Merge branch 'master' into feat/exhaustive-match

Author: Don-Burns

docs/source/command_line.rst

@@ -593,12 +593,58 @@ of the above sections.
     This flag causes mypy to suppress errors caused by not being able to fully
     infer the types of global and class variables.
 
-.. option:: --allow-redefinition
+.. option:: --allow-redefinition-new
 
     By default, mypy won't allow a variable to be redefined with an
-    unrelated type. This flag enables redefinition of a variable with an
+    unrelated type. This *experimental* flag enables the redefinition of
+    unannotated variables with an arbitrary type. You will also need to enable
+    :option:`--local-partial-types <mypy --local-partial-types>`.
+    Example:
+
+    .. code-block:: python
+
+        def maybe_convert(n: int, b: bool) -> int | str:
+            if b:
+                x = str(n)  # Assign "str"
+            else:
+                x = n       # Assign "int"
+            # Type of "x" is "int | str" here.
+            return x
+
+    Without the new flag, mypy only supports inferring optional types
+    (``X | None``) from multiple assignments. With this option enabled,
+    mypy can infer arbitrary union types.
+
+    This also enables an unannotated variable to have different types in different
+    code locations:
+
+    .. code-block:: python
+
+        if check():
+            for x in range(n):
+                # Type of "x" is "int" here.
+                ...
+        else:
+            for x in ['a', 'b']:
+                # Type of "x" is "str" here.
+                ...
+
+    Note: We are planning to turn this flag on by default in a future mypy
+    release, along with :option:`--local-partial-types <mypy --local-partial-types>`.
+    The feature is still experimental, and the semantics may still change.
+
+.. option:: --allow-redefinition
+
+    This is an older variant of
+    :option:`--allow-redefinition-new <mypy --allow-redefinition-new>`.
+    This flag enables redefinition of a variable with an
     arbitrary type *in some contexts*: only redefinitions within the
     same block and nesting depth as the original definition are allowed.
+
+    We have no plans to remove this flag, but we expect that
+    :option:`--allow-redefinition-new <mypy --allow-redefinition-new>`
+    will replace this flag for new use cases eventually.
+
     Example where this can be useful:
 
     .. code-block:: python

docs/source/config_file.rst

@@ -713,6 +713,44 @@ section of the command line docs.
     Causes mypy to suppress errors caused by not being able to fully
     infer the types of global and class variables.
 
+.. confval:: allow_redefinition_new
+
+    :type: boolean
+    :default: False
+
+    By default, mypy won't allow a variable to be redefined with an
+    unrelated type. This *experimental* flag enables the redefinition of
+    unannotated variables with an arbitrary type. You will also need to enable
+    :confval:`local_partial_types`.
+    Example:
+
+    .. code-block:: python
+
+        def maybe_convert(n: int, b: bool) -> int | str:
+            if b:
+                x = str(n)  # Assign "str"
+            else:
+                x = n       # Assign "int"
+            # Type of "x" is "int | str" here.
+            return x
+
+    This also enables an unannotated variable to have different types in different
+    code locations:
+
+    .. code-block:: python
+
+        if check():
+            for x in range(n):
+                # Type of "x" is "int" here.
+                ...
+        else:
+            for x in ['a', 'b']:
+                # Type of "x" is "str" here.
+                ...
+
+    Note: We are planning to turn this flag on by default in a future mypy
+    release, along with :confval:`local_partial_types`.
+
 .. confval:: allow_redefinition
 
     :type: boolean
@@ -746,6 +784,7 @@ section of the command line docs.
 
     Disallows inferring variable type for ``None`` from two assignments in different scopes.
     This is always implicitly enabled when using the :ref:`mypy daemon <mypy_daemon>`.
+    This will be enabled by default in a future mypy release.
 
 .. confval:: disable_error_code
 

docs/source/generics.rst

@@ -93,7 +93,7 @@ Using ``Stack`` is similar to built-in container types:
    stack.push('x')
 
    stack2: Stack[str] = Stack()
-   stack2.append('x')
+   stack2.push('x')
 
 Construction of instances of generic types is type checked (Python 3.12 syntax):
 

misc/typeshed_patches/0001-Partially-revert-Clean-up-argparse-hacks.patch

@@ -1,4 +1,4 @@
-From b5f2cc9633f9f6cd9326eee96a32efb3aff70701 Mon Sep 17 00:00:00 2001
+From 05f351f6a37fe8b73c698c348bf6aa5108363049 Mon Sep 17 00:00:00 2001
 From: Marc Mueller <[email protected]>
 Date: Sat, 15 Feb 2025 20:11:06 +0100
 Subject: [PATCH] Partially revert Clean up argparse hacks
@@ -8,7 +8,7 @@ Subject: [PATCH] Partially revert Clean up argparse hacks
  1 file changed, 5 insertions(+), 3 deletions(-)
 
 diff --git a/mypy/typeshed/stdlib/argparse.pyi b/mypy/typeshed/stdlib/argparse.pyi
-index 029bfeefe..9dbd8c308 100644
+index 95ad6c7da..79e6cfde1 100644
 --- a/mypy/typeshed/stdlib/argparse.pyi
 +++ b/mypy/typeshed/stdlib/argparse.pyi
 @@ -2,7 +2,7 @@ import sys
@@ -20,7 +20,7 @@ index 029bfeefe..9dbd8c308 100644
  from typing_extensions import Self, TypeAlias, deprecated
 
  __all__ = [
-@@ -38,7 +38,9 @@ ONE_OR_MORE: Final = "+"
+@@ -36,7 +36,9 @@ ONE_OR_MORE: Final = "+"
  OPTIONAL: Final = "?"
  PARSER: Final = "A..."
  REMAINDER: Final = "..."
@@ -31,7 +31,7 @@ index 029bfeefe..9dbd8c308 100644
  ZERO_OR_MORE: Final = "*"
  _UNRECOGNIZED_ARGS_ATTR: Final = "_unrecognized_args"  # undocumented
 
-@@ -81,7 +83,7 @@ class _ActionsContainer:
+@@ -79,7 +81,7 @@ class _ActionsContainer:
          # more precisely, Literal["?", "*", "+", "...", "A...", "==SUPPRESS=="],
          # but using this would make it hard to annotate callers that don't use a
          # literal argument and for subclasses to override this method.
@@ -41,5 +41,5 @@ index 029bfeefe..9dbd8c308 100644
          default: Any = ...,
          type: _ActionType = ...,
 -- 
-2.48.1
+2.49.0
 

misc/typeshed_patches/0001-Remove-use-of-LiteralString-in-builtins-13743.patch

@@ -1,4 +1,4 @@
-From b4259edd94188f9e4cc77a22e768eea183a32053 Mon Sep 17 00:00:00 2001
+From e6995c91231e1915eba43a29a22dd4cbfaf9e08e Mon Sep 17 00:00:00 2001
 From: Shantanu <[email protected]>
 Date: Mon, 26 Sep 2022 12:55:07 -0700
 Subject: [PATCH] Remove use of LiteralString in builtins (#13743)
@@ -8,18 +8,18 @@ Subject: [PATCH] Remove use of LiteralString in builtins (#13743)
  1 file changed, 1 insertion(+), 99 deletions(-)
 
 diff --git a/mypy/typeshed/stdlib/builtins.pyi b/mypy/typeshed/stdlib/builtins.pyi
-index 63c53a5f6..d55042b56 100644
+index 00728f42d..ea77a730f 100644
 --- a/mypy/typeshed/stdlib/builtins.pyi
 +++ b/mypy/typeshed/stdlib/builtins.pyi
-@@ -63,7 +63,6 @@ from typing import (  # noqa: Y022
+@@ -63,7 +63,6 @@ from typing import (  # noqa: Y022,UP035
  from typing_extensions import (  # noqa: Y023
      Concatenate,
      Literal,
 -    LiteralString,
      ParamSpec,
      Self,
      TypeAlias,
-@@ -438,31 +437,16 @@ class str(Sequence[str]):
+@@ -453,31 +452,16 @@ class str(Sequence[str]):
      def __new__(cls, object: object = ...) -> Self: ...
      @overload
      def __new__(cls, object: ReadableBuffer, encoding: str = ..., errors: str = ...) -> Self: ...
@@ -51,7 +51,7 @@ index 63c53a5f6..d55042b56 100644
      def format(self, *args: object, **kwargs: object) -> str: ...
      def format_map(self, mapping: _FormatMapMapping, /) -> str: ...
      def index(self, sub: str, start: SupportsIndex | None = ..., end: SupportsIndex | None = ..., /) -> int: ...
-@@ -478,99 +462,35 @@ class str(Sequence[str]):
+@@ -493,98 +477,34 @@ class str(Sequence[str]):
      def isspace(self) -> bool: ...
      def istitle(self) -> bool: ...
      def isupper(self) -> bool: ...
@@ -89,16 +89,15 @@ index 63c53a5f6..d55042b56 100644
 -        ) -> LiteralString: ...
 -        @overload
          def replace(self, old: str, new: str, count: SupportsIndex = -1, /) -> str: ...  # type: ignore[misc]
-     if sys.version_info >= (3, 9):
--        @overload
--        def removeprefix(self: LiteralString, prefix: LiteralString, /) -> LiteralString: ...
--        @overload
-         def removeprefix(self, prefix: str, /) -> str: ...  # type: ignore[misc]
--        @overload
--        def removesuffix(self: LiteralString, suffix: LiteralString, /) -> LiteralString: ...
--        @overload
-         def removesuffix(self, suffix: str, /) -> str: ...  # type: ignore[misc]
 
+-    @overload
+-    def removeprefix(self: LiteralString, prefix: LiteralString, /) -> LiteralString: ...
+-    @overload
+     def removeprefix(self, prefix: str, /) -> str: ...  # type: ignore[misc]
+-    @overload
+-    def removesuffix(self: LiteralString, suffix: LiteralString, /) -> LiteralString: ...
+-    @overload
+     def removesuffix(self, suffix: str, /) -> str: ...  # type: ignore[misc]
      def rfind(self, sub: str, start: SupportsIndex | None = ..., end: SupportsIndex | None = ..., /) -> int: ...
      def rindex(self, sub: str, start: SupportsIndex | None = ..., end: SupportsIndex | None = ..., /) -> int: ...
 -    @overload
@@ -151,7 +150,7 @@ index 63c53a5f6..d55042b56 100644
      def zfill(self, width: SupportsIndex, /) -> str: ...  # type: ignore[misc]
      @staticmethod
      @overload
-@@ -581,39 +501,21 @@ class str(Sequence[str]):
+@@ -595,39 +515,21 @@ class str(Sequence[str]):
      @staticmethod
      @overload
      def maketrans(x: str, y: str, z: str, /) -> dict[int, int | None]: ...
@@ -193,5 +192,5 @@ index 63c53a5f6..d55042b56 100644
      def __getnewargs__(self) -> tuple[str]: ...
 
 -- 
-2.47.0
+2.49.0