[ty] Recover from dynamic class code generator cycles#26167
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charliermarsh merged 2 commits intoJun 20, 2026
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Checking a self-referential dynamically-created class (e.g. the fuzzer-found
`type("T", NamedTuple("T", [("", "T")]), {})`) panicked with `dependency graph
cycle when querying code_generator_of_dynamic_class(...)`: the query re-enters
itself via `iter_mro` -> `deferred_explicit_bases` -> ... .
Its static-class sibling `code_generator_of_static_class` already recovers from
such cycles with `cycle_initial=|_, _, _| None`; apply the same recovery to the
dynamic-class query so a cycle resolves to "no code generator" instead of
panicking.
Fixes astral-sh/ty#3720.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
Typing conformance resultsNo changes detected ✅Current numbersThe percentage of diagnostics emitted that were expected errors held steady at 94.37%. The percentage of expected errors that received a diagnostic held steady at 89.00%. The number of fully passing files held steady at 94/134. |
Memory usage reportMemory usage unchanged ✅ |
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code_generator_of_dynamic_class
charliermarsh
approved these changes
Jun 20, 2026
code_generator_of_dynamic_class
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Summary
Determining whether a dynamically created class has dataclass- or named-tuple-like behavior can re-enter the same query while resolving a self-referential base:
Prior to this change,
code_generator_of_dynamic_classhad no cycle recovery, so this input panicked withdependency graph cycle. This applies the same recovery used for static classes, treating a cyclic result as having no code generator rather than panicking.Closes astral-sh/ty#3720.