Update more

python · JukkaL · Apr 22, 2026 · Apr 20, 2026 · Apr 20, 2026 · Apr 20, 2026
commit 1c4a3ffbf95bff85593fd9ed6e200f3d45a31e27
diff --git a/mypy/binder.py b/mypy/binder.py
@@ -199,7 +199,7 @@ def __init__(self, options: Options) -> None:
 
         # If True, initial assignment to a simple variable (e.g. "x", but not "x.y")
         # is added to the binder. This allows more precise narrowing and more
-        # flexible inference of variable types (--allow-redefinition-new).
+        # flexible inference of variable types (--allow-redefinition).
         self.bind_all = options.allow_redefinition
 
         # This tracks any externally visible changes in binder to invalidate
@@ -339,7 +339,7 @@ def update_from_options(self, frames: list[Frame]) -> bool:
                 continue
 
             # Remove exact duplicates to save pointless work later, this is
-            # a micro-optimization for --allow-redefinition-new.
+            # a micro-optimization for --allow-redefinition.
             seen_types = set()
             resulting_types = []
             for rv in resulting_values:

diff --git a/mypy/checker.py b/mypy/checker.py
@@ -4607,7 +4607,7 @@ def infer_partial_type(self, name: Var, lvalue: Lvalue, init_type: Type) -> bool
         if isinstance(init_type, NoneType) and (
             isinstance(lvalue, MemberExpr) or not self.options.allow_redefinition
         ):
-            # When using --allow-redefinition-new, None types aren't special
+            # When using --allow-redefinition, None types aren't special
             # when inferring simple variable types.
             partial_type = PartialType(None, name)
         elif isinstance(init_type, Instance):
@@ -4855,7 +4855,7 @@ def check_simple_assignment(
                 get_proper_type(lvalue_type), AnyType
             )
 
-            # If redefinitions are allowed (i.e. we have --allow-redefinition-new
+            # If redefinitions are allowed (i.e. we have --allow-redefinition
             # and a variable without annotation) or if a variable has union type we
             # try inferring r.h.s. twice with a fallback type context. The only exception
             # is TypedDicts, they are often useless without context.
@@ -5025,7 +5025,7 @@ def replace_partial_type(
         self.binder.version += 1
         del partial_types[var]
         if self.options.allow_redefinition:
-            # When using --allow-redefinition-new, binder tracks all types of
+            # When using --allow-redefinition, binder tracks all types of
             # simple variables.
             n = NameExpr(var.name)
             n.node = var

diff --git a/mypy/config_parser.py b/mypy/config_parser.py
@@ -507,9 +507,9 @@ def parse_section(
         # Here we use `key` for original config section key, and `options_key` for
         # the corresponding Options attribute.
         options_key = key
-        # Match aliasing for command line flag.
-        if key.endswith("allow_redefinition"):
-            options_key += "_old"
+        # Match aliasing for deprecated config option name.
+        if options_key == "allow_redefinition_new":
+            options_key = "allow_redefinition"
         if key in config_types:
             ct = config_types[key]
         elif key in invalid_options:

diff --git a/mypy/main.py b/mypy/main.py
@@ -105,14 +105,14 @@ def main(
 
     if options.allow_redefinition and not options.local_partial_types:
         fail(
-            "error: --local-partial-types must be enabled if using --allow-redefinition-new",
+            "error: --local-partial-types must be enabled if using --allow-redefinition",
             stderr,
             options,
         )
 
     if options.allow_redefinition and options.allow_redefinition_old:
         fail(
-            "--allow-redefinition-old and --allow-redefinition-new should not be used together",
+            "--allow-redefinition-old and --allow-redefinition should not be used together",
             stderr,
             options,
         )
@@ -888,9 +888,8 @@ def add_invertible_flag(
         "--allow-redefinition",
         default=False,
         strict_flag=False,
-        help="Alias to --allow-redefinition-old; will point to --allow-redefinition-new in v2.0",
+        help="Allow flexible variable redefinition with a new type",
         group=strictness_group,
-        dest="allow_redefinition_old",
     )
 
     add_invertible_flag(
@@ -905,8 +904,9 @@ def add_invertible_flag(
         "--allow-redefinition-new",
         default=False,
         strict_flag=False,
-        help="Allow more flexible variable redefinition semantics",
+        help="Deprecated alias for --allow-redefinition",
         group=strictness_group,
+        dest="allow_redefinition",
     )
 
     add_invertible_flag(

diff --git a/mypy/nativeparse.py b/mypy/nativeparse.py
@@ -1,4 +1,4 @@
-# mypy: allow-redefinition-new, local-partial-types
+# mypy: allow-redefinition, local-partial-types
 """Python parser that directly constructs a native AST (when compiled).
 
 Use a Rust extension to generate a serialized AST, and deserialize the AST directly

diff --git a/mypy/semanal.py b/mypy/semanal.py
@@ -712,16 +712,15 @@ def refresh_top_level(self, file_node: MypyFile) -> None:
             n.column = 0
             n.end_line = 1
             n.end_column = 0
-            self.fail("--local-partial-types must be enabled if using --allow-redefinition-new", n)
+            self.fail("--local-partial-types must be enabled if using --allow-redefinition", n)
         if self.options.allow_redefinition and self.options.allow_redefinition_old:
             n = TempNode(AnyType(TypeOfAny.special_form))
             n.line = 1
             n.column = 0
             n.end_line = 1
             n.end_column = 0
             self.fail(
-                "--allow-redefinition-old and --allow-redefinition-new"
-                " should not be used together",
+                "--allow-redefinition-old and --allow-redefinition should not be used together",
                 n,
             )
         self.recurse_into_functions = False
@@ -4495,7 +4494,7 @@ def analyze_name_lvalue(
                 if self.is_func_scope():
                     if unmangle(name) == "_" and not self.options.allow_redefinition:
                         # Special case for assignment to local named '_': always infer 'Any'.
-                        # This isn't needed with --allow-redefinition-new, since arbitrary
+                        # This isn't needed with --allow-redefinition, since arbitrary
                         # types can be assigned to '_' anyway.
                         typ = AnyType(TypeOfAny.special_form)
                         self.store_declared_types(lvalue, typ)