Make configparser.RawConfigParser use SectionProxy where appropriate #1527
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This won't be necessary once python/typeshed#1527 lands.
OddBloke
changed the title
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Also relevant to getting the types in check: python/cpython#3012 |
stdlib/3/configparser.pyi
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| def items(self, *, raw: bool = ..., vars: _section = ...) -> AbstractSet[Tuple[str, SectionProxy]]: ... | ||
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| @overload | ||
| def items(self, section: str, raw: bool = ..., vars: _section = ...) -> Iterable[Tuple[str, str]]: ... |
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It actually returns a list. Any reason not to use List in the annotation?
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No reason I can think of; updated.
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I created a file Using this branch of typeshed, mypy gives me If I understand this correctly, using the current definition for SectionProxy causes Bottom line, it seems unfortunate that mypy doesn't know that |
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@reddraggone9 That is something that needs fixing, but AFAICT this PR doesn't regress that behaviour. Indeed, without this PR, I get the following output from mypy: |
| # This is incompatible with Mapping so we ignore the type. | ||
| def items(self, section: str = ..., raw: bool = ..., vars: _section = ...) -> Iterable[Tuple[str, _section]]: ... # type: ignore | ||
| @overload | ||
| def items(self, *, raw: bool = ..., vars: _section = ...) -> AbstractSet[Tuple[str, SectionProxy]]: ... |
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In general, return types that are as concrete as possible, and accept types in arguments that are as generic as possible.
This reflects the code in the cpython tree and makes the following
(valid) code type-check correctly:
```
from configparser import ConfigParser
config = ConfigParser()
config.read_dict({'section': {'key': 'false'}})
assert config['section'].getboolean('key') is False
```
Because .items() uses __getitem__ to produce second item in each tuple.
TL;DR, we're hitting python/mypy#3805 when implemented correctly as an override, and python/mypy#1855 when we try to work around that with a union.
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@ambv Done. |
python/typeshed#1527 has landed in mypy master, which is what we use in tests.
python/typeshed#1527 has landed in mypy master, which is what we use in tests.
This reflects the code in the cpython tree and makes the following
(valid) code type-check correctly: