[mypyc] Record MRO ancestor modules as deps of subclass-defining modules#21743
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Fixes python#21742 Mypy's incremental system only recompiles a module when a recorded dependency changes, and a dependency edge to an ancestor's module is created in cases such as an explicit import or a checked expression whose type references that ancestor. A bare subclass definition produces neither, so the transitive ancestors never enter the module's dependency graph. The goal of this PR is to make the dependency graph reflect what the generated C actually depends on. When compiling with mypyc, a module that defines a class now records the modules defining every ancestor in that class's MRO as indirect dependencies, so an ancestor's interface change reaches the subclass-defining module directly.
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According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅ |
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Fixes #21742
Mypy's incremental system only recompiles a module when a recorded dependency changes, and a dependency edge to an ancestor's module is created in cases such as an explicit import or a checked expression whose type references that ancestor. A bare subclass definition produces neither, so the transitive ancestors never enter the module's dependency graph.
The goal of this PR is to make the dependency graph reflect what the generated C actually depends on. When compiling with mypyc, a module that defines a class now records the modules defining every ancestor in that class's MRO as indirect dependencies, so an ancestor's interface change reaches the subclass-defining module directly.