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Adding a classmethod to TypedDict with "# type: ignore" crashes mypy #9820
Description
Crash Report / To Reproduce
I know that currently allowing adding class methods to TypedDict is not on the priority (#5653),
so I tried to use it anyway with # type: ignore.
from __future__ import annotations
from typing import Literal, Mapping, Optional, TypedDict
import trafaret as t # https://github.com/Deepwalker/trafaret
__all__ = (
'HardwareMetadata',
)
class HardwareMetadata(TypedDict):
status: Literal["healthy", "degraded", "offline", "unavailable"]
status_info: Optional[str]
metadata: Mapping[str, str]
@classmethod # type: ignore
def check(cls, value: Any) -> HardwareMetadata:
try:
return t.Dict({
t.Key('status'): t.Enum("healthy", "degraded", "offline", "unavailable"),
t.Key('status_info'): t.Null | t.String,
t.Key('metadata'): t.Mapping(t.String, t.String),
}).check(value)
except t.DataError as e:
raise ValueError("The give value does not conform with the target typed dict.", e.as_dict())I'm referring this as HardwareMetadata.check(...) in another module.
My intention is to validate JSON-like semi-structured data at runtime and use it safely when passing around the codebase with static type check.
Then, running mypy began to crash.
I think it should not crash anyway even though it does not allow this pattern.
Traceback
/home/joongi/backend.ai-dev/common-2009/src/ai/backend/common/types.py: error: INTERNAL ERROR -- Please try using mypy master on Github:
https://mypy.rtfd.io/en/latest/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 0.790
Traceback (most recent call last):
File "/home/joongi/.pyenv/versions/3.8.5/lib/python3.8/runpy.py", line 194, in _run_module_as_main
return _run_code(code, main_globals, None,
File "/home/joongi/.pyenv/versions/3.8.5/lib/python3.8/runpy.py", line 87, in _run_code
exec(code, run_globals)
File "mypy/build.py", line 1922, in wrap_context
File "mypy/semanal_main.py", line 360, in check_type_arguments
File "mypy/nodes.py", line 295, in accept
File "mypy/semanal_typeargs.py", line 39, in visit_mypy_file
File "mypy/traverser.py", line 35, in visit_mypy_file
File "mypy/nodes.py", line 940, in accept
File "mypy/semanal_typeargs.py", line 50, in visit_class_def
File "mypy/mixedtraverser.py", line 28, in visit_class_def
File "mypy/traverser.py", line 71, in visit_class_def
File "mypy/nodes.py", line 1005, in accept
File "mypy/semanal_typeargs.py", line 54, in visit_block
File "mypy/traverser.py", line 39, in visit_block
File "mypy/nodes.py", line 767, in accept
File "mypy/traverser.py", line 76, in visit_decorator
File "mypy/nodes.py", line 677, in accept
File "mypy/traverser.py", line 54, in visit_func_def
File "mypy/semanal_typeargs.py", line 46, in visit_func
File "mypy/mixedtraverser.py", line 23, in visit_func
File "mypy/mixedtraverser.py", line 91, in visit_optional_type
File "mypy/types.py", line 1098, in accept
File "mypy/typetraverser.py", line 52, in visit_callable_type
File "mypy/types.py", line 794, in accept
File "mypy/semanal_typeargs.py", line 70, in visit_instance
AttributeError: attribute 'defn' of 'TypeInfo' undefined
/home/joongi/backend.ai-dev/common-2009/src/ai/backend/common/types.py: : note: use --pdb to drop into pdb
Your Environment
- Mypy version used: 0.790
- Mypy command-line flags:
python -m mypy src/ai/backend tests --show-traceback- Note:
ai.backendis the namespace pkg.
- Note:
- Mypy configuration options from
mypy.ini(and other config files): I have the following insetup.cfg:
[mypy]
ignore_missing_imports = true
namespace_packages = true
- Python version used: Python 3.8.5
- Operating system and version: Ubuntu 20.04
Reacted by Luo Chen
Activity
achimnol commentedon Dec 18, 2020
Rewriting the type definitions like this:
"fixes" the crash, but I need to put
# type: ignorewhenever I callHardwareMetadata.check().achimnol commentedon Dec 18, 2020
It seems that the current "correct" workaround is to just separate the check method as an independent function.
I understand that TypedDict is not a real type but more like a meta-type, which leads to the design decision not allowing method addition.
Would there be good alternative ways to combine runtime input validation and static typing for semi-structured data?
achimnol commentedon Dec 18, 2020
For instance, maybe we could just extend mypy to recognize trafaret validators as static type definitions of corresponding Python types. Though, I don't know the details about mypy extensions, so I'm not sure that this would be a good approach for this issue.
achimnol commentedon Dec 19, 2020
I ended up combining the original TypedDict definition and
check_typed_dict()from typeguard for runtime input validation for now. It seems to validate my above case very well, includingLiteralchoices.gaozhidf commentedon Dec 8, 2024
u can try about
Self(ref: https://docs.python.org/3/library/typing.html#typing.Self)