gh-20476: Fix AssertionError (too many plugin hook passes) on dataclass attribute redefinition #20521
+56
−2
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Fixes gh-20476
There was a crash in the dataclass plugin when an attribute was re-defined, to wit:
AssertionError: Internal error: too many class plugin hook passesfrom the repro script in the issue. Changed a couple things here:mypy/plugins/dataclasses.pydetect re-defined attrs. If so, the plugin now skips the transformation for that attribute, allowing the reporting of a [no-redef] error instead of triggering a crash.mypy/semanal_main.pyto break out of potential infinite loops caused by class plugin hooks that don't reach a stable state.And added a test! All other tests pass as well.