all base classes as well. * When merging a new version of a TypeInfo, which may have a different MRO; we reset all caches of base classes in the old MRO, as they might no longer be supertypes.
msullivan
approved these changes
Mar 1, 2018
| @@ -2122,6 +2127,7 @@ def calculate_mro(self) -> None: | |||
| self.is_enum = self._calculate_is_enum() | |||
| # The property of falling back to Any is inherited. | |||
| self.fallback_to_any = any(baseinfo.fallback_to_any for baseinfo in self.mro) | |||
| self.reset_subtype_cache() | |||
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I don't fully understand why this is necessary (though it certainly isn't /wrong/). Adding a new subclass shouldn't invalidate any of the caches, since they store only positive information?
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I think that some changes in generic base classes may require this. Say, originally the base class was C[A] and after update it is C[B]. This would change the subtype relation even though the MRO is unchanged. If we are doing a refresh of the class there would be no AST merge so without this the subtype cache would not get emptied.
carljm
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Mar 6, 2018
* master: New files shouldn't trigger a coarse-grained rebuild in fg cache mode (python#4669) Bump version to 0.580-dev Update revision history for 0.570 (python#4662) Fine-grained: Fix crashes when refreshing synthetic types (python#4667) Fine-grained: Support NewType and reset subtype caches (python#4656) Fine-grained: Detect changes in additional TypeInfo attributes (python#4659) Fine-grained: Apply semantic analyzer patch callbacks (python#4658) Optimize fine-grained update by using Graph as the cache (python#4622) Cleanup check_reverse_op_method (python#4017) Fine-grained: Fix AST merge issues (python#4652) Optionally check that we don't have duplicate nodes after AST merge (python#4647)
yedpodtrzitko
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Mar 15, 2018
NewType work highlighted an issue with subtype caches with stale information leaking, and this fixes that issue as well. We reset the subtype cache in two places: * When calculating the MRO; we reset caches of all base classes as well. * When merging a new version of a TypeInfo, which may have a different MRO; we reset all caches of base classes in the old MRO, as they might no longer be supertypes.
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NewType work highlighted an issue with subtype caches with stale
information leaking, and this fixes that issue as well. We reset the
subtype cache in two places:
When calculating the MRO; we reset caches of all base classes as
well.
When merging a new version of a TypeInfo, which may have a
different MRO; we reset all caches of base classes in the old
MRO, as they might no longer be supertypes.