Merge remote-tracking branch 'upstream/master' into 3.8-collections-i…

…mports

.github/workflows/mypy_primer.yml

@@ -74,9 +74,9 @@ jobs:
         name: Save PR number
         run: |
           echo ${{ github.event.pull_request.number }} | tee pr_number.txt
-      - if: ${{ matrix.shard-index == 0 }}
-        name: Upload mypy_primer diff + PR number
+      - name: Upload mypy_primer diff + PR number
         uses: actions/upload-artifact@v4
+        if: ${{ matrix.shard-index == 0 }}
         with:
           name: mypy_primer_diffs-${{ matrix.shard-index }}
           path: |

.github/workflows/mypy_primer_comment.yml

@@ -48,7 +48,7 @@ jobs:
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
-            const MAX_CHARACTERS = 30000
+            const MAX_CHARACTERS = 50000
             const MAX_CHARACTERS_PER_PROJECT = MAX_CHARACTERS / 3
 
             const fs = require('fs')

.pre-commit-config.yaml

@@ -1,27 +1,27 @@
 exclude: '^(mypyc/external/)|(mypy/typeshed/)|misc/typeshed_patches'  # Exclude all vendored code from lints
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.5.0
+    rev: v5.0.0
     hooks:
       - id: trailing-whitespace
       - id: end-of-file-fixer
   - repo: https://github.com/psf/black-pre-commit-mirror
-    rev: 24.8.0
+    rev: 24.10.0
     hooks:
       - id: black
         exclude: '^(test-data/)'
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.9
+    rev: v0.8.4
     hooks:
       - id: ruff
         args: [--exit-non-zero-on-fix]
   - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.29.4
+    rev: 0.30.0
     hooks:
       - id: check-dependabot
       - id: check-github-workflows
   - repo: https://github.com/rhysd/actionlint
-    rev: v1.7.3
+    rev: v1.7.4
     hooks:
       - id: actionlint
         args: [

CHANGELOG.md

@@ -2,7 +2,25 @@
 
 ## Next release
 
-...
+### `--strict-bytes`
+
+By default, mypy treats an annotation of ``bytes`` as permitting ``bytearray`` and ``memoryview``.
+[PEP 688](https://peps.python.org/pep-0688) specified the removal of this special case.
+Use this flag to disable this behavior. `--strict-bytes` will be enabled by default in **mypy 2.0**.
+
+Contributed by Ali Hamdan (PR [18137](https://github.com/python/mypy/pull/18263/)) and
+Shantanu Jain (PR [13952](https://github.com/python/mypy/pull/13952)).
+
+### Improvements to partial type handling in loops
+
+This change results in mypy better modelling control flow within loops and hence detecting several
+issues it previously did not detect. In some cases, this change may require use of an additional
+explicit annotation of a variable.
+
+Contributed by Christoph Tyralla (PR [18180](https://github.com/python/mypy/pull/18180)).
+
+(Speaking of partial types, another reminder that mypy plans on enabling `--local-partial-types`
+by default in **mypy 2.0**).
 
 ## Mypy 1.14
 

mypy/checkexpr.py

@@ -5346,9 +5346,10 @@ def visit_lambda_expr(self, e: LambdaExpr) -> Type:
             self.chk.return_types.append(AnyType(TypeOfAny.special_form))
             # Type check everything in the body except for the final return
             # statement (it can contain tuple unpacking before return).
-            with self.chk.binder.frame_context(
-                can_skip=True, fall_through=0
-            ), self.chk.scope.push_function(e):
+            with (
+                self.chk.binder.frame_context(can_skip=True, fall_through=0),
+                self.chk.scope.push_function(e),
+            ):
                 # Lambdas can have more than one element in body,
                 # when we add "fictional" AssignmentStatement nodes, like in:
                 # `lambda (a, b): a`

mypy/fastparse.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import copy
 import re
 import sys
 import warnings
@@ -242,13 +241,6 @@ def parse(
             path=fnam,
         ).visit(ast)
     except SyntaxError as e:
-        # alias to please mypyc
-        is_py38_or_earlier = sys.version_info < (3, 9)
-        if is_py38_or_earlier and e.filename == "<fstring>":
-            # In Python 3.8 and earlier, syntax errors in f-strings have lineno relative to the
-            # start of the f-string. This would be misleading, as mypy will report the error as the
-            # lineno within the file.
-            e.lineno = None
         message = e.msg
         if feature_version > sys.version_info.minor and message.startswith("invalid syntax"):
             python_version_str = f"{options.python_version[0]}.{options.python_version[1]}"
@@ -2070,40 +2062,15 @@ def visit_Index(self, n: ast3.Index) -> Type:
     def visit_Slice(self, n: ast3.Slice) -> Type:
         return self.invalid_type(n, note="did you mean to use ',' instead of ':' ?")
 
-    # Subscript(expr value, slice slice, expr_context ctx)  # Python 3.8 and before
     # Subscript(expr value, expr slice, expr_context ctx)  # Python 3.9 and later
     def visit_Subscript(self, n: ast3.Subscript) -> Type:
-        if sys.version_info >= (3, 9):  # Really 3.9a5 or later
-            sliceval: Any = n.slice
-        # Python 3.8 or earlier use a different AST structure for subscripts
-        elif isinstance(n.slice, ast3.Index):
-            sliceval: Any = n.slice.value
-        elif isinstance(n.slice, ast3.Slice):
-            sliceval = copy.deepcopy(n.slice)  # so we don't mutate passed AST
-            if getattr(sliceval, "col_offset", None) is None:
-                # Fix column information so that we get Python 3.9+ message order
-                sliceval.col_offset = sliceval.lower.col_offset
-        else:
-            assert isinstance(n.slice, ast3.ExtSlice)
-            dims = cast(List[ast3.expr], copy.deepcopy(n.slice.dims))
-            for s in dims:
-                # These fields don't actually have a col_offset attribute but we add
-                # it manually.
-                if getattr(s, "col_offset", None) is None:
-                    if isinstance(s, ast3.Index):
-                        s.col_offset = s.value.col_offset
-                    elif isinstance(s, ast3.Slice):
-                        assert s.lower is not None
-                        s.col_offset = s.lower.col_offset
-            sliceval = ast3.Tuple(dims, n.ctx)
-
         empty_tuple_index = False
-        if isinstance(sliceval, ast3.Tuple):
-            params = self.translate_expr_list(sliceval.elts)
-            if len(sliceval.elts) == 0:
+        if isinstance(n.slice, ast3.Tuple):
+            params = self.translate_expr_list(n.slice.elts)
+            if len(n.slice.elts) == 0:
                 empty_tuple_index = True
         else:
-            params = [self.visit(sliceval)]
+            params = [self.visit(n.slice)]
 
         value = self.visit(n.value)
         if isinstance(value, UnboundType) and not value.args:

mypy/main.py

@@ -11,7 +11,7 @@
 from collections.abc import Sequence
 from gettext import gettext
 from io import TextIOWrapper
-from typing import IO, Any, Final, NoReturn, TextIO
+from typing import IO, Any, Final, NoReturn, Protocol, TextIO
 
 from mypy import build, defaults, state, util
 from mypy.config_parser import (
@@ -36,6 +36,11 @@
 from mypy.split_namespace import SplitNamespace
 from mypy.version import __version__
 
+
+class _SupportsWrite(Protocol):
+    def write(self, s: str, /) -> object: ...
+
+
 orig_stat: Final = os.stat
 MEM_PROFILE: Final = False  # If True, dump memory profile
 
@@ -373,17 +378,17 @@ def __init__(self, *args: Any, **kwargs: Any) -> None:
     # =====================
     # Help-printing methods
     # =====================
-    def print_usage(self, file: IO[str] | None = None) -> None:
+    def print_usage(self, file: _SupportsWrite | None = None) -> None:
         if file is None:
             file = self.stdout
         self._print_message(self.format_usage(), file)
 
-    def print_help(self, file: IO[str] | None = None) -> None:
+    def print_help(self, file: _SupportsWrite | None = None) -> None:
         if file is None:
             file = self.stdout
         self._print_message(self.format_help(), file)
 
-    def _print_message(self, message: str, file: IO[str] | None = None) -> None:
+    def _print_message(self, message: str, file: _SupportsWrite | None = None) -> None:
         if message:
             if file is None:
                 file = self.stderr

mypy/messages.py

@@ -2701,7 +2701,7 @@ def format_literal_value(typ: LiteralType) -> str:
         if func.is_type_obj():
             # The type of a type object type can be derived from the
             # return type (this always works).
-            return format(TypeType.make_normalized(erase_type(func.items[0].ret_type)))
+            return format(TypeType.make_normalized(func.items[0].ret_type))
         elif isinstance(func, CallableType):
             if func.type_guard is not None:
                 return_type = f"TypeGuard[{format(func.type_guard)}]"

mypy/mixedtraverser.py

@@ -30,14 +30,14 @@ def __init__(self) -> None:
 
     # Symbol nodes
 
-    def visit_var(self, var: Var) -> None:
+    def visit_var(self, var: Var, /) -> None:
         self.visit_optional_type(var.type)
 
-    def visit_func(self, o: FuncItem) -> None:
+    def visit_func(self, o: FuncItem, /) -> None:
         super().visit_func(o)
         self.visit_optional_type(o.type)
 
-    def visit_class_def(self, o: ClassDef) -> None:
+    def visit_class_def(self, o: ClassDef, /) -> None:
         # TODO: Should we visit generated methods/variables as well, either here or in
         #       TraverserVisitor?
         super().visit_class_def(o)
@@ -46,67 +46,67 @@ def visit_class_def(self, o: ClassDef) -> None:
             for base in info.bases:
                 base.accept(self)
 
-    def visit_type_alias_expr(self, o: TypeAliasExpr) -> None:
+    def visit_type_alias_expr(self, o: TypeAliasExpr, /) -> None:
         super().visit_type_alias_expr(o)
         self.in_type_alias_expr = True
         o.node.target.accept(self)
         self.in_type_alias_expr = False
 
-    def visit_type_var_expr(self, o: TypeVarExpr) -> None:
+    def visit_type_var_expr(self, o: TypeVarExpr, /) -> None:
         super().visit_type_var_expr(o)
         o.upper_bound.accept(self)
         for value in o.values:
             value.accept(self)
 
-    def visit_typeddict_expr(self, o: TypedDictExpr) -> None:
+    def visit_typeddict_expr(self, o: TypedDictExpr, /) -> None:
         super().visit_typeddict_expr(o)
         self.visit_optional_type(o.info.typeddict_type)
 
-    def visit_namedtuple_expr(self, o: NamedTupleExpr) -> None:
+    def visit_namedtuple_expr(self, o: NamedTupleExpr, /) -> None:
         super().visit_namedtuple_expr(o)
         assert o.info.tuple_type
         o.info.tuple_type.accept(self)
 
-    def visit__promote_expr(self, o: PromoteExpr) -> None:
+    def visit__promote_expr(self, o: PromoteExpr, /) -> None:
         super().visit__promote_expr(o)
         o.type.accept(self)
 
-    def visit_newtype_expr(self, o: NewTypeExpr) -> None:
+    def visit_newtype_expr(self, o: NewTypeExpr, /) -> None:
         super().visit_newtype_expr(o)
         self.visit_optional_type(o.old_type)
 
     # Statements
 
-    def visit_assignment_stmt(self, o: AssignmentStmt) -> None:
+    def visit_assignment_stmt(self, o: AssignmentStmt, /) -> None:
         super().visit_assignment_stmt(o)
         self.visit_optional_type(o.type)
 
-    def visit_for_stmt(self, o: ForStmt) -> None:
+    def visit_for_stmt(self, o: ForStmt, /) -> None:
         super().visit_for_stmt(o)
         self.visit_optional_type(o.index_type)
 
-    def visit_with_stmt(self, o: WithStmt) -> None:
+    def visit_with_stmt(self, o: WithStmt, /) -> None:
         super().visit_with_stmt(o)
         for typ in o.analyzed_types:
             typ.accept(self)
 
     # Expressions
 
-    def visit_cast_expr(self, o: CastExpr) -> None:
+    def visit_cast_expr(self, o: CastExpr, /) -> None:
         super().visit_cast_expr(o)
         o.type.accept(self)
 
-    def visit_assert_type_expr(self, o: AssertTypeExpr) -> None:
+    def visit_assert_type_expr(self, o: AssertTypeExpr, /) -> None:
         super().visit_assert_type_expr(o)
         o.type.accept(self)
 
-    def visit_type_application(self, o: TypeApplication) -> None:
+    def visit_type_application(self, o: TypeApplication, /) -> None:
         super().visit_type_application(o)
         for t in o.types:
             t.accept(self)
 
     # Helpers
 
-    def visit_optional_type(self, t: Type | None) -> None:
+    def visit_optional_type(self, t: Type | None, /) -> None:
         if t:
             t.accept(self)

mypy/modulefinder.py

@@ -751,7 +751,7 @@ def default_lib_path(
     return path
 
 
-@functools.lru_cache(maxsize=None)
+@functools.cache
 def get_search_dirs(python_executable: str | None) -> tuple[list[str], list[str]]:
     """Find package directories for given python. Guaranteed to return absolute paths.
 

mypy/pyinfo.py

@@ -2,9 +2,9 @@
 
 """Utilities to find the site and prefix information of a Python executable.
 
-This file MUST remain compatible with all Python 3.8+ versions. Since we cannot make any
+This file MUST remain compatible with all Python 3.9+ versions. Since we cannot make any
 assumptions about the Python being executed, this module should not use *any* dependencies outside
-of the standard library found in Python 3.8. This file is run each mypy run, so it should be kept
+of the standard library found in Python 3.9. This file is run each mypy run, so it should be kept
 as fast as possible.
 """
 import sys