[dataclass_transform] minimal implementation of dataclass_transform #14523
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… dataclasses plugin This is a very simple first step to implementing [PEP 0681](https://peps.python.org/pep-0681/#decorator-function-example), which will allow MyPy to recognize user-defined types that behave similarly to dataclasses. This initial implementation is very limited: we only support decorator-style use of `typing.dataclass_transform` and do not support passing additional options to the transform (such as `freeze` or `init`). Within MyPy, we add a new `is_dataclass_transform` field to `FuncBase` which is populated during semantic analysis. When we check for plugin hooks later, we add new special cases to use the dataclasses plugin if a class decorator is marked with `is_dataclass_transform`. Ideally we would use a proper plugin API; the hacky special case here can be replaced in subsequent iterations.
wesleywright
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Jan 25, 2023
| ) | ||
| from mypy.plugin import CheckerPluginInterface, ClassDefContext, SemanticAnalyzerPluginInterface | ||
| from mypy.semanal import ALLOW_INCOMPATIBLE_OVERRIDE, set_callable_name | ||
| from mypy.semanal_shared import ALLOW_INCOMPATIBLE_OVERRIDE, set_callable_name |
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this move was needed to avoid a cyclic dependency between semanal.py and plugins/common.py
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I see only |
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I think this is a gap currently, thanks for the catch (this is my first PR adding this kind of feature haha) |
wesleywright
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Jan 25, 2023
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| class list(Generic[_T], Sequence[_T]): | ||
| def __contains__(self, item: object) -> int: pass | ||
| def __getitem__(self, key: int) -> _T: pass | ||
| def __iter__(self) -> Iterator[_T]: pass | ||
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needed to use dataclasses.pyi and typing-full.pyi at the same time in a test case
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JukkaL
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Jan 26, 2023
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Thanks for the PR! This is solid basic implementation. You'll need to fix flake8, otherwise everything looks good.
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According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
hauntsaninja
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Jan 26, 2023
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Thanks, this looks great. Let's get this into 1.0. It's not complete, but it will result in strictly fewer errors for users of PEP 681 than current master.
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Jan 26, 2023
…ython#14523) This is a very simple first step to implementing [PEP 0681](https://peps.python.org/pep-0681/#decorator-function-example), which will allow MyPy to recognize user-defined types that behave similarly to dataclasses. This initial implementation is very limited: we only support decorator-style use of `typing.dataclass_transform` and do not support passing additional options to the transform (such as `freeze` or `init`). Within MyPy, we add a new `is_dataclass_transform` field to `FuncBase` which is populated during semantic analysis. When we check for plugin hooks later, we add new special cases to use the existing dataclasses plugin if a class decorator is marked with `is_dataclass_transform`. Ideally we would use a proper plugin API; the hacky special case here can be replaced in subsequent iterations. Co-authored-by: Wesley Wright <[email protected]>
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Jan 29, 2023
…#14532) This is a very simple first step to implementing [PEP 0681](https://peps.python.org/pep-0681/#decorator-function-example), which will allow MyPy to recognize user-defined types that behave similarly to dataclasses. This initial implementation is very limited: we only support decorator-style use of `typing.dataclass_transform` and do not support passing additional options to the transform (such as `freeze` or `init`). Within MyPy, we add a new `is_dataclass_transform` field to `FuncBase` which is populated during semantic analysis. When we check for plugin hooks later, we add new special cases to use the existing dataclasses plugin if a class decorator is marked with `is_dataclass_transform`. Ideally we would use a proper plugin API; the hacky special case here can be replaced in subsequent iterations. Co-authored-by: Wesley Collin Wright <[email protected]> Co-authored-by: Wesley Wright <[email protected]>
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This is a very simple first step to implementing PEP 0681, which will allow MyPy to recognize user-defined types that behave similarly to dataclasses.
This initial implementation is very limited: we only support decorator-style use of
typing.dataclass_transformand do not support passing additional options to the transform (such asfreezeorinit).Within MyPy, we add a new
is_dataclass_transformfield toFuncBasewhich is populated during semantic analysis. When we check for plugin hooks later, we add new special cases to use the existing dataclasses plugin if a class decorator is marked withis_dataclass_transform. Ideally we would use a proper plugin API; the hacky special case here can be replaced in subsequent iterations.