Update pre-commit hooks + mypy fixes

[dstansby]

Replaces #3109.

[dstansby]

@d-v-b any ideas what's going on with the typing error here? I can't wrap my head around why it's erroring. Perhaps we should just stick an # type: ignore comment on the failing line?

[DimitriPapadopoulos]

I wonder whether this would fix the mypy error:

-    if dtype_category == "variable-length-string":
-        zdtype = VariableLengthUTF8()
-    else:
-        zdtype = Int8()
+    if dtype_category == "variable-length-string":
+        zdtype = VariableLengthUTF8
+    else:
+        zdtype = Int8

[dstansby]

The issue with the dtype mypy error was the variable length string type is not actually a valid ZarrDtype. Since there are existing #type: ignore comments to acocunt for this, I added another one here.

[d-v-b]

@d-v-b any ideas what's going on with the typing error here? I can't wrap my head around why it's erroring. Perhaps we should just stick an # type: ignore comment on the failing line?

which specific typing error? a basic challenge with VariableLengthUTF8 is that it's conditionally defined: if numpy < 2 is installed, we define 1 version of the class (using the numpy object dtype) and if numpy > 2 is installed, we define a different version of the class (using np.dtypes.StringDType). That can be why mypy singles this type out as unknown

[dstansby]

This line here: https://github.com/zarr-developers/zarr-python/pull/3133/files#diff-da24b355349b53e4c8047034767d008e4c2ce9ea6c8933a3acd50d0828f00528R334 - if you remove the typing ignores, it gives an error.

[d-v-b]

This line here: https://github.com/zarr-developers/zarr-python/pull/3133/files#diff-da24b355349b53e4c8047034767d008e4c2ce9ea6c8933a3acd50d0828f00528R334 - if you remove the typing ignores, it gives an error.

yeah, mypy is confused there, so the type ignore is correct. This will get simpler in a few months when we drop numpy < 2.

[d-v-b]

thanks!

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.47%. Comparing base (2836883) to head (9cc7740).
⚠️ Report is 128 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3133   +/-   ##
=======================================
  Coverage   94.47%   94.47%           
=======================================
  Files          78       78           
  Lines        8578     8578           
=======================================
  Hits         8104     8104           
  Misses        474      474           

Files with missing lines	Coverage Δ
src/zarr/core/buffer/core.py	82.17% <100.00%> (ø)
src/zarr/core/dtype/npy/bytes.py	96.77% <100.00%> (ø)
src/zarr/core/dtype/npy/structured.py	96.47% <100.00%> (ø)
src/zarr/core/dtype/npy/time.py	95.20% <ø> (ø)
src/zarr/storage/_memory.py	93.06% <100.00%> (ø)
src/zarr/storage/_zip.py	97.05% <100.00%> (ø)

🚀 New features to boost your workflow:

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