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.github/workflows/tests.yaml

run: python3 tests.py

- name: verify type hints

run: mypy datemath

run: mypy . --strict

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Running on tests is important too. This ensures expected usage is correctly typed. In fact, it found that parse was missing the int annotation on its first parameter.

Avasam

Avasam commented

datemath/__init__.py

@@ -1,9 +1,18 @@

from .helpers import parse, DateMathException

from __future__ import annotations

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@Avasam Avasam Aug 25, 2024 •

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This allows the use of | in Pyton < 3.10, and use symbols that won't be present at runtime, in annotations.

Avasam

Avasam commented

datemath/__init__.py

from typing_extensions import Unpack

from arrow import Arrow

from .helpers import ParseParams, parse as parse, DateMathException as DateMathException

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@Avasam Avasam Aug 25, 2024 •

edited

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as imports without renaming is a typing convention understood by type-checkers to mean that the symbol is purposefully / explicitly re-exported (the other option is to use __all__)

Avasam

Avasam commented

datemath/__init__.py

from .helpers import ParseParams, parse as parse, DateMathException as DateMathException

def dm(expr: str | int, **kwargs: Unpack[ParseParams]) -> Arrow:

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By using an unpacked TypedDict to annotate kwargs, you don't have to duplicate all your default keyword argument parameter's default values to have these functions fully typed.

Avasam

Avasam commented

raise DateMathException("Not a valid timeunit: {0}".format(c))

def parse(expression: str, now: Any = None, tz: str = 'UTC', type: Any = None, roundDown: bool = True) -> Arrow:

class ParseParams(TypedDict, total=False):

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@Avasam Avasam Aug 25, 2024 •

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See comment in datemath/__init__.py
total=False means all members are optional (since we use this to annotate optional kwargs)

Avasam

Avasam commented

if debug: print("parse() - Now, no dm: {0}".format(now))

if type:

return getattr(now, type)

return cast(Arrow, getattr(now, type))

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@Avasam Avasam Aug 25, 2024 •

edited

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In strict mode, mypy will whine about returning Any from a typed function.
This can either be cast or type-ignored to accept the "type unsafety".

Suggested change

return cast(Arrow, getattr(now, type))

return getattr(now, type)# type: ignore[no-any-return]

Avasam

Avasam commented

if debug: print("parse() - will now convert tz to {0}".format(tz))

now = now.to(tz)

expression = str(expression)

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Less runtime casting in some cases. But more importantly, this is now type-safe.

Avasam

Avasam commented

Comment on lines +189 to +190

now = now.floor(unit)# type: ignore[arg-type]

else:

now = now.ceil(unit)

now = now.ceil(unit)# type: ignore[arg-type]

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arrow types these only with the literal strings they accept. I figured you'd probably prefer keeping the types and checks simpler with a more general str, as any usage of roundDate would also have to comply to only using statically known literals.

Avasam

Avasam commented

tests-legacy.py

@@ -1,4 +1,4 @@

import unittest2asunittest

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@Avasam Avasam Aug 25, 2024

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unittest2 is untyped, but also no longer needed without Python 2 support.

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@nickmaccarthy nickmaccarthy Aug 27, 2024

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This file is going to get removed in the next release anyways since this package is only going to be python3 going forward

@Avasam Avasam force-pushed the complete-typing-with-strict-checking branch 2 times, most recently from 2fa344b to c90f0bc Compare

August 25, 2024 03:41

Avasam

Avasam commented

if type:

return getattr(rettime, type)

return cast(Arrow, getattr(rettime, type))

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@Avasam Avasam Aug 25, 2024 •

edited

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In strict mode, mypy will whine about returning Any from a typed function.
This can either be cast or type-ignored to accept the "type unsafety".

Suggested change

return cast(Arrow, getattr(rettime, type))

return getattr(rettime, type)# type: ignore[no-any-return]

@Avasam Avasam force-pushed the complete-typing-with-strict-checking branch from c90f0bc to 5d1bb8f Compare

August 25, 2024 03:49

@nickmaccarthy

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nickmaccarthy commented Aug 26, 2024

Thank you so much for your contribution @Avasam ! This is quite awesome!! I've been writing so much golang lately that I have taking the typing for granted and it seems folks really needed it for this module. I'll approve it and merge it. I'll get a release out soon. There are few other things I'd like to tidy up before the next one first related to the legacy python 2.7 support we had.

@Avasam


 Complete typing with strict type-checking

360cc11

@Avasam Avasam force-pushed the complete-typing-with-strict-checking branch from 5d1bb8f to 360cc11 Compare

August 26, 2024 21:46

Avasam

Avasam commented

Aug 26, 2024