Mypyc crashes on conditionally-defined class
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crash
topic-mypyc
- Dominant language
- Python
- Stars
- 20.6k
- Forks
- 3.3k
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Description
To Reproduce
if True:
class A:
pass
(This example is silly, but a real use case would be defining a protocol inside a TYPE_CHECKING block.)
Actual Behavior
File "mypy/mypy/nodes.py", line 1141, in accept
return visitor.visit_class_def(self)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "mypy/mypyc/irbuild/visitor.py", line 167, in visit_class_def
transform_class_def(self.builder, cdef)
File "mypy/mypyc/irbuild/classdef.py", line 88, in transform_class_def
ir = builder.mapper.type_to_ir[cdef.info]
~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^
asdf.py:2: KeyError: <TypeInfo asdf.A>
mypyc --version
mypy 1.6.0+dev.89ad125fa5a31a7c82f267e957d3c94da6b52f61
(compiled: no)
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the conditional class example with mypyc, then read mypy/mypyc/irbuild/visitor.py and mypy/mypyc/irbuild/classdef.py around visit_class_def and transform_class_def. Trace why the conditionally defined TypeInfo is absent from type_to_ir; done means the example no longer raises the reported KeyError and the behavior is covered by regression testing.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 42/100