Merge branch 'master' into pythongh-16649-type-comments-and-constrain…

…ed-generics

.github/workflows/build_wheels.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.11'
       - name: Trigger script

.github/workflows/docs.yml

@@ -34,7 +34,7 @@ jobs:
       VERIFY_MYPY_ERROR_CODES: 1
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: '3.8'
       - name: Install tox

.github/workflows/mypy_primer.yml

@@ -37,7 +37,7 @@ jobs:
         with:
           path: mypy_to_test
           fetch-depth: 0
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: "3.10"
       - name: Install dependencies

.github/workflows/mypy_primer_comment.yml

@@ -44,7 +44,7 @@ jobs:
 
       - name: Post comment
         id: post-comment
-        uses: actions/github-script@v6
+        uses: actions/github-script@v7
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |

.github/workflows/sync_typeshed.yml

@@ -20,7 +20,7 @@ jobs:
           fetch-depth: 0
         # TODO: use whatever solution ends up working for
         # https://github.com/python/typeshed/issues/8434
-      - uses: actions/setup-python@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: "3.10"
       - name: git config

.github/workflows/test.yml

@@ -120,7 +120,7 @@ jobs:
       PYTEST_ADDOPTS: --color=yes
     steps:
     - uses: actions/checkout@v4
-    - uses: actions/setup-python@v4
+    - uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.python }}
         architecture: ${{ matrix.arch }}

.github/workflows/test_stubgenc.yml

@@ -30,7 +30,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Setup 🐍 3.8
-      uses: actions/setup-python@v4
+      uses: actions/setup-python@v5
       with:
         python-version: 3.8
 

.pre-commit-config.yaml

@@ -11,7 +11,7 @@ repos:
       - id: black
         exclude: '^(test-data/)'
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.1.15  # must match test-requirements.txt
+    rev: v0.2.0  # must match test-requirements.txt
     hooks:
       - id: ruff
         args: [--exit-non-zero-on-fix]

CHANGELOG.md

@@ -1,6 +1,141 @@
 # Mypy Release Notes
 
-## Next release
+## Mypy 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.
 
 ## Mypy 1.8
 

docs/source/cheat_sheet_py3.rst

@@ -152,6 +152,8 @@ Classes
 
 .. code-block:: python
 
+   from typing import ClassVar
+
    class BankAccount:
        # The "__init__" method doesn't return anything, so it gets return
        # type "None" just like any other method that doesn't return anything

docs/source/common_issues.rst

@@ -541,7 +541,7 @@ Consider this example:
 
 .. code-block:: python
 
-   from typing_extensions import Protocol
+   from typing import Protocol
 
    class P(Protocol):
        x: float
@@ -561,7 +561,7 @@ the protocol definition:
 
 .. code-block:: python
 
-   from typing_extensions import Protocol
+   from typing import Protocol
 
    class P(Protocol):
        @property

docs/source/error_code_list.rst

@@ -537,7 +537,7 @@ Example:
 
 .. code-block:: python
 
-    from typing_extensions import TypedDict
+    from typing import TypedDict
 
     class Point(TypedDict):
         x: int
@@ -562,7 +562,7 @@ to have been validated at the point of construction. Example:
 
 .. code-block:: python
 
-    from typing_extensions import TypedDict
+    from typing import TypedDict
 
     class Point(TypedDict):
         x: int
@@ -868,7 +868,7 @@ the return type affects which lines mypy thinks are reachable after a
 ``True`` may swallow exceptions. An imprecise return type can result
 in mysterious errors reported near ``with`` statements.
 
-To fix this, use either ``typing_extensions.Literal[False]`` or
+To fix this, use either ``typing.Literal[False]`` or
 ``None`` as the return type. Returning ``None`` is equivalent to
 returning ``False`` in this context, since both are treated as false
 values.
@@ -897,7 +897,7 @@ You can use ``Literal[False]`` to fix the error:
 
 .. code-block:: python
 
-   from typing_extensions import Literal
+   from typing import Literal
 
    class MyContext:
        ...

docs/source/error_code_list2.rst

@@ -484,11 +484,11 @@ Example:
 
 .. _code-mutable-override:
 
-Check that overrides of mutable attributes are safe
----------------------------------------------------
+Check that overrides of mutable attributes are safe [mutable-override]
+----------------------------------------------------------------------
 
-This will enable the check for unsafe overrides of mutable attributes. For
-historical reasons, and because this is a relatively common pattern in Python,
+`mutable-override` will enable the check for unsafe overrides of mutable attributes.
+For historical reasons, and because this is a relatively common pattern in Python,
 this check is not enabled by default. The example below is unsafe, and will be
 flagged when this error code is enabled:
 
@@ -555,3 +555,19 @@ Correct usage:
 
 When this code is enabled, using ``reveal_locals`` is always an error,
 because there's no way one can import it.
+
+.. _code-narrowed-type-not-subtype:
+
+Check that ``TypeIs`` narrows types [narrowed-type-not-subtype]
+---------------------------------------------------------------
+
+:pep:`742` requires that when ``TypeIs`` is used, the narrowed
+type must be a subtype of the original type::
+
+    from typing_extensions import TypeIs
+
+    def f(x: int) -> TypeIs[str]:  # Error, str is not a subtype of int
+        ...
+
+    def g(x: object) -> TypeIs[str]:  # OK
+        ...

docs/source/generics.rst

@@ -770,8 +770,7 @@ protocols mostly follow the normal rules for generic classes. Example:
 
 .. code-block:: python
 
-   from typing import TypeVar
-   from typing_extensions import Protocol
+   from typing import Protocol, TypeVar
 
    T = TypeVar('T')
 

docs/source/protocols.rst

@@ -9,7 +9,7 @@ compatible as types: nominal subtyping and structural subtyping.
 *Nominal* subtyping is strictly based on the class hierarchy. If class ``Dog``
 inherits class ``Animal``, it's a subtype of ``Animal``. Instances of ``Dog``
 can be used when ``Animal`` instances are expected. This form of subtyping
-subtyping is what Python's type system predominantly uses: it's easy to
+is what Python's type system predominantly uses: it's easy to
 understand and produces clear and concise error messages, and matches how the
 native :py:func:`isinstance <isinstance>` check works -- based on class
 hierarchy.
@@ -68,8 +68,7 @@ class:
 
 .. code-block:: python
 
-   from typing import Iterable
-   from typing_extensions import Protocol
+   from typing import Iterable, Protocol
 
    class SupportsClose(Protocol):
        # Empty method body (explicit '...')
@@ -226,8 +225,7 @@ such as trees and linked lists:
 
 .. code-block:: python
 
-   from typing import TypeVar, Optional
-   from typing_extensions import Protocol
+   from typing import TypeVar, Optional, Protocol
 
    class TreeLike(Protocol):
        value: int
@@ -255,7 +253,7 @@ rudimentary support for runtime structural checks:
 
 .. code-block:: python
 
-   from typing_extensions import Protocol, runtime_checkable
+   from typing import Protocol, runtime_checkable
 
    @runtime_checkable
    class Portable(Protocol):
@@ -298,8 +296,7 @@ member:
 
 .. code-block:: python
 
-   from typing import Optional, Iterable
-   from typing_extensions import Protocol
+   from typing import Optional, Iterable, Protocol
 
    class Combiner(Protocol):
        def __call__(self, *vals: bytes, maxlen: Optional[int] = None) -> list[bytes]: ...
@@ -323,8 +320,7 @@ a double underscore prefix is used. For example:
 
 .. code-block:: python
 
-   from typing import Callable, TypeVar
-   from typing_extensions import Protocol
+   from typing import Callable, Protocol, TypeVar
 
    T = TypeVar('T')
 

docs/source/stubs.rst

@@ -114,7 +114,7 @@ For example:
 
 .. code-block:: python
 
-    from typing_extensions import Protocol
+    from typing import Protocol
 
     class Resource(Protocol):
         def ok_1(self, foo: list[str] = ...) -> None: ...