Merge branch 'master' into constant-fold-convert-format

BobTheBuidler · web-flow · commit 419d2ce97952 · 2025-10-04T01:21:01.000-04:00
diff --git a/docs/source/common_issues.rst b/docs/source/common_issues.rst
@@ -731,7 +731,7 @@ This example demonstrates both safe and unsafe overrides:
 
     class NarrowerReturn(A):
         # A more specific return type is fine
-        def test(self, t: Sequence[int]) -> List[str]:  # OK
+        def test(self, t: Sequence[int]) -> list[str]:  # OK
             ...
 
     class GeneralizedReturn(A):
@@ -746,7 +746,7 @@ not necessary:
 .. code-block:: python
 
     class NarrowerArgument(A):
-        def test(self, t: List[int]) -> Sequence[str]:  # type: ignore[override]
+        def test(self, t: list[int]) -> Sequence[str]:  # type: ignore[override]
             ...
 
 .. _unreachable:
diff --git a/mypy/build.py b/mypy/build.py
@@ -143,6 +143,10 @@ def __init__(self, manager: BuildManager, graph: Graph) -> None:
         self.errors: list[str] = []  # Filled in by build if desired
 
 
+def build_error(msg: str) -> NoReturn:
+    raise CompileError([f"mypy: error: {msg}"])
+
+
 def build(
     sources: list[BuildSource],
     options: Options,
@@ -241,6 +245,9 @@ def _build(
     errors = Errors(options, read_source=lambda path: read_py_file(path, cached_read))
     plugin, snapshot = load_plugins(options, errors, stdout, extra_plugins)
 
+    # Validate error codes after plugins are loaded.
+    options.process_error_codes(error_callback=build_error)
+
     # Add catch-all .gitignore to cache dir if we created it
     cache_dir_existed = os.path.isdir(options.cache_dir)
 
diff --git a/mypy/checker.py b/mypy/checker.py
@@ -1801,7 +1801,8 @@ def check___new___signature(self, fdef: FuncDef, typ: CallableType) -> None:
                 "but must return a subtype of",
             )
         elif not isinstance(
-            get_proper_type(bound_type.ret_type), (AnyType, Instance, TupleType, UninhabitedType)
+            get_proper_type(bound_type.ret_type),
+            (AnyType, Instance, TupleType, UninhabitedType, LiteralType),
         ):
             self.fail(
                 message_registry.NON_INSTANCE_NEW_TYPE.format(
diff --git a/mypy/checkmember.py b/mypy/checkmember.py
@@ -410,6 +410,8 @@ def analyze_type_callable_member_access(name: str, typ: FunctionLike, mx: Member
         ret_type = tuple_fallback(ret_type)
     if isinstance(ret_type, TypedDictType):
         ret_type = ret_type.fallback
+    if isinstance(ret_type, LiteralType):
+        ret_type = ret_type.fallback
     if isinstance(ret_type, Instance):
         if not mx.is_operator:
             # When Python sees an operator (eg `3 == 4`), it automatically translates that
diff --git a/mypy/config_parser.py b/mypy/config_parser.py
@@ -8,8 +8,6 @@
 import sys
 from io import StringIO
 
-from mypy.errorcodes import error_codes
-
 if sys.version_info >= (3, 11):
     import tomllib
 else:
@@ -87,15 +85,6 @@ def complain(x: object, additional_info: str = "") -> Never:
         complain(v)
 
 
-def validate_codes(codes: list[str]) -> list[str]:
-    invalid_codes = set(codes) - set(error_codes.keys())
-    if invalid_codes:
-        raise argparse.ArgumentTypeError(
-            f"Invalid error code(s): {', '.join(sorted(invalid_codes))}"
-        )
-    return codes
-
-
 def validate_package_allow_list(allow_list: list[str]) -> list[str]:
     for p in allow_list:
         msg = f"Invalid allow list entry: {p}"
@@ -209,8 +198,8 @@ def split_commas(value: str) -> list[str]:
         [p.strip() for p in split_commas(s)]
     ),
     "enable_incomplete_feature": lambda s: [p.strip() for p in split_commas(s)],
-    "disable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
-    "enable_error_code": lambda s: validate_codes([p.strip() for p in split_commas(s)]),
+    "disable_error_code": lambda s: [p.strip() for p in split_commas(s)],
+    "enable_error_code": lambda s: [p.strip() for p in split_commas(s)],
     "package_root": lambda s: [p.strip() for p in split_commas(s)],
     "cache_dir": expand_path,
     "python_executable": expand_path,
@@ -234,8 +223,8 @@ def split_commas(value: str) -> list[str]:
         "always_false": try_split,
         "untyped_calls_exclude": lambda s: validate_package_allow_list(try_split(s)),
         "enable_incomplete_feature": try_split,
-        "disable_error_code": lambda s: validate_codes(try_split(s)),
-        "enable_error_code": lambda s: validate_codes(try_split(s)),
+        "disable_error_code": lambda s: try_split(s),
+        "enable_error_code": lambda s: try_split(s),
         "package_root": try_split,
         "exclude": str_or_array_as_list,
         "packages": try_split,
diff --git a/mypy/main.py b/mypy/main.py
@@ -1066,11 +1066,7 @@ def add_invertible_flag(
     incremental_group.add_argument(
         "--fixed-format-cache",
         action="store_true",
-        help=(
-            "Use experimental fast and compact fixed format cache"
-            if compilation_status == "yes"
-            else argparse.SUPPRESS
-        ),
+        help="Use new fast and compact fixed format cache",
     )
     incremental_group.add_argument(
         "--skip-version-check",
@@ -1466,7 +1462,6 @@ def set_strict_flags() -> None:
     validate_package_allow_list(options.untyped_calls_exclude)
     validate_package_allow_list(options.deprecated_calls_exclude)
 
-    options.process_error_codes(error_callback=parser.error)
     options.process_incomplete_features(error_callback=parser.error, warning_callback=print)
 
     # Compute absolute path for custom typeshed (if present).
diff --git a/mypy/modulefinder.py b/mypy/modulefinder.py
@@ -796,7 +796,7 @@ def default_lib_path(
         custom_typeshed_dir = os.path.abspath(custom_typeshed_dir)
         typeshed_dir = os.path.join(custom_typeshed_dir, "stdlib")
         mypy_extensions_dir = os.path.join(custom_typeshed_dir, "stubs", "mypy-extensions")
-        mypy_native_dir = os.path.join(custom_typeshed_dir, "stubs", "mypy-native")
+        librt_dir = os.path.join(custom_typeshed_dir, "stubs", "librt")
         versions_file = os.path.join(typeshed_dir, "VERSIONS")
         if not os.path.isdir(typeshed_dir) or not os.path.isfile(versions_file):
             print(
@@ -812,13 +812,13 @@ def default_lib_path(
             data_dir = auto
         typeshed_dir = os.path.join(data_dir, "typeshed", "stdlib")
         mypy_extensions_dir = os.path.join(data_dir, "typeshed", "stubs", "mypy-extensions")
-        mypy_native_dir = os.path.join(data_dir, "typeshed", "stubs", "mypy-native")
+        librt_dir = os.path.join(data_dir, "typeshed", "stubs", "librt")
     path.append(typeshed_dir)
 
-    # Get mypy-extensions and mypy-native stubs from typeshed, since we treat them as
+    # Get mypy-extensions and librt stubs from typeshed, since we treat them as
     # "internal" libraries, similar to typing and typing-extensions.
     path.append(mypy_extensions_dir)
-    path.append(mypy_native_dir)
+    path.append(librt_dir)
 
     # Add fallback path that can be used if we have a broken installation.
     if sys.platform != "win32":
diff --git a/mypy/test/teststubtest.py b/mypy/test/teststubtest.py
@@ -12,6 +12,8 @@
 from collections.abc import Iterator
 from typing import Any, Callable
 
+from pytest import raises
+
 import mypy.stubtest
 from mypy import build, nodes
 from mypy.modulefinder import BuildSource
@@ -171,7 +173,12 @@ def build_helper(source: str) -> build.BuildResult:
 
 
 def run_stubtest_with_stderr(
-    stub: str, runtime: str, options: list[str], config_file: str | None = None
+    stub: str,
+    runtime: str,
+    options: list[str],
+    config_file: str | None = None,
+    output: io.StringIO | None = None,
+    outerr: io.StringIO | None = None,
 ) -> tuple[str, str]:
     with use_tmp_dir(TEST_MODULE_NAME) as tmp_dir:
         with open("builtins.pyi", "w") as f:
@@ -188,8 +195,8 @@ def run_stubtest_with_stderr(
             with open(f"{TEST_MODULE_NAME}_config.ini", "w") as f:
                 f.write(config_file)
             options = options + ["--mypy-config-file", f"{TEST_MODULE_NAME}_config.ini"]
-        output = io.StringIO()
-        outerr = io.StringIO()
+        output = io.StringIO() if output is None else output
+        outerr = io.StringIO() if outerr is None else outerr
         with contextlib.redirect_stdout(output), contextlib.redirect_stderr(outerr):
             test_stubs(parse_options([TEST_MODULE_NAME] + options), use_builtins_fixtures=True)
     filtered_output = remove_color_code(
@@ -2888,14 +2895,20 @@ def test_config_file_error_codes_invalid(self) -> None:
         runtime = "temp = 5\n"
         stub = "temp: int\n"
         config_file = "[mypy]\ndisable_error_code = not-a-valid-name\n"
-        output, outerr = run_stubtest_with_stderr(
-            stub=stub, runtime=runtime, options=[], config_file=config_file
-        )
-        assert output == "Success: no issues found in 1 module\n"
-        assert outerr == (
-            "test_module_config.ini: [mypy]: disable_error_code: "
-            "Invalid error code(s): not-a-valid-name\n"
-        )
+        output = io.StringIO()
+        outerr = io.StringIO()
+        with raises(SystemExit):
+            run_stubtest_with_stderr(
+                stub=stub,
+                runtime=runtime,
+                options=[],
+                config_file=config_file,
+                output=output,
+                outerr=outerr,
+            )
+
+        assert output.getvalue() == "error: Invalid error code(s): not-a-valid-name\n"
+        assert outerr.getvalue() == ""
 
     def test_config_file_wrong_incomplete_feature(self) -> None:
         runtime = "x = 1\n"
diff --git a/mypy/typeops.py b/mypy/typeops.py
@@ -319,7 +319,7 @@ def class_callable(
     default_ret_type = fill_typevars(info)
     explicit_type = init_ret_type if is_new else orig_self_type
     if (
-        isinstance(explicit_type, (Instance, TupleType, UninhabitedType))
+        isinstance(explicit_type, (Instance, TupleType, UninhabitedType, LiteralType))
         # We have to skip protocols, because it can be a subtype of a return type
         # by accident. Like `Hashable` is a subtype of `object`. See #11799
         and isinstance(default_ret_type, Instance)
diff --git a/mypy/types.py b/mypy/types.py
@@ -2278,6 +2278,8 @@ def type_object(self) -> mypy.nodes.TypeInfo:
             ret = ret.partial_fallback
         if isinstance(ret, TypedDictType):
             ret = ret.fallback
+        if isinstance(ret, LiteralType):
+            ret = ret.fallback
         assert isinstance(ret, Instance)
         return ret.type
 
diff --git a/mypy/typeshed/stubs/librt/METADATA.toml b/mypy/typeshed/stubs/librt/METADATA.toml
@@ -0,0 +1 @@
+version = "0.1.*"
diff --git a/mypy/typeshed/stubs/librt/native_internal.pyi b/mypy/typeshed/stubs/librt/native_internal.pyi
diff --git a/mypy/typeshed/stubs/mypy-native/METADATA.toml b/mypy/typeshed/stubs/mypy-native/METADATA.toml
diff --git a/mypyc/irbuild/builder.py b/mypyc/irbuild/builder.py
@@ -40,7 +40,6 @@
     TypeAlias,
     TypeInfo,
     TypeParam,
-    UnaryExpr,
     Var,
 )
 from mypy.types import (
@@ -106,6 +105,7 @@
     object_rprimitive,
     str_rprimitive,
 )
+from mypyc.irbuild.constant_fold import constant_fold_expr
 from mypyc.irbuild.context import FuncInfo, ImplicitClass
 from mypyc.irbuild.ll_builder import LowLevelIRBuilder
 from mypyc.irbuild.mapper import Mapper
@@ -965,12 +965,8 @@ def maybe_spill_assignable(self, value: Value) -> Register | AssignmentTarget:
         return reg
 
     def extract_int(self, e: Expression) -> int | None:
-        if isinstance(e, IntExpr):
-            return e.value
-        elif isinstance(e, UnaryExpr) and e.op == "-" and isinstance(e.expr, IntExpr):
-            return -e.expr.value
-        else:
-            return None
+        folded = constant_fold_expr(self, e)
+        return folded if isinstance(folded, int) else None
 
     def get_sequence_type(self, expr: Expression) -> RType:
         return self.get_sequence_type_from_type(self.types[expr])
diff --git a/mypyc/irbuild/constant_fold.py b/mypyc/irbuild/constant_fold.py
@@ -10,7 +10,7 @@
 
 from __future__ import annotations
 
-from typing import Final, Union
+from typing import TYPE_CHECKING, Final, Union
 
 from mypy.constant_fold import constant_fold_binary_op, constant_fold_unary_op
 from mypy.nodes import (
@@ -26,9 +26,11 @@
     UnaryExpr,
     Var,
 )
-from mypyc.irbuild.builder import IRBuilder
 from mypyc.irbuild.util import bytes_from_str
 
+if TYPE_CHECKING:
+    from mypyc.irbuild.builder import IRBuilder
+
 # All possible result types of constant folding
 ConstantValue = Union[int, float, complex, str, bytes]
 CONST_TYPES: Final = (int, float, complex, str, bytes)
diff --git a/mypyc/irbuild/specialize.py b/mypyc/irbuild/specialize.py
@@ -19,7 +19,6 @@
 from mypy.nodes import (
     ARG_NAMED,
     ARG_POS,
-    BytesExpr,
     CallExpr,
     DictExpr,
     Expression,
@@ -1057,9 +1056,9 @@ def translate_float(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Valu
 def translate_ord(builder: IRBuilder, expr: CallExpr, callee: RefExpr) -> Value | None:
     if len(expr.args) != 1 or expr.arg_kinds[0] != ARG_POS:
         return None
-    arg = expr.args[0]
-    if isinstance(arg, (StrExpr, BytesExpr)) and len(arg.value) == 1:
-        return Integer(ord(arg.value))
+    arg = constant_fold_expr(builder, expr.args[0])
+    if isinstance(arg, (str, bytes)) and len(arg) == 1:
+        return Integer(ord(arg))
     return None
 
 
diff --git a/pyproject.toml b/pyproject.toml
@@ -54,6 +54,7 @@ dependencies = [
   "mypy_extensions>=1.0.0",
   "pathspec>=0.9.0",
   "tomli>=1.1.0; python_version<'3.11'",
+  "librt>=0.1.0",
 ]
 dynamic = ["version"]
 
diff --git a/test-data/unit/check-classes.test b/test-data/unit/check-classes.test
@@ -472,6 +472,27 @@ class B(A):
     def __new__(cls) -> B:
         pass
 
+[case testOverride__new__WithLiteralReturnPassing]
+from typing import Literal
+
+class Falsy:
+    def __bool__(self) -> Literal[False]: pass
+
+reveal_type(bool(Falsy()))  # N: Revealed type is "Literal[False]"
+reveal_type(int())  # N: Revealed type is "Literal[0]"
+
+[builtins fixtures/literal__new__.pyi]
+[typing fixtures/typing-medium.pyi]
+
+[case testOverride__new__WithLiteralReturnFailing]
+from typing import Literal
+
+class Foo:
+    def __new__(cls) -> Literal[1]: pass # E: Incompatible return type for "__new__" (returns "Literal[1]", but must return a subtype of "Foo")
+
+[builtins fixtures/__new__.pyi]
+[typing fixtures/typing-medium.pyi]
+
 [case testOverride__new__AndCallObject]
 from typing import TypeVar, Generic
 
diff --git a/test-data/unit/check-plugin-error-codes.test b/test-data/unit/check-plugin-error-codes.test
@@ -0,0 +1,32 @@
+[case testCustomErrorCodeFromPluginIsTargetable]
+# flags: --config-file tmp/mypy.ini --show-error-codes
+
+def main() -> None:
+    return
+main() # E: Custom error  [custom]
+
+[file mypy.ini]
+\[mypy]
+plugins=<ROOT>/test-data/unit/plugins/custom_errorcode.py
+
+[case testCustomErrorCodeCanBeDisabled]
+# flags: --config-file tmp/mypy.ini --show-error-codes --disable-error-code=custom
+
+def main() -> None:
+    return
+main()  # no output expected when disabled
+
+[file mypy.ini]
+\[mypy]
+plugins=<ROOT>/test-data/unit/plugins/custom_errorcode.py
+
+[case testCustomErrorCodeCanBeReenabled]
+# flags: --config-file tmp/mypy.ini --show-error-codes --disable-error-code=custom --enable-error-code=custom
+
+def main() -> None:
+    return
+main() # E: Custom error  [custom]
+
+[file mypy.ini]
+\[mypy]
+plugins=<ROOT>/test-data/unit/plugins/custom_errorcode.py
diff --git a/test-data/unit/cmdline.test b/test-data/unit/cmdline.test
diff --git a/test-data/unit/fixtures/__new__.pyi b/test-data/unit/fixtures/__new__.pyi
diff --git a/test-data/unit/fixtures/literal__new__.pyi b/test-data/unit/fixtures/literal__new__.pyi
