chore(deps-dev): update mypy requirement from !=1.20.2,<1.21,>=1.0.0 to >=2.0.0,<2.4

[dependabot]

Updates the requirements on mypy to permit the latest version.

Changelog

Sourced from mypy's changelog.

Mypy Release Notes

Next Release

Packaging changes

• No longer provide mypyc-accelerated wheels for macOS x86_64 [mypyc-wheels #119](mypyc/mypy_mypyc-wheels#119)

Mypy 2.3

We've just uploaded mypy 2.3.0 to the Python Package Index (PyPI). Mypy is a static type checker for Python. This release includes new features, performance improvements and bug fixes. You can install it as follows:

python3 -m pip install -U mypy

You can read the full documentation for this release on Read the Docs.

The Upcoming Switch to the New Native Parser

We are planning to enable the new native parser (--native-parser) by default soon. We recommend that you test the native parser in your projects and report any issues in the mypy issue tracker.

Mypyc Free-threading Memory Safety

Free-threaded Python builds that don't have the GIL require additional synchronization primitives or lock-free algorithms to ensure memory safety when there are race conditions (for example, when a thread reads a list item while another thread writes the same list item concurrently). This release greatly improves memory safety of free threading.

List operations are now memory-safe on free threaded Python builds, even in the presence of race conditions. This has some performance cost. For list-heavy workloads, using librt.vecs.vec instead of list is often significantly faster, but note that vec is not (and likely won't be) fully memory safe, and the user is expected to avoid race conditions. The newly introduced librt.threading.Lock helps with this. Using variable-length tuples can also be more efficient than lists, since tuples are immutable and don't require expensive synchronization to ensure memory safety.

Instance attribute access is also (mostly) memory safe now on free-threaded builds in the presence of race conditions. We are planning to fix the remaining unsafe cases in a future release.

Full list of changes:

• Make attribute access memory safe on free-threaded builds (Jukka Lehtosalo, PR 21705)
• Fix unsafe borrowing of instance attributes with free-threading (Jukka Lehtosalo, PR 21688)
• Make list get/set item more memory safe on free-threaded builds (Jukka Lehtosalo, PR 21683)
• Don't borrow list items on free-threaded builds (Jukka Lehtosalo, PR 21679)
• Make multiple assignment from list memory-safe on free-threaded builds (Jukka Lehtosalo, PR 21684)

... (truncated)

Commits

• 8aabf84 Drop +dev from version
• 4d8ad2a Update changelog for 2.3 release (#21728)
• 2c21546 [mypyc] Update documentation of race conditions under free threading (#21726)
• a9f62a3 [mypyc] Make attribute access memory safe on free-threaded builds (#21705)
• 0faa413 Use PYODIDE environment variable for Emscripten cross-compilation detection...
• 3d75cdb [mypyc] Borrow final attributes more aggressively (#21702)
• 24c237d [mypyc] Improve documentation of Final (#21713)
• b5be217 [mypyc] Update free threading Python compatibility docs (#21711)
• cbcb51a Narrow for frozendict membership check (#21709)
• af2bc0f Sync typeshed (#21707)
• Additional commits viewable in compare view

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[jenstroeger]

@behnazh if we use a SQLite cache for mypy then as of v2.0.0 we get failures like this one (see this failing v2.3.0 run):

Check typing annotations.................................................Failed
- hook id: mypy
- exit code: 2

error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 2.3.0
Traceback (most recent call last):
  File "/path/to/python-package-template/.venv/lib/python3.14/site-packages/mypy/__main__.py", line 16, in console_entry
    main()
    ~~~~^^
  File "mypy/main.py", line 154, in main
  File "mypy/main.py", line 244, in run_build
    res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
  File "mypy/build.py", line 385, in build
  File "mypy/build.py", line 1908, in create_metastore
    mds: MetadataStore = SqliteMetadataStore(
  File "mypy/metastore.py", line 200, in __init__
  File "mypy/metastore.py", line 174, in connect_db
    db.execute("PRAGMA journal_mode=WAL")
sqlite3.OperationalError: database is locked

note: use --pdb to drop into pdb
Success: no issues found in 3 source files

This issue has been around since v2.1.0 (run) and v2.2.0 (run),¹² but it hasn’t been reported. It seems independent of the new parallel type-checking. I’m not sure what’s going on or whether I should open an issue with mypy — this one seems like an obvious problem that others should also run into?

Anyway, for the time being it seems like disabling the SQLite db (docs, commit 2805c1f, successful run) works; it’s ok to do so because we’re not using the cache anyway due to the incremental = false setting (code).

Footnotes

1. I think we missed the v2.0.0 run from 6. May which was followed by v2.1.0 on 13. May and our Dependabot interval just didn’t pick it up. Older runs aren’t available anymore, either. ↩

2. See also issue https://github.com/jenstroeger/python-package-template/pull/1152, which I think had a similar/same problem 🤔 ↩

[behnazh]

Anyway, for the time being it seems like disabling the SQLite db (docs, commit 2805c1f, successful run) works

I just tried make check-mypy on this branch, setting no_sqlite_cache to false and it passed:

python --version
Python 3.14.6

[jenstroeger]

I just tried make check-mypy on this branch, setting no_sqlite_cache to false and it passed:

@behnazh try this:

rm -fr .mypy_cache/
make check-mypy

after removing/commenting out # no_sqlite_cache = true (commit 2805c1f). Or try

make nuke

and start with a completely fresh setup, like it does in CI. I think I forgot to mention that this happens only with a first run when the SQLite db is created.

[behnazh]

rm -fr .mypy_cache/

Hm, it still passes.

(python-package-template) $ git diff
diff --git a/pyproject.toml b/pyproject.toml
index 87223ad..76d33d4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -145,7 +145,7 @@ disallow_incomplete_defs = true
 disallow_untyped_decorators = true
 # disable_error_code =
 # allow_redefinition =
-no_sqlite_cache = true
+no_sqlite_cache = false
 
 [[tool.mypy.overrides]]
 module = [
(python-package-template) $ rm -fr .mypy_cache/
(python-package-template) $ make check-mypy
pre-commit run mypy --all-files
Check typing annotations.................................................Passed

[jenstroeger]

@behnazh interesting because CI for Ubuntu (or are you on your Mac) and Python 3.14 fails (run) 🤔 Does a fresh clone fail when you remove the entire no_sqlite_cache line?

[behnazh]

@behnazh interesting because CI for Ubuntu (or are you on your Mac) and Python 3.14 fails (run) 🤔 Does a fresh clone fail when you remove the entire no_sqlite_cache line?

I'm testing it on a Mac and it passes on a fresh clone.

[jenstroeger]

CI on Mac with Python 3.14 passes too (run); Python 3.13 does not.

[jenstroeger]

Opened issue python/mypy#21769.