Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Update mypy to 1.14.1 #8147

Open
wants to merge 1 commit into
base: rewrite
Choose a base branch
from
Open

Update mypy to 1.14.1 #8147

wants to merge 1 commit into from

Conversation

pyup-bot
Copy link
Collaborator

This PR updates mypy from 1.7.1 to 1.14.1.

Changelog

1.14

We’ve just uploaded mypy 1.14 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)).
Mypy is a static type checker for Python. This release includes new features 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](http://mypy.readthedocs.io).

Change to Enum Membership Semantics

As per the updated [typing specification for enums](https://typing.readthedocs.io/en/latest/spec/enums.html#defining-members),
enum members must be left unannotated.

python
class Pet(Enum):
 CAT = 1   Member attribute
 DOG = 2   Member attribute

  New error: Enum members must be left unannotated
 WOLF: int = 3

 species: str   Considered a non-member attribute


In particular, the specification change can result in issues in type stubs (`.pyi` files), since
historically it was common to leave the value absent:

python
In a type stub (.pyi file)

class Pet(Enum):
  Change in semantics: previously considered members,
  now non-member attributes
 CAT: int
 DOG: int

  Mypy will now issue a warning if it detects this
  situation in type stubs:
  > Detected enum "Pet" in a type stub with zero
  > members. There is a chance this is due to a recent
  > change in the semantics of enum membership. If so,
  > use `member = value` to mark an enum member,
  > instead of `member: type`

class Pet(Enum):
  As per the specification, you should now do one of
  the following:
 DOG = 1   Member attribute with value 1 and known type
 WOLF = cast(int, ...)   Member attribute with unknown
                         value but known type
 LION = ...   Member attribute with unknown value and
               unknown type


Contributed by Terence Honles (PR [17207](https://github.com/python/mypy/pull/17207)) and
Shantanu Jain (PR [18068](https://github.com/python/mypy/pull/18068)).

Support for deprecated Decorator (PEP 702)

Mypy can now issue errors or notes when code imports a deprecated feature
explicitly with a `from mod import depr` statement, or uses a deprecated feature
imported otherwise or defined locally. Features are considered deprecated when
decorated with `warnings.deprecated`, as specified in [PEP 702](https://peps.python.org/pep-0702).

You can enable the error code via `--enable-error-code=deprecated` on the mypy
command line or `enable_error_code = deprecated` in the mypy config file.
Use the command line flag `--report-deprecated-as-note` or config file option
`report_deprecated_as_note=True` to turn all such errors into notes.

Deprecation errors will be enabled by default in a future mypy version.

This feature was contributed by Christoph Tyralla.

List of changes:

* Add basic support for PEP 702 (`deprecated`) (Christoph Tyralla, PR [17476](https://github.com/python/mypy/pull/17476))
* Support descriptors with `deprecated` (Christoph Tyralla, PR [18090](https://github.com/python/mypy/pull/18090))
* Make "deprecated" note an error, disabled by default (Valentin Stanciu, PR [18192](https://github.com/python/mypy/pull/18192))
* Consider all possible type positions with `deprecated` (Christoph Tyralla, PR [17926](https://github.com/python/mypy/pull/17926))
* Improve the handling of explicit type annotations in assignment statements with `deprecated` (Christoph Tyralla, PR [17899](https://github.com/python/mypy/pull/17899))

Optionally Analyzing Untyped Modules

Mypy normally doesn't analyze imports from third-party modules (installed using pip, for example)
if there are no stubs or a py.typed marker file. To force mypy to analyze these imports, you
can now use the `--follow-untyped-imports` flag or set the `follow_untyped_imports`
config file option to True. This can be set either in the global section of your mypy config
file, or individually on a per-module basis.

This feature was contributed by Jannick Kremer.

List of changes:

* Implement flag to allow type checking of untyped modules (Jannick Kremer, PR [17712](https://github.com/python/mypy/pull/17712))
* Warn about `--follow-untyped-imports` (Shantanu, PR [18249](https://github.com/python/mypy/pull/18249))

Support New Style Type Variable Defaults (PEP 696)

Mypy now supports type variable defaults using the new syntax described in PEP 696, which
was introduced in Python 3.13. Example:

python
dataclass
class Box[T = int]:   Set default for "T"
 value: T | None = None

reveal_type(Box())                       type is Box[int], since it's the default
reveal_type(Box(value="Hello World!"))   type is Box[str]


This feature was contributed by Marc Mueller (PR [17985](https://github.com/python/mypy/pull/17985)).

Improved For Loop Index Variable Type Narrowing

Mypy now preserves the literal type of for loop index variables, to support `TypedDict`
lookups. Example:

python
from typing import TypedDict

class X(TypedDict):
 hourly: int
 daily: int

def func(x: X) -> int:
 s = 0
 for var in ("hourly", "daily"):
      "Union[Literal['hourly']?, Literal['daily']?]"
     reveal_type(var)

      x[var] no longer triggers a literal-required error
     s += x[var]
 return s


This was contributed by Marc Mueller (PR [18014](https://github.com/python/mypy/pull/18014)).

Mypyc Improvements

* Document optimized bytes operations and additional str operations (Jukka Lehtosalo, PR [18242](https://github.com/python/mypy/pull/18242))
* Add primitives and specialization for `ord()` (Jukka Lehtosalo, PR [18240](https://github.com/python/mypy/pull/18240))
* Optimize `str.encode` with specializations for common used encodings (Valentin Stanciu, PR [18232](https://github.com/python/mypy/pull/18232))
* Fix fall back to generic operation for staticmethod and classmethod (Advait Dixit, PR [18228](https://github.com/python/mypy/pull/18228))
* Support unicode surrogates in string literals (Jukka Lehtosalo, PR [18209](https://github.com/python/mypy/pull/18209))
* Fix index variable in for loop with `builtins.enumerate` (Advait Dixit, PR [18202](https://github.com/python/mypy/pull/18202))
* Fix check for enum classes (Advait Dixit, PR [18178](https://github.com/python/mypy/pull/18178))
* Fix loading type from imported modules (Advait Dixit, PR [18158](https://github.com/python/mypy/pull/18158))
* Fix initializers of final attributes in class body (Jared Hance, PR [18031](https://github.com/python/mypy/pull/18031))
* Fix name generation for modules with similar full names (aatle, PR [18001](https://github.com/python/mypy/pull/18001))
* Fix relative imports in `__init__.py` (Shantanu, PR [17979](https://github.com/python/mypy/pull/17979))
* Optimize dunder methods (jairov4, PR [17934](https://github.com/python/mypy/pull/17934))
* Replace deprecated `_PyDict_GetItemStringWithError` (Marc Mueller, PR [17930](https://github.com/python/mypy/pull/17930))
* Fix wheel build for cp313-win (Marc Mueller, PR [17941](https://github.com/python/mypy/pull/17941))
* Use public PyGen_GetCode instead of vendored implementation (Marc Mueller, PR [17931](https://github.com/python/mypy/pull/17931))
* Optimize calls to final classes (jairov4, PR [17886](https://github.com/python/mypy/pull/17886))
* Support ellipsis (`...`) expressions in class bodies (Newbyte, PR [17923](https://github.com/python/mypy/pull/17923))
* Sync `pythoncapi_compat.h` (Marc Mueller, PR [17929](https://github.com/python/mypy/pull/17929))
* Add `runtests.py mypyc-fast` for running fast mypyc tests (Jukka Lehtosalo, PR [17906](https://github.com/python/mypy/pull/17906))

Stubgen Improvements

* Do not include mypy generated symbols (Ali Hamdan, PR [18137](https://github.com/python/mypy/pull/18137))
* Fix `FunctionContext.fullname` for nested classes (Chad Dombrova, PR [17963](https://github.com/python/mypy/pull/17963))
* Add flagfile support (Ruslan Sayfutdinov, PR [18061](https://github.com/python/mypy/pull/18061))
* Add support for PEP 695 and PEP 696 syntax (Ali Hamdan, PR [18054](https://github.com/python/mypy/pull/18054))

Stubtest Improvements

* Allow the use of `--show-traceback` and `--pdb` with stubtest (Stephen Morton, PR [18037](https://github.com/python/mypy/pull/18037))
* Verify `__all__` exists in stub (Sebastian Rittau, PR [18005](https://github.com/python/mypy/pull/18005))
* Stop telling people to use double underscores (Jelle Zijlstra, PR [17897](https://github.com/python/mypy/pull/17897))

Documentation Updates

* Update config file documentation (sobolevn, PR [18103](https://github.com/python/mypy/pull/18103))
* Improve contributor documentation for Windows (ag-tafe, PR [18097](https://github.com/python/mypy/pull/18097))
* Correct note about `--disallow-any-generics` flag in documentation (Abel Sen, PR [18055](https://github.com/python/mypy/pull/18055))
* Further caution against `--follow-imports=skip` (Shantanu, PR [18048](https://github.com/python/mypy/pull/18048))
* Fix the edit page buttton link in documentation (Kanishk Pachauri, PR [17933](https://github.com/python/mypy/pull/17933))

Other Notables Fixes and Improvements

* Show `Protocol` `__call__` for arguments with incompatible types (MechanicalConstruct, PR [18214](https://github.com/python/mypy/pull/18214))
* Make join and meet symmetric with `strict_optional` (MechanicalConstruct, PR [18227](https://github.com/python/mypy/pull/18227))
* Preserve block unreachablility when checking function definitions with constrained TypeVars (Brian Schubert, PR [18217](https://github.com/python/mypy/pull/18217))
* Do not include non-init fields in the synthesized `__replace__` method for dataclasses (Victorien, PR [18221](https://github.com/python/mypy/pull/18221))
* Disallow `TypeVar` constraints parameterized by type variables (Brian Schubert, PR [18186](https://github.com/python/mypy/pull/18186))
* Always complain about invalid varargs and varkwargs (Shantanu, PR [18207](https://github.com/python/mypy/pull/18207))
* Set default strict_optional state to True (Shantanu, PR [18198](https://github.com/python/mypy/pull/18198))
* Preserve type variable default None in type alias (Sukhorosov Aleksey, PR [18197](https://github.com/python/mypy/pull/18197))
* Add checks for invalid usage of continue/break/return in `except*` block (coldwolverine, PR [18132](https://github.com/python/mypy/pull/18132))
* Do not consider bare TypeVar not overlapping with None for reachability analysis (Stanislav Terliakov, PR [18138](https://github.com/python/mypy/pull/18138))
* Special case `types.DynamicClassAttribute` as property-like (Stephen Morton, PR [18150](https://github.com/python/mypy/pull/18150))
* Disallow bare `ParamSpec` in type aliases (Brian Schubert, PR [18174](https://github.com/python/mypy/pull/18174))
* Move long_description metadata to pyproject.toml (Marc Mueller, PR [18172](https://github.com/python/mypy/pull/18172))
* Support `==`-based narrowing of Optional (Christoph Tyralla, PR [18163](https://github.com/python/mypy/pull/18163))
* Allow TypedDict assignment of Required item to NotRequired ReadOnly item (Brian Schubert, PR [18164](https://github.com/python/mypy/pull/18164))
* Allow nesting of Annotated with TypedDict special forms inside TypedDicts (Brian Schubert, PR [18165](https://github.com/python/mypy/pull/18165))
* Infer generic type arguments for slice expressions (Brian Schubert, PR [18160](https://github.com/python/mypy/pull/18160))
* Fix checking of match sequence pattern against bounded type variables (Brian Schubert, PR [18091](https://github.com/python/mypy/pull/18091))
* Fix incorrect truthyness for Enum types and literals (David Salvisberg, PR [17337](https://github.com/python/mypy/pull/17337))
* Move static project metadata to pyproject.toml (Marc Mueller, PR [18146](https://github.com/python/mypy/pull/18146))
* Fallback to stdlib json if integer exceeds 64-bit range (q0w, PR [18148](https://github.com/python/mypy/pull/18148))
* Fix 'or' pattern structural matching exhaustiveness (yihong, PR [18119](https://github.com/python/mypy/pull/18119))
* Fix type inference of positional parameter in class pattern involving builtin subtype (Brian Schubert, PR [18141](https://github.com/python/mypy/pull/18141))
* Fix `[override]` error with no line number when argument node has no line number (Brian Schubert, PR [18122](https://github.com/python/mypy/pull/18122))
* Fix some dmypy crashes (Ivan Levkivskyi, PR [18098](https://github.com/python/mypy/pull/18098))
* Fix subtyping between instance type and overloaded (Shantanu, PR [18102](https://github.com/python/mypy/pull/18102))
* Clean up new_semantic_analyzer config (Shantanu, PR [18071](https://github.com/python/mypy/pull/18071))
* Issue warning for enum with no members in stub (Shantanu, PR [18068](https://github.com/python/mypy/pull/18068))
* Fix enum attributes are not members (Terence Honles, PR [17207](https://github.com/python/mypy/pull/17207))
* Fix crash when checking slice expression with step 0 in tuple index (Brian Schubert, PR [18063](https://github.com/python/mypy/pull/18063))
* Allow union-with-callable attributes to be overridden by methods (Brian Schubert, PR [18018](https://github.com/python/mypy/pull/18018))
* Emit `[mutable-override]` for covariant override of attribute with method (Brian Schubert, PR [18058](https://github.com/python/mypy/pull/18058))
* Support ParamSpec mapping with `functools.partial` (Stanislav Terliakov, PR [17355](https://github.com/python/mypy/pull/17355))
* Fix approved stub ignore, remove normpath (Shantanu, PR [18045](https://github.com/python/mypy/pull/18045))
* Make `disallow-any-unimported` flag invertible (Séamus Ó Ceanainn, PR [18030](https://github.com/python/mypy/pull/18030))
* Filter to possible package paths before trying to resolve a module (falsedrow, PR [18038](https://github.com/python/mypy/pull/18038))
* Fix overlap check for ParamSpec types (Jukka Lehtosalo, PR [18040](https://github.com/python/mypy/pull/18040))
* Do not prioritize ParamSpec signatures during overload resolution (Stanislav Terliakov, PR [18033](https://github.com/python/mypy/pull/18033))
* Fix ternary union for literals (Ivan Levkivskyi, PR [18023](https://github.com/python/mypy/pull/18023))
* Fix compatibility checks for conditional function definitions using decorators (Brian Schubert, PR [18020](https://github.com/python/mypy/pull/18020))
* TypeGuard should be bool not Any when matching TypeVar (Evgeniy Slobodkin, PR [17145](https://github.com/python/mypy/pull/17145))
* Fix convert-cache tool (Shantanu, PR [17974](https://github.com/python/mypy/pull/17974))
* Fix generator comprehension with mypyc (Shantanu, PR [17969](https://github.com/python/mypy/pull/17969))
* Fix crash issue when using shadowfile with pretty (Max Chang, PR [17894](https://github.com/python/mypy/pull/17894))
* Fix multiple nested classes with new generics syntax (Max Chang, PR [17820](https://github.com/python/mypy/pull/17820))
* Better error for `mypy -p package` without py.typed (Joe Gordon, PR [17908](https://github.com/python/mypy/pull/17908))
* Emit error for `raise NotImplemented` (Brian Schubert, PR [17890](https://github.com/python/mypy/pull/17890))
* Add `is_lvalue` attribute to AttributeContext (Brian Schubert, PR [17881](https://github.com/python/mypy/pull/17881))

Acknowledgements

Thanks to all mypy contributors who contributed to this release:

- aatle
- Abel Sen
- Advait Dixit
- ag-tafe
- Alex Waygood
- Ali Hamdan
- Brian Schubert
- Carlton Gibson
- Chad Dombrova
- Chelsea Durazo
- chiri
- Christoph Tyralla
- coldwolverine
- David Salvisberg
- Ekin Dursun
- Evgeniy Slobodkin
- falsedrow
- Gaurav Giri
- Ihor
- Ivan Levkivskyi
- jairov4
- Jannick Kremer
- Jared Hance
- Jelle Zijlstra
- jianghuyiyuan
- Joe Gordon
- John Doknjas
- Jukka Lehtosalo
- Kanishk Pachauri
- Marc Mueller
- Max Chang
- MechanicalConstruct
- Newbyte
- q0w
- Ruslan Sayfutdinov
- Sebastian Rittau
- Shantanu
- sobolevn
- Stanislav Terliakov
- Stephen Morton
- Sukhorosov Aleksey
- Séamus Ó Ceanainn
- Terence Honles
- Valentin Stanciu
- vasiliy
- Victorien
- yihong

I’d also like to thank my employer, Dropbox, for supporting mypy development.

1.13

for improved performance. You can ensure the presence of `orjson` using the `faster-cache` extra:

 python3 -m pip install -U mypy[faster-cache]

Mypy may depend on `orjson` by default in the future.

These improvements were contributed by Shantanu.

List of changes:
* Significantly speed up file handling error paths (Shantanu, PR [17920](https://github.com/python/mypy/pull/17920))
* Use fast path in modulefinder more often (Shantanu, PR [17950](https://github.com/python/mypy/pull/17950))
* Let mypyc optimise os.path.join (Shantanu, PR [17949](https://github.com/python/mypy/pull/17949))
* Make is_sub_path faster (Shantanu, PR [17962](https://github.com/python/mypy/pull/17962))
* Speed up stubs suggestions (Shantanu, PR [17965](https://github.com/python/mypy/pull/17965))
* Use sha1 for hashing (Shantanu, PR [17953](https://github.com/python/mypy/pull/17953))
* Use orjson instead of json, when available (Shantanu, PR [17955](https://github.com/python/mypy/pull/17955))
* Add faster-cache extra, test in CI (Shantanu, PR [17978](https://github.com/python/mypy/pull/17978))

Acknowledgements
Thanks to all mypy contributors who contributed to this release:

- Shantanu Jain
- Jukka Lehtosalo

1.12.1

* Fix crash when showing partially analyzed type in error message (Ivan Levkivskyi, PR [17961](https://github.com/python/mypy/pull/17961))
* Fix iteration over union (when self type is involved) (Shantanu, PR [17976](https://github.com/python/mypy/pull/17976))
* Fix type object with type var default in union context (Jukka Lehtosalo, PR [17991](https://github.com/python/mypy/pull/17991))
* Revert change to `os.path` stubs affecting use of `os.PathLike[Any]` (Shantanu, PR [17995](https://github.com/python/mypy/pull/17995))

Acknowledgements
Thanks to all mypy contributors who contributed to this release:

- Ali Hamdan
- Anders Kaseorg
- Bénédikt Tran
- Brian Schubert
- bzoracler
- Chelsea Durazo
- Danny Yang
- Edgar Ramírez Mondragón
- Eric Mark Martin
- InSync
- Ivan Levkivskyi
- Jordandev678
- Katrina Connors
- Kirill Podoprigora
- Marc Mueller
- Max Muoto
- Max Murin
- Michael Carlstrom
- Michael I Chen
- Pradyun Gedam
- quinn-sasha
- Raphael Krupinski
- Sebastian Rittau
- Shantanu
- sobolevn
- Soubhik Kumar Mitra
- Stanislav Terliakov
- wyattscarpenter

I’d also like to thank my employer, Dropbox, for supporting mypy development.

1.12

We’ve just uploaded mypy 1.12 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).

Support Python 3.12 Syntax for Generics (PEP 695)

Support for the new type parameter syntax introduced in Python 3.12 is now enabled by default,
documented, and no longer experimental. It was available through a feature flag in
mypy 1.11 as an experimental feature.

This example demonstrates the new syntax:

python
Generic function
def f[T](x: T) -> T: ...

reveal_type(f(1))   Revealed type is 'int'

Generic class
class C[T]:
 def __init__(self, x: T) -> None:
    self.x = x

c = C('a')
reveal_type(c.x)   Revealed type is 'str'

Type alias
type A[T] = C[list[T]]


For more information, refer to the [documentation](https://mypy.readthedocs.io/en/latest/generics.html).

These improvements are included:

* Document Python 3.12 type parameter syntax (Jukka Lehtosalo, PR [17816](https://github.com/python/mypy/pull/17816))
* Further documentation updates (Jukka Lehtosalo, PR [17826](https://github.com/python/mypy/pull/17826))
* Allow Self return types with contravariance (Jukka Lehtosalo, PR [17786](https://github.com/python/mypy/pull/17786))
* Enable new type parameter syntax by default (Jukka Lehtosalo, PR [17798](https://github.com/python/mypy/pull/17798))
* Generate error if new-style type alias used as base class (Jukka Lehtosalo, PR [17789](https://github.com/python/mypy/pull/17789))
* Inherit variance if base class has explicit variance (Jukka Lehtosalo, PR [17787](https://github.com/python/mypy/pull/17787))
* Fix crash on invalid type var reference (Jukka Lehtosalo, PR [17788](https://github.com/python/mypy/pull/17788))
* Fix covariance of frozen dataclasses (Jukka Lehtosalo, PR [17783](https://github.com/python/mypy/pull/17783))
* Allow covariance with attribute that has "`_`" name prefix (Jukka Lehtosalo, PR [17782](https://github.com/python/mypy/pull/17782))
* Support `Annotated[...]` in new-style type aliases (Jukka Lehtosalo, PR [17777](https://github.com/python/mypy/pull/17777))
* Fix nested generic classes (Jukka Lehtosalo, PR [17776](https://github.com/python/mypy/pull/17776))
* Add detection and error reporting for the use of incorrect expressions within the scope of a type parameter and a type alias (Kirill Podoprigora, PR [17560](https://github.com/python/mypy/pull/17560))

Basic Support for Python 3.13

This release adds partial support for Python 3.13 features and compiled binaries for
Python 3.13. Mypyc now also supports Python 3.13.

In particular, these features are supported:
* Various new stdlib features and changes (through typeshed stub improvements)
* `typing.ReadOnly` (see below for more)
* `typing.TypeIs` (added in mypy 1.10, [PEP 742](https://peps.python.org/pep-0742/))
* Type parameter defaults when using the legacy syntax ([PEP 696](https://peps.python.org/pep-0696/))

These features are not supported yet:
* `warnings.deprecated` ([PEP 702](https://peps.python.org/pep-0702/))
* Type parameter defaults when using Python 3.12 type parameter syntax

Mypyc Support for Python 3.13

Mypyc now supports Python 3.13. This was contributed by Marc Mueller, with additional
fixes by Jukka Lehtosalo. Free threaded Python 3.13 builds are not supported yet.

List of changes:

* Add additional includes for Python 3.13 (Marc Mueller, PR [17506](https://github.com/python/mypy/pull/17506))
* Add another include for Python 3.13 (Marc Mueller, PR [17509](https://github.com/python/mypy/pull/17509))
* Fix ManagedDict functions for Python 3.13 (Marc Mueller, PR [17507](https://github.com/python/mypy/pull/17507))
* Update mypyc test output for Python 3.13 (Marc Mueller, PR [17508](https://github.com/python/mypy/pull/17508))
* Fix `PyUnicode` functions for Python 3.13 (Marc Mueller, PR [17504](https://github.com/python/mypy/pull/17504))
* Fix `_PyObject_LookupAttrId` for Python 3.13 (Marc Mueller, PR [17505](https://github.com/python/mypy/pull/17505))
* Fix `_PyList_Extend` for Python 3.13 (Marc Mueller, PR [17503](https://github.com/python/mypy/pull/17503))
* Fix `gen_is_coroutine` for Python 3.13 (Marc Mueller, PR [17501](https://github.com/python/mypy/pull/17501))
* Fix `_PyObject_FastCall` for Python 3.13 (Marc Mueller, PR [17502](https://github.com/python/mypy/pull/17502))
* Avoid uses of `_PyObject_CallMethodOneArg` on 3.13 (Jukka Lehtosalo, PR [17526](https://github.com/python/mypy/pull/17526))
* Don't rely on `_PyType_CalculateMetaclass` on 3.13 (Jukka Lehtosalo, PR [17525](https://github.com/python/mypy/pull/17525))
* Don't use `_PyUnicode_FastCopyCharacters` on 3.13 (Jukka Lehtosalo, PR [17524](https://github.com/python/mypy/pull/17524))
* Don't use `_PyUnicode_EQ` on 3.13, as it's no longer exported (Jukka Lehtosalo, PR [17523](https://github.com/python/mypy/pull/17523))

Inferring Unions for Conditional Expressions

Mypy now always tries to infer a union type for a conditional expression if left and right
operand types are different. This results in more precise inferred types and lets mypy detect
more issues. Example:

python
s = "foo" if cond() else 1
Type of "s" is now "str | int" (it used to be "object")


Notably, if one of the operands has type `Any`, the type of a conditional expression is
now `<type> | Any`. Previously the inferred type was just `Any`. The new type essentially
indicates that the value can be of type `<type>`, and potentially of some (unknown) type.
Most operations performed on the result must also be valid for `<type>`.
Example where this is relevant:

python
from typing import Any

def func(a: Any, b: bool) -> None:
 x = a if b else None
  Type of x is "Any | None"
 print(x.y)   Error: None has no attribute "y"


This feature was contributed by Ivan Levkivskyi (PR [17427](https://github.com/python/mypy/pull/17427)).

ReadOnly Support for TypedDict (PEP 705)

You can now use `typing.ReadOnly` to specity TypedDict items as
read-only ([PEP 705](https://peps.python.org/pep-0705/)):

python
from typing import TypedDict

Or "from typing ..." on Python 3.13
from typing_extensions import ReadOnly

class TD(TypedDict):
 a: int
 b: ReadOnly[int]

d: TD = {"a": 1, "b": 2}
d["a"] = 3   OK
d["b"] = 5   Error: "b" is ReadOnly


This feature was contributed by Nikita Sobolev (PR [17644](https://github.com/python/mypy/pull/17644)).

Python 3.8 End of Life Approaching

We are planning to drop support for Python 3.8 in the next mypy feature release or the
one after that. Python 3.8 reaches end of life in October 2024.

Planned Changes to Defaults

We are planning to enable `--local-partial-types` by default in mypy 2.0. This will
often require at least minor code changes. This option is implicitly enabled by mypy
daemon, so this makes the behavior of daemon and non-daemon modes consistent.

We recommend that mypy users start using local partial types soon (or to explicitly disable
them) to prepare for the change.

This can also be configured in a mypy configuration file:


local_partial_types = True


For more information, refer to the
[documentation](https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-local-partial-types).

Documentation Updates

Mypy documentation now uses modern syntax variants and imports in many examples. Some
examples no longer work on Python 3.8, which is the earliest Python version that mypy supports.

Notably, `Iterable` and other protocols/ABCs are imported from `collections.abc` instead of
`typing`:
python
from collections.abc import Iterable, Callable


Examples also avoid the upper-case aliases to built-in types: `list[str]` is used instead
of `List[str]`. The `X | Y` union type syntax introduced in Python 3.10 is also now prevalent.

List of documentation updates:

* Document `--output=json` CLI option (Edgar Ramírez Mondragón, PR [17611](https://github.com/python/mypy/pull/17611))
* Update various references to deprecated type aliases in docs (Jukka Lehtosalo, PR [17829](https://github.com/python/mypy/pull/17829))
* Make "X | Y" union syntax more prominent in documentation (Jukka Lehtosalo, PR [17835](https://github.com/python/mypy/pull/17835))
* Discuss upper bounds before self types in documentation (Jukka Lehtosalo, PR [17827](https://github.com/python/mypy/pull/17827))
* Make changelog visible in mypy documentation (quinn-sasha, PR [17742](https://github.com/python/mypy/pull/17742))
* List all incomplete features in `--enable-incomplete-feature` docs (sobolevn, PR [17633](https://github.com/python/mypy/pull/17633))
* Remove the explicit setting of a pygments theme (Pradyun Gedam, PR [17571](https://github.com/python/mypy/pull/17571))
* Document ReadOnly with TypedDict (Jukka Lehtosalo, PR [17905](https://github.com/python/mypy/pull/17905))
* Document TypeIs (Chelsea Durazo, PR [17821](https://github.com/python/mypy/pull/17821))

Experimental Inline TypedDict Syntax

Mypy now supports a non-standard, experimental syntax for defining anonymous TypedDicts.
Example:

python
def func(n: str, y: int) -> {"name": str, "year": int}:
 return {"name": n, "year": y}


The feature is disabled by default. Use `--enable-incomplete-feature=InlineTypedDict` to
enable it. *We might remove this feature in a future release.*

This feature was contributed by Ivan Levkivskyi (PR [17457](https://github.com/python/mypy/pull/17457)).

Stubgen Improvements

* Fix crash on literal class-level keywords (sobolevn, PR [17663](https://github.com/python/mypy/pull/17663))
* Stubgen add `--version` (sobolevn, PR [17662](https://github.com/python/mypy/pull/17662))
* Fix `stubgen --no-analysis/--parse-only` docs (sobolevn, PR [17632](https://github.com/python/mypy/pull/17632))
* Include keyword only args when generating signatures in stubgenc (Eric Mark Martin, PR [17448](https://github.com/python/mypy/pull/17448))
* Add support for detecting `Literal` types when extracting types from docstrings (Michael Carlstrom, PR [17441](https://github.com/python/mypy/pull/17441))
* Use `Generator` type var defaults (Sebastian Rittau, PR [17670](https://github.com/python/mypy/pull/17670))

Stubtest Improvements
* Add support for `cached_property` (Ali Hamdan, PR [17626](https://github.com/python/mypy/pull/17626))
* Add `enable_incomplete_feature` validation to `stubtest` (sobolevn, PR [17635](https://github.com/python/mypy/pull/17635))
* Fix error code handling in `stubtest` with `--mypy-config-file` (sobolevn, PR [17629](https://github.com/python/mypy/pull/17629))

Other Notables Fixes and Improvements

* Report error if using unsupported type parameter defaults (Jukka Lehtosalo, PR [17876](https://github.com/python/mypy/pull/17876))
* Fix re-processing cross-reference in mypy daemon when node kind changes (Ivan Levkivskyi, PR [17883](https://github.com/python/mypy/pull/17883))
* Don't use equality to narrow when value is IntEnum/StrEnum (Jukka Lehtosalo, PR [17866](https://github.com/python/mypy/pull/17866))
* Don't consider None vs IntEnum comparison ambiguous (Jukka Lehtosalo, PR [17877](https://github.com/python/mypy/pull/17877))
* Fix narrowing of IntEnum and StrEnum types (Jukka Lehtosalo, PR [17874](https://github.com/python/mypy/pull/17874))
* Filter overload items based on self type during type inference (Jukka Lehtosalo, PR [17873](https://github.com/python/mypy/pull/17873))
* Enable negative narrowing of union TypeVar upper bounds (Brian Schubert, PR [17850](https://github.com/python/mypy/pull/17850))
* Fix issue with member expression formatting (Brian Schubert, PR [17848](https://github.com/python/mypy/pull/17848))
* Avoid type size explosion when expanding types (Jukka Lehtosalo, PR [17842](https://github.com/python/mypy/pull/17842))
* Fix negative narrowing of tuples in match statement (Brian Schubert, PR [17817](https://github.com/python/mypy/pull/17817))
* Narrow falsey str/bytes/int to literal type (Brian Schubert, PR [17818](https://github.com/python/mypy/pull/17818))
* Test against latest Python 3.13, make testing 3.14 easy (Shantanu, PR [17812](https://github.com/python/mypy/pull/17812))
* Reject ParamSpec-typed callables calls with insufficient arguments (Stanislav Terliakov, PR [17323](https://github.com/python/mypy/pull/17323))
* Fix crash when passing too many type arguments to generic base class accepting single ParamSpec (Brian Schubert, PR [17770](https://github.com/python/mypy/pull/17770))
* Fix TypeVar upper bounds sometimes not being displayed in pretty callables (Brian Schubert, PR [17802](https://github.com/python/mypy/pull/17802))
* Added error code for overlapping function signatures (Katrina Connors, PR [17597](https://github.com/python/mypy/pull/17597))
* Check for `truthy-bool` in `not ...` unary expressions (sobolevn, PR [17773](https://github.com/python/mypy/pull/17773))
* Add missing lines-covered and lines-valid attributes (Soubhik Kumar Mitra, PR [17738](https://github.com/python/mypy/pull/17738))
* Fix another crash scenario with recursive tuple types (Ivan Levkivskyi, PR [17708](https://github.com/python/mypy/pull/17708))
* Resolve TypeVar upper bounds in `functools.partial` (Shantanu, PR [17660](https://github.com/python/mypy/pull/17660))
* Always reset binder when checking deferred nodes (Ivan Levkivskyi, PR [17643](https://github.com/python/mypy/pull/17643))
* Fix crash on a callable attribute with single unpack (Ivan Levkivskyi, PR [17641](https://github.com/python/mypy/pull/17641))
* Fix mismatched signature between checker plugin API and implementation (bzoracler, PR [17343](https://github.com/python/mypy/pull/17343))
* Indexing a type also produces a GenericAlias (Shantanu, PR [17546](https://github.com/python/mypy/pull/17546))
* Fix crash on self-type in callable protocol (Ivan Levkivskyi, PR [17499](https://github.com/python/mypy/pull/17499))
* Fix crash on NamedTuple with method and error in function (Ivan Levkivskyi, PR [17498](https://github.com/python/mypy/pull/17498))
* Add `__replace__` for dataclasses in 3.13 (Max Muoto, PR [17469](https://github.com/python/mypy/pull/17469))
* Fix help message for `--no-namespace-packages` (Raphael Krupinski, PR [17472](https://github.com/python/mypy/pull/17472))
* Fix typechecking for async generators (Danny Yang, PR [17452](https://github.com/python/mypy/pull/17452))
* Fix strict optional handling in attrs plugin (Ivan Levkivskyi, PR [17451](https://github.com/python/mypy/pull/17451))
* Allow mixing ParamSpec and TypeVarTuple in Generic (Ivan Levkivskyi, PR [17450](https://github.com/python/mypy/pull/17450))
* Improvements to `functools.partial` of types (Shantanu, PR [17898](https://github.com/python/mypy/pull/17898))
* Make ReadOnly TypedDict items covariant (Jukka Lehtosalo, PR [17904](https://github.com/python/mypy/pull/17904))
* Fix union callees with `functools.partial` (Jukka Lehtosalo, PR [17903](https://github.com/python/mypy/pull/17903))
* Improve handling of generic functions with `functools.partial` (Ivan Levkivskyi, PR [17925](https://github.com/python/mypy/pull/17925))

Typeshed Updates

Please see [git log](https://github.com/python/typeshed/commits/main?after=91a58b07cdd807b1d965e04ba85af2adab8bf924+0&branch=main&path=stdlib) for full list of standard library typeshed stub changes.

1.11.2

* Alternative fix for a union-like literal string (Ivan Levkivskyi, PR [17639](https://github.com/python/mypy/pull/17639))
* Unwrap `TypedDict` item types before storing (Ivan Levkivskyi, PR [17640](https://github.com/python/mypy/pull/17640))

Acknowledgements
Thanks to all mypy contributors who contributed to this release:

- Alex Waygood
- Alexander Leopold Shon
- Ali Hamdan
- Anders Kaseorg
- Ben Brown
- Bénédikt Tran
- bzoracler
- Christoph Tyralla
- Christopher Barber
- dexterkennedy
- gilesgc
- GiorgosPapoutsakis
- Ivan Levkivskyi
- Jelle Zijlstra
- Jukka Lehtosalo
- Marc Mueller
- Matthieu Devlin
- Michael R. Crusoe
- Nikita Sobolev
- Seo Sanghyeon
- Shantanu
- sobolevn
- Steven Troxler
- Tadeu Manoel
- Tamir Duberstein
- Tushar Sadhwani
- urnest
- Valentin Stanciu

I’d also like to thank my employer, Dropbox, for supporting mypy development.

1.11.1

* Fix `RawExpressionType.accept` crash with `--cache-fine-grained` (Anders Kaseorg, PR [17588](https://github.com/python/mypy/pull/17588))
* Fix PEP 604 isinstance caching (Shantanu, PR [17563](https://github.com/python/mypy/pull/17563))
* Fix `typing.TypeAliasType` being undefined on python < 3.12 (Nikita Sobolev, PR [17558](https://github.com/python/mypy/pull/17558))
* Fix `types.GenericAlias` lookup crash (Shantanu, PR [17543](https://github.com/python/mypy/pull/17543))

1.11

We’ve just uploaded mypy 1.11 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).

Support Python 3.12 Syntax for Generics (PEP 695)

Mypy now supports the new type parameter syntax introduced in Python 3.12 ([PEP 695](https://peps.python.org/pep-0695/)).
This feature is still experimental and must be enabled with the `--enable-incomplete-feature=NewGenericSyntax` flag, or with `enable_incomplete_feature = NewGenericSyntax` in the mypy configuration file.
We plan to enable this by default in the next mypy feature release.

This example demonstrates the new syntax:

python
Generic function
def f[T](x: T) -> T: ...

reveal_type(f(1))   Revealed type is 'int'

Generic class
class C[T]:
 def __init__(self, x: T) -> None:
    self.x = x

c = C('a')
reveal_type(c.x)   Revealed type is 'str'

Type alias
type A[T] = C[list[T]]


This feature was contributed by Jukka Lehtosalo.


Support for `functools.partial`

Mypy now type checks uses of `functools.partial`. Previously mypy would accept arbitrary arguments.

This example will now produce an error:

python
from functools import partial

def f(a: int, b: str) -> None: ...

g = partial(f, 1)

Argument has incompatible type "int"; expected "str"
g(11)


This feature was contributed by Shantanu (PR [16939](https://github.com/python/mypy/pull/16939)).


Stricter Checks for Untyped Overrides

Past mypy versions didn't check if untyped methods were compatible with overridden methods. This would result in false negatives. Now mypy performs these checks when using `--check-untyped-defs`.

For example, this now generates an error if using `--check-untyped-defs`:

python
class Base:
 def f(self, x: int = 0) -> None: ...

class Derived(Base):
  Signature incompatible with "Base"
 def f(self): ...


This feature was contributed by Steven Troxler (PR [17276](https://github.com/python/mypy/pull/17276)).


Type Inference Improvements

The new polymorphic inference algorithm introduced in mypy 1.5 is now used in more situations. This improves type inference involving generic higher-order functions, in particular.

This feature was contributed by Ivan Levkivskyi (PR [17348](https://github.com/python/mypy/pull/17348)).

Mypy now uses unions of tuple item types in certain contexts to enable more precise inferred types. Example:

python
for x in (1, 'x'):
  Previously inferred as 'object'
 reveal_type(x)   Revealed type is 'int | str'


This was also contributed by Ivan Levkivskyi (PR [17408](https://github.com/python/mypy/pull/17408)).


Improvements to Detection of Overlapping Overloads

The details of how mypy checks if two `overload` signatures are unsafely overlapping were overhauled. This both fixes some false positives, and allows mypy to detect additional unsafe signatures.

This feature was contributed by Ivan Levkivskyi (PR [17392](https://github.com/python/mypy/pull/17392)).


Better Support for Type Hints in Expressions

Mypy now allows more expressions that evaluate to valid type annotations in all expression contexts. The inferred types of these expressions are also sometimes more precise. Previously they were often `object`.

This example uses a union type that includes a callable type as an expression, and it no longer generates an error:

python
from typing import Callable

print(Callable[[], int] | None)   No error


This feature was contributed by Jukka Lehtosalo (PR [17404](https://github.com/python/mypy/pull/17404)).


Mypyc Improvements

Mypyc now supports the new syntax for generics introduced in Python 3.12 (see above). Another notable improvement is signficantly faster basic operations on `int` values.

* Support Python 3.12 syntax for generic functions and classes (Jukka Lehtosalo, PR [17357](https://github.com/python/mypy/pull/17357))
* Support Python 3.12 type alias syntax (Jukka Lehtosalo, PR [17384](https://github.com/python/mypy/pull/17384))
* Fix ParamSpec (Shantanu, PR [17309](https://github.com/python/mypy/pull/17309))
* Inline fast paths of integer unboxing operations (Jukka Lehtosalo, PR [17266](https://github.com/python/mypy/pull/17266))
* Inline tagged integer arithmetic and bitwise operations (Jukka Lehtosalo, PR [17265](https://github.com/python/mypy/pull/17265))
* Allow specifying primitives as pure (Jukka Lehtosalo, PR [17263](https://github.com/python/mypy/pull/17263))


Changes to Stubtest
* Ignore `_ios_support` (Alex Waygood, PR [17270](https://github.com/python/mypy/pull/17270))
* Improve support for Python 3.13 (Shantanu, PR [17261](https://github.com/python/mypy/pull/17261))


Changes to Stubgen
* Gracefully handle invalid `Optional` and recognize aliases to PEP 604 unions (Ali Hamdan, PR [17386](https://github.com/python/mypy/pull/17386))
* Fix for Python 3.13 (Jelle Zijlstra, PR [17290](https://github.com/python/mypy/pull/17290))
* Preserve enum value initialisers (Shantanu, PR [17125](https://github.com/python/mypy/pull/17125))


Miscellaneous New Features
* Add error format support and JSON output option via `--output json` (Tushar Sadhwani, PR [11396](https://github.com/python/mypy/pull/11396))
* Support `enum.member` in Python 3.11+ (Nikita Sobolev, PR [17382](https://github.com/python/mypy/pull/17382))
* Support `enum.nonmember` in Python 3.11+ (Nikita Sobolev, PR [17376](https://github.com/python/mypy/pull/17376))
* Support `namedtuple.__replace__` in Python 3.13 (Shantanu, PR [17259](https://github.com/python/mypy/pull/17259))
* Support `rename=True` in collections.namedtuple (Jelle Zijlstra, PR [17247](https://github.com/python/mypy/pull/17247))
* Add support for `__spec__` (Shantanu, PR [14739](https://github.com/python/mypy/pull/14739))


Changes to Error Reporting
* Mention `--enable-incomplete-feature=NewGenericSyntax` in messages (Shantanu, PR [17462](https://github.com/python/mypy/pull/17462))
* Do not report plugin-generated methods with `explicit-override` (sobolevn, PR [17433](https://github.com/python/mypy/pull/17433))
* Use and display namespaces for function type variables (Ivan Levkivskyi, PR [17311](https://github.com/python/mypy/pull/17311))
* Fix false positive for Final local scope variable in Protocol (GiorgosPapoutsakis, PR [17308](https://github.com/python/mypy/pull/17308))
* Use Never in more messages, use ambiguous in join (Shantanu, PR [17304](https://github.com/python/mypy/pull/17304))
* Log full path to config file in verbose output (dexterkennedy, PR [17180](https://github.com/python/mypy/pull/17180))
* Added `[prop-decorator]` code for unsupported property decorators (14461) (Christopher Barber, PR [16571](https://github.com/python/mypy/pull/16571))
* Suppress second error message with `:=` and `[truthy-bool]` (Nikita Sobolev, PR [15941](https://github.com/python/mypy/pull/15941))
* Generate error for assignment of functional Enum to variable of different name (Shantanu, PR [16805](https://github.com/python/mypy/pull/16805))
* Fix error reporting on cached run after uninstallation of third party library (Shantanu, PR [17420](https://github.com/python/mypy/pull/17420))


Fixes for Crashes
* Fix daemon crash on invalid type in TypedDict (Ivan Levkivskyi, PR [17495](https://github.com/python/mypy/pull/17495))
* Fix crash and bugs related to `partial()` (Ivan Levkivskyi, PR [17423](https://github.com/python/mypy/pull/17423))
* Fix crash when overriding with unpacked TypedDict (Ivan Levkivskyi, PR [17359](https://github.com/python/mypy/pull/17359))
* Fix crash on TypedDict unpacking for ParamSpec (Ivan Levkivskyi, PR [17358](https://github.com/python/mypy/pull/17358))
* Fix crash involving recursive union of tuples (Ivan Levkivskyi, PR [17353](https://github.com/python/mypy/pull/17353))
* Fix crash on invalid callable property override (Ivan Levkivskyi, PR [17352](https://github.com/python/mypy/pull/17352))
* Fix crash on unpacking self in NamedTuple (Ivan Levkivskyi, PR [17351](https://github.com/python/mypy/pull/17351))
* Fix crash on recursive alias with an optional type (Ivan Levkivskyi, PR [17350](https://github.com/python/mypy/pull/17350))
* Fix crash on type comment inside generic definitions (Bénédikt Tran, PR [16849](https://github.com/python/mypy/pull/16849))


Changes to Documentation
* Use inline config in documentation for optional error codes (Shantanu, PR [17374](https://github.com/python/mypy/pull/17374))
* Use lower-case generics in documentation (Seo Sanghyeon, PR [17176](https://github.com/python/mypy/pull/17176))
* Add documentation for show-error-code-links (GiorgosPapoutsakis, PR [17144](https://github.com/python/mypy/pull/17144))
* Update CONTRIBUTING.md to include commands for Windows (GiorgosPapoutsakis, PR [17142](https://github.com/python/mypy/pull/17142))


Other Notable Improvements and Fixes
* Fix ParamSpec inference against TypeVarTuple (Ivan Levkivskyi, PR [17431](https://github.com/python/mypy/pull/17431))
* Fix explicit type for `partial` (Ivan Levkivskyi, PR [17424](https://github.com/python/mypy/pull/17424))
* Always allow lambda calls (Ivan Levkivskyi, PR [17430](https://github.com/python/mypy/pull/17430))
* Fix isinstance checks with PEP 604 unions containing None (Shantanu, PR [17415](https://github.com/python/mypy/pull/17415))
* Fix self-referential upper bound in new-style type variables (Ivan Levkivskyi, PR [17407](https://github.com/python/mypy/pull/17407))
* Consider overlap between instances and callables (Ivan Levkivskyi, PR [17389](https://github.com/python/mypy/pull/17389))
* Allow new-style self-types in classmethods (Ivan Levkivskyi, PR [17381](https://github.com/python/mypy/pull/17381))
* Fix isinstance with type aliases to PEP 604 unions (Shantanu, PR [17371](https://github.com/python/mypy/pull/17371))
* Properly handle unpacks in overlap checks (Ivan Levkivskyi, PR [17356](https://github.com/python/mypy/pull/17356))
* Fix type application for classes with generic constructors (Ivan Levkivskyi, PR [17354](https://github.com/python/mypy/pull/17354))
* Update `typing_extensions` to >=4.6.0 to fix Python 3.12 error (Ben Brown, PR [17312](https://github.com/python/mypy/pull/17312))
* Avoid "does not return" error in lambda (Shantanu, PR [17294](https://github.com/python/mypy/pull/17294))
* Fix bug with descriptors in non-strict-optional mode (Max Murin, PR [17293](https://github.com/python/mypy/pull/17293))
* Don’t leak unreachability from lambda body to surrounding scope (Anders Kaseorg, PR [17287](https://github.com/python/mypy/pull/17287))
* Fix issues with non-ASCII characters on Windows (Alexander Leopold Shon, PR [17275](https://github.com/python/mypy/pull/17275))
* Fix for type narrowing of negative integer literals (gilesgc, PR [17256](https://github.com/python/mypy/pull/17256))
* Fix confusion between .py and .pyi files in mypy daemon (Valentin Stanciu, PR [17245](https://github.com/python/mypy/pull/17245))
* Fix type of `tuple[X, Y]` expression (urnest, PR [17235](https://github.com/python/mypy/pull/17235))
* Don't forget that a `TypedDict` was wrapped in `Unpack` after a `name-defined` error occurred (Christoph Tyralla, PR [17226](https://github.com/python/mypy/pull/17226))
* Mark annotated argument as having an explicit, not inferred type (bzoracler, PR [17217](https://github.com/python/mypy/pull/17217))
* Don't consider Enum private attributes as enum members (Ali Hamdan, PR [17182](https://github.com/python/mypy/pull/17182))
* Fix Literal strings containing pipe characters (Jelle Zijlstra, PR [17148](https://github.com/python/mypy/pull/17148))


Typeshed Updates

Please see [git log](https://github.com/python/typeshed/commits/main?after=6dda799d8ad1d89e0f8aad7ac41d2d34bd838ace+0&branch=main&path=stdlib) for full list of standard library typeshed stub changes.

1.10.1

- Fix error reporting on cached run after uninstallation of third party library (Shantanu, PR [17420](https://github.com/python/mypy/pull/17420))

Acknowledgements
Thanks to all mypy contributors who contributed to this release:

- Alex Waygood
- Ali Hamdan
- Edward Paget
- Evgeniy Slobodkin
- Hashem
- hesam
- Hugo van Kemenade
- Ihor
- James Braza
- Jelle Zijlstra
- jhance
- Jukka Lehtosalo
- Loïc Simon
- Marc Mueller
- Matthieu Devlin
- Michael R. Crusoe
- Nikita Sobolev
- Oskari Lehto
- Riccardo Di Maio
- Richard Si
- roberfi
- Roman Solomatin
- Sam Xifaras
- Shantanu
- Spencer Brown
- Srinivas Lade
- Tamir Duberstein
- youkaichao

I’d also like to thank my employer, Dropbox, for supporting mypy development.

1.10

We’ve just uploaded mypy 1.10 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).

Support TypeIs (PEP 742)

Mypy now supports `TypeIs` ([PEP 742](https://peps.python.org/pep-0742/)), which allows
functions to narrow the type of a value, similar to `isinstance()`. Unlike `TypeGuard`,
`TypeIs` can narrow in both the `if` and `else` branches of an if statement:

python
from typing_extensions import TypeIs

def is_str(s: object) -> TypeIs[str]:
 return isinstance(s, str)

def f(o: str | int) -> None:
 if is_str(o):
      Type of o is 'str'
     ...
 else:
      Type of o is 'int'
     ...


`TypeIs` will be added to the `typing` module in Python 3.13, but it
can be used on earlier Python versions by importing it from
`typing_extensions`.

This feature was contributed by Jelle Zijlstra (PR [16898](https://github.com/python/mypy/pull/16898)).

Support TypeVar Defaults (PEP 696)

[PEP 696](https://peps.python.org/pep-0696/) adds support for type parameter defaults.
Example:

python
from typing import Generic
from typing_extensions import TypeVar

T = TypeVar("T", default=int)

class C(Generic[T]):
...

x: C = ...
y: C[str] = ...
reveal_type(x)   C[int], because of the default
reveal_type(y)   C[str]


TypeVar defaults will be added to the `typing` module in Python 3.13, but they
can be used with earlier Python releases by importing `TypeVar` from
`typing_extensions`.

This feature was contributed by Marc Mueller (PR [16878](https://github.com/python/mypy/pull/16878)
and PR [16925](https://github.com/python/mypy/pull/16925)).

Support TypeAliasType (PEP 695)
As part of the initial steps towards implementing [PEP 695](https://peps.python.org/pep-0695/), mypy now supports `TypeAliasType`.
`TypeAliasType` provides a backport of the new `type` statement in Python 3.12.

python
type ListOrSet[T] = list[T] | set[T]


is equivalent to:

python
T = TypeVar("T")
ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,))


Example of use in mypy:

python
from typing_extensions import TypeAliasType, TypeVar

NewUnionType = TypeAliasType("NewUnionType", int | str)
x: NewUnionType = 42
y: NewUnionType = 'a'
z: NewUnionType = object()   error: Incompatible types in assignment (expression has type "object", variable has type "int | str")  [assignment]

T = TypeVar("T")
ListOrSet = TypeAliasType("ListOrSet", list[T] | set[T], type_params=(T,))
a: ListOrSet[int] = [1, 2]
b: ListOrSet[str] = {'a', 'b'}
c: ListOrSet[str] = 'test'   error: Incompatible types in assignment (expression has type "str", variable has type "list[str] | set[str]")  [assignment]


`TypeAliasType` was added to the `typing` module in Python 3.12, but it can be used with earlier Python releases by importing from `typing_extensions`.

This feature was contributed by Ali Hamdan (PR [16926](https://github.com/python/mypy/pull/16926), PR [17038](https://github.com/python/mypy/pull/17038) and PR [17053](https://github.com/python/mypy/pull/17053))

Detect Additional Unsafe Uses of super()

Mypy will reject unsafe uses of `super()` more consistently, when the target has a
trivial (empty) body. Example:

python
class Proto(Protocol):
 def method(self) -> int: ...

class Sub(Proto):
 def method(self) -> int:
     return super().meth()   Error (unsafe)


This feature was contributed by Shantanu (PR [16756](https://github.com/python/mypy/pull/16756)).

Stubgen Improvements
- Preserve empty tuple annotation (Ali Hamdan, PR [16907](https://github.com/python/mypy/pull/16907))
- Add support for PEP 570 positional-only parameters (Ali Hamdan, PR [16904](https://github.com/python/mypy/pull/16904))
- Replace obsolete typing aliases with builtin containers (Ali Hamdan, PR [16780](https://github.com/python/mypy/pull/16780))
- Fix generated dataclass `__init__` signature (Ali Hamdan, PR [16906](https://github.com/python/mypy/pull/16906))

Mypyc Improvements

- Provide an easier way to define IR-to-IR transforms (Jukka Lehtosalo, PR [16998](https://github.com/python/mypy/pull/16998))
- Implement lowering pass and add primitives for int (in)equality (Jukka Lehtosalo, PR [17027](https://github.com/python/mypy/pull/17027))
- Implement lowering for remaining tagged integer comparisons (Jukka Lehtosalo, PR [17040](https://github.com/python/mypy/pull/17040))
- Optimize away some bool/bit registers (Jukka Lehtosalo, PR [17022](https://github.com/python/mypy/pull/17022))
- Remangle redefined names produced by async with (Richard Si, PR [16408](https://github.com/python/mypy/pull/16408))
- Optimize TYPE_CHECKING to False at Runtime (Srinivas Lade, PR [16263](https://github.com/python/mypy/pull/16263))
- Fix compilation of unreachable comprehensions (Richard Si, PR [15721](https://github.com/python/mypy/pull/15721))
- Don't crash on non-inlinable final local reads (Richard Si, PR [15719](https://github.com/python/mypy/pull/15719))

Documentation Improvements
- Import `TypedDict` from `typing` instead of `typing_extensions` (Riccardo Di Maio, PR [16958](https://github.com/python/mypy/pull/16958))
- Add missing `mutable-override` to section title (James Braza, PR [16886](https://github.com/python/mypy/pull/16886))

Error Reporting Improvements

- Use lower-case generics more consistently in error messages (Jukka Lehtosalo, PR [17035](https://github.com/python/mypy/pull/17035))

Other Notable Changes and Fixes
- Fix incorrect inferred type when accessing descriptor on union type (Matthieu Devlin, PR [16604](https://github.com/python/mypy/pull/16604))
- Fix crash when expanding invalid `Unpack` in a `Callable` alias (Ali Hamdan, PR [17028](https://github.com/python/mypy/pull/17028))
- Fix false positive when string formatting with string enum (roberfi, PR [16555](https://github.com/python/mypy/pull/16555))
- Narrow individual items when matching a tuple to a sequence pattern (Loïc Simon, PR [16905](https://github.com/python/mypy/pull/16905))
- Fix false positive from type variable within TypeGuard or TypeIs (Evgeniy Slobodkin, PR [17071](https://github.com/python/mypy/pull/17071))
- Improve `yield from` inference for unions of generators (Shantanu, PR [16717](https://github.com/python/mypy/pull/16717))
- Fix emulating hash method logic in `attrs` classes (Hashem, PR [17016](https://github.com/python/mypy/pull/17016))
- Add reverted typeshed commit that uses `ParamSpec` for `functools.wraps` (Tamir Duberstein, PR [16942](https://github.com/python/mypy/pull/16942))
- Fix type narrowing for `types.EllipsisType` (Shantanu, PR [17003](https://github.com/python/mypy/pull/17003))
- Fix single item enum match type exhaustion (Oskari Lehto, PR [16966](https://github.com/python/mypy/pull/16966))
- Improve type inference with empty collections (Marc Mueller, PR [16994](https://github.com/python/mypy/pull/16994))
- Fix override checking for decorated property (Shantanu, PR [16856](https://github.com/python/mypy/pull/16856))
- Fix narrowing on match with function subject (Edward Paget, PR [16503](https://github.com/python/mypy/pull/16503))
- Allow `+N` within `Literal[...]` (Spencer Brown, PR [16910](https://github.com/python/mypy/pull/16910))
- Experimental: Support TypedDict within `type[...]` (Marc Mueller, PR [16963](https://github.com/python/mypy/pull/16963))
- Experimtental: Fix issue with TypedDict with optional keys in `type[...]` (Marc Mueller, PR [17068](https://github.com/python/mypy/pull/17068))

Typeshed Updates

Please see [git log](https://github.com/python/typeshed/commits/main?after=6dda799d8ad1d89e0f8aad7ac41d2d34bd838ace+0&branch=main&path=stdlib) for full list of standard library typeshed stub changes.

1.9

We’ve just uploaded mypy 1.9 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).

Breaking Changes

Because the version of typeshed we use in mypy 1.9 doesn't support 3.7, neither does mypy 1.9. (Jared Hance, PR [16883](https://github.com/python/mypy/pull/16883))

We are planning to enable
[local partial types](https://mypy.readthedocs.io/en/stable/command_line.html#cmdoption-mypy-local-partial-types) (enabled via the
`--local-partial-types` flag) later this year by default. This change
was announced years ago, but now it's finally happening. This is a
major backward-incompatible change, so we'll probably include it as
part of the upcoming mypy 2.0 release. This makes daemon and
non-daemon mypy runs have the same behavior by default.

Local partial types can also be enabled in the mypy config file:

local_partial_types = True


We are looking at providing a tool to make it easier to migrate
projects to use `--local-partial-types`, but it's not yet clear whether
this is practical. The migration usually involves adding some
explicit type annotations to module-level and class-level variables.

Basic Support for Type Parameter Defaults (PEP 696)

This release contains new experimental support for type parameter
defaults ([PEP 696](https://peps.python.org/pep-0696)). Please try it
out! This feature was contributed by Marc Mueller.

Since this feature will be officially introduced in the next Python
feature release (3.13), you will need to import `TypeVar`, `ParamSpec`
or `TypeVarTuple` from `typing_extensions` to use defaults for now.

This example adapted from the PEP defines a default for `BotT`:
python
from typing import Generic
from typing_extensions import TypeVar

class Bot: ...

BotT = TypeVar("BotT", bound=Bot, default=Bot)

class Context(Generic[BotT]):
 bot: BotT

class MyBot(Bot): ...

type is Bot (the default)
reveal_type(Context().bot)
type is MyBot
reveal_type(Context[MyBot]().bot)


Type-checking Improvements
* Fix missing type store for overloads (Marc Mueller, PR [16803](https://github.com/python/mypy/pull/16803))
* Fix `'WriteToConn' object has no attribute 'flush'` (Charlie Denton, PR [16801](https://github.com/python/mypy/pull/16801))
* Improve TypeAlias error messages (Marc Mueller, PR [16831](https://github.com/python/mypy/pull/16831))
* Support narrowing unions that include `type[None]` (Christoph Tyralla, PR [16315](https://github.com/python/mypy/pull/16315))
* Support TypedDict functional syntax as class base type (anniel-stripe, PR [16703](https://github.com/python/mypy/pull/16703))
* Accept multiline quoted annotations (Shantanu, PR [16765](https://github.com/python/mypy/pull/16765))
* Allow unary + in `Literal` (Jelle Zijlstra, PR [16729](https://github.com/python/mypy/pull/16729))
* Substitute type variables in return type of static methods (Kouroche Bouchiat, PR [16670](https://github.com/python/mypy/pull/16670))
* Consider TypeVarTuple to be invariant (Marc Mueller, PR [16759](https://github.com/python/mypy/pull/16759))
* Add `alias` support to `field()` in `attrs` plugin (Nikita Sobolev, PR [16610](https://github.com/python/mypy/pull/16610))
* Improve attrs hashability detection (Tin Tvrtković, PR [16556](https://github.com/python/mypy/pull/16556))

Performance Improvements

* Speed up finding function type variables (Jukka Lehtosalo, PR [16562](https://github.com/python/mypy/pull/16562))

Documentation Updates

* Document supported values for `--enable-incomplete-feature` in "mypy --help" (Froger David, PR [16661](https://github.com/python/mypy/pull/16661))
* Update new type system discussion links (thomaswhaley, PR [16841](https://github.com/python/mypy/pull/16841))
* Add missing class instantiation to cheat sheet (Aleksi Tarvainen, PR [16817](https://github.com/python/mypy/pull/16817))
* Document how evil `--no-strict-optional` is (Shantanu, PR [16731](https://github.com/python/mypy/pull/16731))
* Improve mypy daemon documentation note about local partial types (Makonnen Makonnen, PR [16782](https://github.com/python/mypy/pull/16782))
* Fix numbering error (Stefanie Molin, PR [16838](https://github.com/python/mypy/pull/16838))
* Various documentation improvements (Shantanu, PR [16836](https://github.com/python/mypy/pull/16836))

Stubtest Improvements
* Ignore private function/method parameters when they are missing from the stub (private parameter names start with a single underscore and have a default) (PR [16507](https://github.com/python/mypy/pull/16507))
* Ignore a new protocol dunder (Alex Waygood, PR [16895](https://github.com/python/mypy/pull/16895))
* Private parameters can be omitted (Sebastian Rittau, PR [16507](https://github.com/python/mypy/pull/16507))
* Add support for setting enum members to "..." (Jelle Zijlstra, PR [16807](https://github.com/python/mypy/pull/16807))
* Adjust symbol table logic (Shantanu, PR [16823](https://github.com/python/mypy/pull/16823))
* Fix posisitional-only handling in overload resolution (Shantanu, PR [16750](https://github.com/python/mypy/pull/16750))

Stubgen Improvements
* Fix crash on star unpack of TypeVarTuple (Ali Hamdan, PR [16869](https://github.com/python/mypy/pull/16869))
* Use PEP 604 unions everywhere (Ali Hamdan, PR [16519](https://github.com/python/mypy/pull/16519))
* Do not ignore property deleter (Ali Hamdan, PR [16781](https://github.com/python/mypy/pull/16781))
* Support type stub generation for `staticmethod` (WeilerMarcel, PR [14934](https://github.com/python/mypy/pull/14934))

Acknowledgements

​Thanks to all mypy contributors who contributed to this release:

- Aleksi Tarvainen
- Alex Waygood
- Ali Hamdan
- anniel-stripe
- Charlie Denton
- Christoph Tyralla
- Dheeraj
- Fabian Keller
- Fabian Lewis
- Froger David
- Ihor
- Jared Hance
- Jelle Zijlstra
- Jukka Lehtosalo
- Kouroche Bouchiat
- Lukas Geiger
- Maarten Huijsmans
- Makonnen Makonnen
- Marc Mueller
- Nikita Sobolev
- Sebastian Rittau
- Shantanu
- Stefanie Molin
- Stephen Morton
- thomaswhaley
- Tin Tvrtković
- WeilerMarcel
- Wesley Collin Wright
- zipperer

I’d also like to thank my employer, Dropbox, for supporting mypy development.

1.8

We’ve just uploaded mypy 1.8 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)). 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](http://mypy.readthedocs.io).

Type-checking Improvements
* Do not intersect types in isinstance checks if at least one is final (Christoph Tyralla, PR [16330](https://github.com/python/mypy/pull/16330))
* Detect that `final` class without `__bool__` cannot have falsey instances (Ilya Priven, PR [16566](https://github.com/python/mypy/pull/16566))
* Do not allow `TypedDict` classes with extra keywords (Nikita Sobolev, PR [16438](https://github.com/python/mypy/pull/16438))
* Do not allow class-level keywords for `NamedTuple` (Nikita Sobolev, PR [16526](https://github.com/python/mypy/pull/16526))
* Make imprecise constraints handling more robust (Ivan Levkivskyi, PR [16502](https://github.com/python/mypy/pull/16502))
* Fix strict-optional in extending generic TypedDict (Ivan Levkivskyi, PR [16398](https://github.com/python/mypy/pull/16398))
* Allow type ignores of PEP 695 constructs (Shantanu, PR [16608](https://github.com/python/mypy/pull/16608))
* Enable `type_check_only` support for `TypedDict` and `NamedTuple` (Nikita Sobolev, PR [16469](https://github.com/python/mypy/pull/16469))

Performance Improvements
* Add fast path to analyzing special form assignments (Jukka Lehtosalo, PR [16561](https://g

@pyup-bot pyup-bot mentioned this pull request Dec 30, 2024
Closed
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees
No one assigned
Labels
dependency update
Projects
None yet
Milestone
No milestone
Development

Successfully merging this pull request may close these issues.
1 participant
@pyup-bot