Skip to content

Conversation

@renovate
Copy link
Contributor

@renovate renovate bot commented Feb 5, 2026

This PR contains the following updates:

Package Change Age Confidence
mypy (changelog) ==1.14.1==1.19.1 age confidence

Release Notes

python/mypy (mypy)

v1.19.1

Compare Source

  • Fix noncommutative joins with bounded TypeVars (Shantanu, PR 20345)
  • Respect output format for cached runs by serializing raw errors in cache metas (Ivan Levkivskyi, PR 20372)
  • Allow types.NoneType in match cases (A5rocks, PR 20383)
  • Fix mypyc generator regression with empty tuple (BobTheBuidler, PR 20371)
  • Fix crash involving Unpack-ed TypeVarTuple (Shantanu, PR 20323)
  • Fix crash on star import of redefinition (Ivan Levkivskyi, PR 20333)
  • Fix crash on typevar with forward ref used in other module (Ivan Levkivskyi, PR 20334)
  • Fail with an explicit error on PyPy (Ivan Levkivskyi, PR 20389)

v1.19.0

Compare Source

v1.18.2

Compare Source

  • Fix crash on recursive alias (Ivan Levkivskyi, PR 19845)
  • Add additional guidance for stubtest errors when runtime is object.__init__ (Stephen Morton, PR 19733)
  • Fix handling of None values in f-string expressions in mypyc (BobTheBuidler, PR 19846)

v1.18.1

Compare Source

We’ve just uploaded mypy 1.18.1 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.

Mypy Performance Improvements

Mypy 1.18.1 includes numerous performance improvements, resulting in about 40% speedup
compared to 1.17 when type checking mypy itself. In extreme cases, the improvement
can be 10x or higher. The list below is an overview of the various mypy optimizations.
Many mypyc improvements (discussed in a separate section below) also improve performance.

Type caching optimizations have a small risk of causing regressions. When
reporting issues with unexpected inferred types, please also check if
--disable-expression-cache will work around the issue, as it turns off some of
these optimizations.

  • Improve self check performance by 1.8% (Jukka Lehtosalo, PR 19768, 19769, 19770)
  • Optimize fixed-format deserialization (Ivan Levkivskyi, PR 19765)
  • Use macros to optimize fixed-format deserialization (Ivan Levkivskyi, PR 19757)
  • Two additional micro‑optimizations (Ivan Levkivskyi, PR 19627)
  • Another set of micro‑optimizations (Ivan Levkivskyi, PR 19633)
  • Cache common types (Ivan Levkivskyi, PR 19621)
  • Skip more method bodies in third‑party libraries for speed (Ivan Levkivskyi, PR 19586)
  • Simplify the representation of callable types (Ivan Levkivskyi, PR 19580)
  • Add cache for types of some expressions (Ivan Levkivskyi, PR 19505)
  • Use cache for dictionary expressions (Ivan Levkivskyi, PR 19536)
  • Use cache for binary operations (Ivan Levkivskyi, PR 19523)
  • Cache types of type objects (Ivan Levkivskyi, PR 19514)
  • Avoid duplicate work when checking boolean operations (Ivan Levkivskyi, PR 19515)
  • Optimize generic inference passes (Ivan Levkivskyi, PR 19501)
  • Speed up the default plugin (Jukka Lehtosalo, PRs 19385 and 19462)
  • Remove nested imports from the default plugin (Ivan Levkivskyi, PR 19388)
  • Micro‑optimize type expansion (Jukka Lehtosalo, PR 19461)
  • Micro‑optimize type indirection (Jukka Lehtosalo, PR 19460)
  • Micro‑optimize the plugin framework (Jukka Lehtosalo, PR 19464)
  • Avoid temporary set creation in subtype checking (Jukka Lehtosalo, PR 19463)
  • Subtype checking micro‑optimization (Jukka Lehtosalo, PR 19384)
  • Return early where possible in subtype check (Stanislav Terliakov, PR 19400)
  • Deduplicate some types before joining (Stanislav Terliakov, PR 19409)
  • Speed up type checking by caching argument inference context (Jukka Lehtosalo, PR 19323)
  • Optimize binding method self argument type and deprecation checks (Ivan Levkivskyi, PR 19556)
  • Keep trivial instance types/aliases during expansion (Ivan Levkivskyi, PR 19543)
Fixed‑Format Cache (Experimental)

Mypy now supports a new cache format used for faster incremental builds. It makes
incremental builds up to twice as fast. The feature is experimental and
currently only supported when using a compiled version of mypy. Use --fixed-format-cache
to enable the new format, or fixed_format_cache = True in a configuration file.

We plan to enable this by default in a future mypy release, and we'll eventually
deprecate and remove support for the original JSON-based format.

Unlike the JSON-based cache format, the new binary format is currently
not easy to parse and inspect by mypy users. We are planning to provide a tool to
convert fixed-format cache files to JSON, but details of the output JSON may be
different from the current JSON format. If you rely on being able to inspect
mypy cache files, we recommend creating a GitHub issue and explaining your use
case, so that we can more likely provide support for it. (Using
MypyFile.read(binary_data) to inspect cache data may be sufficient to support
some use cases.)

This feature was contributed by Ivan Levkivskyi (PR 19668, 19735, 19750, 19681, 19752, 19815).

Flexible Variable Definitions: Update

Mypy 1.16.0 introduced --allow-redefinition-new, which allows redefining variables
with different types, and inferring union types for variables from multiple assignments.
The feature is now documented in the --help output, but the feature is still experimental.

We are planning to enable this by default in mypy 2.0, and we will also deprecate the
older --allow-redefinition flag. Since the new behavior differs significantly from
the older flag, we encourage users of --allow-redefinition to experiment with
--allow-redefinition-new and create a GitHub issue if the new functionality doesn't
support some important use cases.

This feature was contributed by Jukka Lehtosalo.

Inferred Type for Bare ClassVar

A ClassVar without an explicit type annotation now causes the type of the variable
to be inferred from the initializer:

from typing import ClassVar

class Item:

### Type of 'next_id' is now 'int' (it was 'Any')
    next_id: ClassVar = 1

    ...

This feature was contributed by Ivan Levkivskyi (PR 19573).

Disjoint Base Classes (@​disjoint_base, PEP 800)

Mypy now understands disjoint bases (PEP 800): it recognizes the @disjoint_base
decorator, and rejects class definitions that combine mutually incompatible base classes,
and takes advantage of the fact that such classes cannot exist in reachability and
narrowing logic.

This class definition will now generate an error:

v1.17.1

Compare Source

  • Retain None as constraints bottom if no bottoms were provided (Stanislav Terliakov, PR 19485)
  • Fix "ignored exception in hasattr" in dmypy (Stanislav Terliakov, PR 19428)
  • Prevent a crash when InitVar is redefined with a method in a subclass (Stanislav Terliakov, PR 19453)

v1.17.0

Compare Source

v1.16.1

Compare Source

v1.16.0

Compare Source

v1.15.0

Compare Source


Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate bot requested a review from a team as a code owner February 5, 2026 18:47
@renovate
Copy link
Contributor Author

renovate bot commented Feb 5, 2026

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

  • any of the package files in this branch needs updating, or
  • the branch becomes conflicted, or
  • you click the rebase/retry checkbox if found above, or
  • you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: uv.lock
Command failed: uv lock --upgrade-package mypy
Using CPython 3.14.3 interpreter at: /opt/containerbase/tools/python/3.14.3/bin/python3
  × No solution found when resolving dependencies for split (markers:
  │ python_full_version == '3.8.*'):
  ╰─▶ Because the requested Python version (>=3.8) does not satisfy
      Python>=3.9 and mypy==1.19.1 depends on Python>=3.9, we can conclude
      that mypy==1.19.1 cannot be used.
      And because workos:dev depends on mypy==1.19.1 and your project requires
      workos:dev, we can conclude that your project's requirements are
      unsatisfiable.

      hint: While the active Python version is 3.14, the resolution failed for
      other Python versions supported by your project. Consider limiting your
      project's supported Python versions using `requires-python`.

      hint: The `requires-python` value (>=3.8) includes Python versions that
      are not supported by your dependencies (e.g., mypy==1.19.1 only supports
      >=3.9). Consider using a more restrictive `requires-python` value (like
      >=3.9).

@renovate renovate bot requested a review from mthadley February 5, 2026 18:48
@greptile-apps
Copy link
Contributor

greptile-apps bot commented Feb 5, 2026

Greptile Overview

Greptile Summary

This PR updates the type_check dependency group in pyproject.toml to use mypy==1.19.1 instead of mypy==1.14.1. The change is limited to the dependency pin used for static type checking and does not modify runtime dependencies or library code.

Confidence Score: 5/5

  • This PR is safe to merge with minimal risk.
  • The change is a straightforward dev-tool version bump isolated to the type_check dependency group and does not affect runtime code paths. The diff is small and self-contained.
  • No files require special attention

Important Files Changed

Filename Overview
pyproject.toml Bumps the development type-checking dependency group from mypy==1.14.1 to mypy==1.19.1; no other configuration changes.

Sequence Diagram

sequenceDiagram
    participant Dev as Developer
    participant UV as uv/pip
    participant PP as pyproject.toml
    participant Mypy as mypy

    Dev->>PP: Update type_check group (mypy==1.19.1)
    Dev->>UV: Install dev dependencies
    UV->>PP: Resolve type_check group
    UV-->>Mypy: Install mypy 1.19.1
    Dev->>Mypy: Run type checking
    Mypy-->>Dev: Type check results
Loading

Copy link
Contributor

@greptile-apps greptile-apps bot left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

1 file reviewed, no comments

Edit Code Review Agent Settings | Greptile

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Development

Successfully merging this pull request may close these issues.

0 participants