chore: update pre-commit hook mypy

[DimitriPapadopoulos]

updates:

• github.com/pre-commit/mirrors-mypy: v1.16.0 → v1.20.0 v1.18.2

TODO:

• Unit tests and/or doctests in docstrings
• Tests pass locally
• Docstrings and API docs for any new/modified user-facing classes and functions
• Changes documented in docs/release.rst
• Docs build locally
• GitHub Actions CI passes
• Test coverage to 100% (Codecov passes)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.89%. Comparing base (e46dfcf) to head (53c3e5e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##              main     #835      +/-   ##
===========================================
- Coverage   100.00%   98.89%   -1.11%     
===========================================
  Files           27       27              
  Lines          901      901              
===========================================
- Hits           901      891      -10     
- Misses           0       10      +10     

see 1 file with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[d-v-b]

why do we need a new type: ignore here? Is this improved type safety (if so, how?) or is this a regression in mypy

[DimitriPapadopoulos]

I think this is a regression, but I often have a hard time understanding Python typing. The error can be seen in https://results.pre-commit.ci/run/github/68207196/1775503887.A9wQYmi0SzyJZg-CuQfz6A:

tests/test_zarr3.py:48: error: Module has no attribute "codecs"

I understand MyPy believes that the zarr>=3.1.3 module does not have a codecs submodule. I don't see why:
https://github.com/zarr-developers/zarr-python/tree/de947648e6ab6e7079ddb4f33b6b56070c3e6657/src/zarr/codecs

[d-v-b]

if the only effect of this version bump is a new mypy bug to mitigate, then maybe we wait for 1.20.1 😅

[DimitriPapadopoulos]

Let me find which exact version introduces this issue.

[DimitriPapadopoulos]

Strange, I cannot reproduce this issue outside pre-commit, instead I get other similar and nonsensical error messages with MyPy ≥ 1.19.0:

$ uvx mypy@v1.18.2 tests
Success: no issues found in 39 source files
$ 
$ uvx mypy@v1.19.0 tests
tests/test_checksum32.py:19: error: Module has no attribute "util"  [attr-defined]
tests/test_checksum32.py:20: error: Module has no attribute "util"  [attr-defined]
Found 2 errors in 1 file (checked 39 source files)
$ 
$ uvx mypy@v1.20.0 tests
tests/test_checksum32.py:19: error: Module has no attribute "util"  [attr-defined]
tests/test_checksum32.py:20: error: Module has no attribute "util"  [attr-defined]
Found 2 errors in 1 file (checked 39 source files)
$ 

The module is importlib:

numcodecs/tests/test_checksum32.py

Lines 19 to 20 in 1fdde70

	has_google_crc32c = importlib.util.find_spec("google_crc32c") is not None
	has_legacy_crc32c = importlib.util.find_spec("crc32c") is not None

and of course importlib does have the util submodule.

I fail to understand why MyPy emits different errors within pre-commit and outside pre-commit.

[DimitriPapadopoulos]

Meanwhile, let's bump to 1.18.2.

[DimitriPapadopoulos]

It's easy to fix for MyPy ≥ 1.19.0:

-    import zarr.
+    import zarr.codecs

Not sure it makes sense, but it doesn't hurt.

I still fail to understand why MyPy emits different errors within pre-commit and outside pre-commit.