May 23, 2025 · May 23, 2025 · May 23, 2025 · May 27, 2025 · May 27, 2025 · May 27, 2025
diff --git a/mypy/config_parser.py b/mypy/config_parser.py
    import tomli as tomllib

 from collections.abc import Mapping, MutableMapping, Sequence
 from typing import Any, Callable, Final, TextIO, Union
 from typing import Any, Callable, Final, TextIO, Union, cast
 from typing_extensions import TypeAlias as _TypeAlias

 from mypy import defaults
    stdout: TextIO | None = None,
    stderr: TextIO | None = None,
 ) -> None:
    """Parse a config file into an Options object.
    """Parse a config file into an Options object, following config extend arguments.

    Errors are written to stderr but are not fatal.

    stdout = stdout or sys.stdout
    stderr = stderr or sys.stderr

    strict_found = False

    def set_strict(value: bool) -> None:
        nonlocal strict_found
        strict_found = value

    ret = _parse_and_extend_config_file(
        template=options,
        set_strict=set_strict,
        filename=filename,
        stdout=stdout,
        stderr=stderr,
        visited=set(),
    )

    if ret is None:
        return

    file_read, mypy_updates, mypy_report_dirs, module_updates = ret

    if strict_found:
        set_strict_flags()

    options.config_file = file_read

    for k, v in mypy_updates.items():
        setattr(options, k, v)

    options.report_dirs.update(mypy_report_dirs)

    for glob, updates in module_updates.items():
        options.per_module_options[glob] = updates


 def _merge_updates(existing: dict[str, object], new: dict[str, object]) -> None:
    existing["disable_error_code"] = list(
        set(
            cast(list[str], existing.get("disable_error_code", []))
            + cast(list[str], new.pop("disable_error_code", []))
        )
    )
    existing["enable_error_code"] = list(
        set(
            cast(list[str], existing.get("enable_error_code", []))
            + cast(list[str], new.pop("enable_error_code", []))
        )
    )
    existing.update(new)


 def _parse_and_extend_config_file(
    template: Options,
    set_strict: Callable[[bool], None],
    filename: str | None,
    stdout: TextIO,
    stderr: TextIO,
    visited: set[str],
 ) -> tuple[str, dict[str, object], dict[str, str], dict[str, dict[str, object]]] | None:
    ret = (
        _parse_individual_file(filename, stderr)
        if filename is not None
        else _find_config_file(stderr)
    )
    if ret is None:
        return
        return None
    parser, config_types, file_read = ret

    options.config_file = file_read
    os.environ["MYPY_CONFIG_FILE_DIR"] = os.path.dirname(os.path.abspath(file_read))
    abs_file_read = os.path.abspath(file_read)
    if abs_file_read in visited:
        print(f"Circular extend detected: {abs_file_read}", file=stderr)
        return None
    visited.add(abs_file_read)

    if len(visited) == 1:
        # set it only after the first config file is visited to allow for path variable expansions
        # when parsing below, so recursive calls for config extend references won't overwrite it
        os.environ["MYPY_CONFIG_FILE_DIR"] = os.path.dirname(abs_file_read)

    mypy_updates: dict[str, object] = {}
    mypy_report_dirs: dict[str, str] = {}
    module_updates: dict[str, dict[str, object]] = {}

    if "mypy" not in parser:
        if filename or os.path.basename(file_read) not in defaults.SHARED_CONFIG_NAMES:
            print(f"{file_read}: No [mypy] section in config file", file=stderr)
    else:
        section = parser["mypy"]

        extend = section.pop("extend", None)
        if extend:
            parse_ret = _parse_and_extend_config_file(
                template=template,
                set_strict=set_strict,
                # refer to extend relative to directory where we found current config
                filename=os.path.relpath(
                    os.path.normpath(
                        os.path.join(os.path.dirname(abs_file_read), expand_path(extend))
                    )
                ),
                stdout=stdout,
                stderr=stderr,
                visited=visited,
            )

            if parse_ret is None:
                print(f"{extend} is not a valid path to extend from {abs_file_read}", file=stderr)
            else:
                _, mypy_updates, mypy_report_dirs, module_updates = parse_ret

        prefix = f"{file_read}: [mypy]: "
        updates, report_dirs = parse_section(
            prefix,options, set_strict_flags, section, config_types, stderr
            prefix,template, set_strict, section, config_types, stderr
        )
 for k, v in updates.items():
    setattr(options, k, v)
 options.report_dirs.update(report_dirs)
 # extend and overwrite existing values with new ones
 _merge_updates(mypy_updates, updates)
 mypy_report_dirs.update(report_dirs)

    for name, section in parser.items():
        if name.startswith("mypy-"):
            prefix = get_prefix(file_read, name)
            updates, report_dirs = parse_section(
                prefix,options, set_strict_flags, section, config_types, stderr
                prefix,template, set_strict, section, config_types, stderr
            )
            if report_dirs:
                print(
                        file=stderr,
                    )
                else:
                    options.per_module_options[glob] = updates
                    # extend and overwrite existing values with new ones
                    _merge_updates(module_updates.setdefault(glob, {}), updates)

    return file_read, mypy_updates, mypy_report_dirs, module_updates


 def get_prefix(file_read: str, name: str) -> str:
 def parse_section(
    prefix: str,
    template: Options,
 set_strict_flags: Callable[[], None],
 set_strict: Callable[[bool], None],
    section: Mapping[str, Any],
    config_types: dict[str, Any],
    stderr: TextIO = sys.stderr,
            print(f"{prefix}{key}: {err}", file=stderr)
            continue
        if key == "strict":
            if v:
                set_strict_flags()
            set_strict(v)
            continue
        results[options_key] = v

        stderr = StringIO()
        strict_found = False

        defset_strict_flags() -> None:
        defset_strict(value: bool) -> None:
            nonlocal strict_found
            strict_found =True
            strict_found =value

        new_sections, reports = parse_section(
            "", template,set_strict_flags, parser["dummy"], ini_config_types, stderr=stderr
            "", template,set_strict, parser["dummy"], ini_config_types, stderr=stderr
        )
        errors.extend((lineno, x) for x in stderr.getvalue().strip().split("\n") if x)
        if reports:
diff --git a/mypy/test/test_config_parser.py b/mypy/test/test_config_parser.py
 from __future__ import annotations

 import contextlib
 import io
 import os
 import tempfile
 import unittest
 from collections.abc import Iterator
 from pathlib import Path

 from mypy.config_parser import _find_config_file
 from mypy.config_parser import _find_config_file, parse_config_file
 from mypy.defaults import CONFIG_NAMES, SHARED_CONFIG_NAMES
 from mypy.options import Options


 @contextlib.contextmanager
                result = _find_config_file()
                assert result is not None
                assert Path(result[2]).resolve() == parent_mypy.resolve()


 class ExtendConfigFileSuite(unittest.TestCase):

    def test_extend_success(self) -> None:
        with tempfile.TemporaryDirectory() as _tmpdir:
            tmpdir = Path(_tmpdir)
            with chdir(tmpdir):
                pyproject = tmpdir / "pyproject.toml"
                write_config(
                    pyproject,
                    "[tool.mypy]\n"
                    'extend = "./folder/mypy.ini"\n'
                    "strict = true\n"
                    "[[tool.mypy.overrides]]\n"
                    'module = "c"\n'
                    'enable_error_code = ["explicit-override"]\n'
                    "disallow_untyped_defs = true",
                )
                folder = tmpdir / "folder"
                folder.mkdir()
                write_config(
                    folder / "mypy.ini",
                    "[mypy]\n"
                    "strict = False\n"
                    "ignore_missing_imports_per_module = True\n"
                    "[mypy-c]\n"
                    "disallow_incomplete_defs = True",
                )

                options = Options()
                strict_option_set = False

                def set_strict_flags() -> None:
                    nonlocal strict_option_set
                    strict_option_set = True

                stdout = io.StringIO()
                stderr = io.StringIO()
                parse_config_file(options, set_strict_flags, None, stdout, stderr)

                assert strict_option_set is True
                assert options.ignore_missing_imports_per_module is True
                assert options.config_file == str(pyproject.name)
                if os.path.realpath(pyproject.parent).startswith("/private"):
                    # MacOS has some odd symlinks for tmp folder, resolve them to get the actual values
                    expected_path = os.path.realpath(pyproject.parent)
                else:
                    expected_path = str(pyproject.parent)
                assert os.environ["MYPY_CONFIG_FILE_DIR"] == expected_path

                assert options.per_module_options["c"] == {
                    "disable_error_code": [],
                    "enable_error_code": ["explicit-override"],
                    "disallow_untyped_defs": True,
                    "disallow_incomplete_defs": True,
                }

                assert stdout.getvalue() == ""
                assert stderr.getvalue() == ""

    def test_extend_cyclic(self) -> None:
        with tempfile.TemporaryDirectory() as _tmpdir:
            tmpdir = Path(_tmpdir)
            with chdir(tmpdir):
                pyproject = tmpdir / "pyproject.toml"
                write_config(pyproject, '[tool.mypy]\nextend = "./folder/mypy.ini"\n')

                folder = tmpdir / "folder"
                folder.mkdir()
                ini = folder / "mypy.ini"
                write_config(ini, "[mypy]\nextend = ../pyproject.toml\n")

                options = Options()

                stdout = io.StringIO()
                stderr = io.StringIO()
                parse_config_file(options, lambda: None, None, stdout, stderr)

                if os.path.realpath(pyproject).startswith("/private"):
                    # MacOS has some odd symlinks for tmp folder, resolve them to get the actual values
                    expected_pyproject = os.path.realpath(pyproject)
                    expected_ini = os.path.realpath(ini)
                else:
                    expected_pyproject = str(pyproject)
                    expected_ini = str(ini)

                assert stdout.getvalue() == ""
                assert stderr.getvalue() == (
                    f"Circular extend detected: {expected_pyproject}\n"
                    f"../pyproject.toml is not a valid path to extend from {expected_ini}\n"
                )

    def test_extend_strict_override(self) -> None:
        with tempfile.TemporaryDirectory() as _tmpdir:
            tmpdir = Path(_tmpdir)
            with chdir(tmpdir):
                pyproject = tmpdir / "pyproject.toml"
                write_config(
                    pyproject, '[tool.mypy]\nextend = "./folder/mypy.ini"\nstrict = True\n'
                )

                folder = tmpdir / "folder"
                folder.mkdir()
                ini = folder / "mypy.ini"
                write_config(ini, "[mypy]\nstrict = false\n")

                options = Options()

                stdout = io.StringIO()
                stderr = io.StringIO()

                strict_called = False

                def set_strict_flags() -> None:
                    nonlocal strict_called
                    strict_called = True

                parse_config_file(options, set_strict_flags, None, stdout, stderr)

                assert strict_called is False
Original file line number	Diff line number	Diff line change
Expand Up		@@ -16,7 +16,7 @@
		import tomli as tomllib

		from collections.abc import Mapping, MutableMapping, Sequence
		from typing import Any, Callable, Final, TextIO, Union
		from typing import Any, Callable, Final, TextIO, Union, cast
		from typing_extensions import TypeAlias as _TypeAlias

		from mypy import defaults
Expand DownExpand Up		@@ -292,7 +292,7 @@ def parse_config_file(
		stdout: TextIO \| None = None,
		stderr: TextIO \| None = None,
		) -> None:
		"""Parse a config file into an Options object.
		"""Parse a config file into an Options object, following config extend arguments.

		Errors are written to stderr but are not fatal.

Expand All		@@ -301,36 +301,128 @@ def parse_config_file(
		stdout = stdout or sys.stdout
		stderr = stderr or sys.stderr

		strict_found = False

		def set_strict(value: bool) -> None:
		nonlocal strict_found
		strict_found = value

		ret = _parse_and_extend_config_file(
		template=options,
		set_strict=set_strict,
		filename=filename,
		stdout=stdout,
		stderr=stderr,
		visited=set(),
		)

		if ret is None:
		return

		file_read, mypy_updates, mypy_report_dirs, module_updates = ret

		if strict_found:
		set_strict_flags()

		options.config_file = file_read

		for k, v in mypy_updates.items():
		setattr(options, k, v)

		options.report_dirs.update(mypy_report_dirs)

		for glob, updates in module_updates.items():
		options.per_module_options[glob] = updates


		def _merge_updates(existing: dict[str, object], new: dict[str, object]) -> None:
		existing["disable_error_code"] = list(
		set(
		cast(list[str], existing.get("disable_error_code", []))
		+ cast(list[str], new.pop("disable_error_code", []))
		)
		)
		existing["enable_error_code"] = list(
		set(
		cast(list[str], existing.get("enable_error_code", []))
		+ cast(list[str], new.pop("enable_error_code", []))
		)
		)
		existing.update(new)


		def _parse_and_extend_config_file(
		template: Options,
		set_strict: Callable[[bool], None],
		filename: str \| None,
		stdout: TextIO,
		stderr: TextIO,
		visited: set[str],
		) -> tuple[str, dict[str, object], dict[str, str], dict[str, dict[str, object]]] \| None:
		ret = (
		_parse_individual_file(filename, stderr)
		if filename is not None
		else _find_config_file(stderr)
		)
		if ret is None:
		return
		return None
		parser, config_types, file_read = ret

		options.config_file = file_read
		os.environ["MYPY_CONFIG_FILE_DIR"] = os.path.dirname(os.path.abspath(file_read))
		abs_file_read = os.path.abspath(file_read)
		if abs_file_read in visited:
		print(f"Circular extend detected: {abs_file_read}", file=stderr)
		return None
		visited.add(abs_file_read)

		if len(visited) == 1:
		# set it only after the first config file is visited to allow for path variable expansions
		# when parsing below, so recursive calls for config extend references won't overwrite it
		os.environ["MYPY_CONFIG_FILE_DIR"] = os.path.dirname(abs_file_read)

		mypy_updates: dict[str, object] = {}
		mypy_report_dirs: dict[str, str] = {}
		module_updates: dict[str, dict[str, object]] = {}

		if "mypy" not in parser:
		if filename or os.path.basename(file_read) not in defaults.SHARED_CONFIG_NAMES:
		print(f"{file_read}: No [mypy] section in config file", file=stderr)
		else:
		section = parser["mypy"]

		extend = section.pop("extend", None)
		if extend:
		parse_ret = _parse_and_extend_config_file(
		template=template,
		set_strict=set_strict,
		# refer to extend relative to directory where we found current config
		filename=os.path.relpath(
		os.path.normpath(
		os.path.join(os.path.dirname(abs_file_read), expand_path(extend))
		)
		),
		stdout=stdout,
		stderr=stderr,
		visited=visited,
		)

		if parse_ret is None:
		print(f"{extend} is not a valid path to extend from {abs_file_read}", file=stderr)
		else:
		_, mypy_updates, mypy_report_dirs, module_updates = parse_ret

		prefix = f"{file_read}: [mypy]: "
		updates, report_dirs = parse_section(
		prefix,options, set_strict_flags, section, config_types, stderr
		prefix,template, set_strict, section, config_types, stderr
		)
		for k, v in updates.items():
		setattr(options, k, v)
		options.report_dirs.update(report_dirs)
		# extend and overwrite existing values with new ones
		_merge_updates(mypy_updates, updates)
		mypy_report_dirs.update(report_dirs)

		for name, section in parser.items():
		if name.startswith("mypy-"):
		prefix = get_prefix(file_read, name)
		updates, report_dirs = parse_section(
		prefix,options, set_strict_flags, section, config_types, stderr
		prefix,template, set_strict, section, config_types, stderr
		)
		if report_dirs:
		print(
Expand DownExpand Up		@@ -367,7 +459,10 @@ def parse_config_file(
		file=stderr,
		)
		else:
		options.per_module_options[glob] = updates
		# extend and overwrite existing values with new ones
		_merge_updates(module_updates.setdefault(glob, {}), updates)

		return file_read, mypy_updates, mypy_report_dirs, module_updates


		def get_prefix(file_read: str, name: str) -> str:
Expand DownExpand Up		@@ -469,7 +564,7 @@ def destructure_overrides(toml_data: dict[str, Any]) -> dict[str, Any]:
		def parse_section(
		prefix: str,
		template: Options,
		set_strict_flags: Callable[[], None],
		set_strict: Callable[[bool], None],
		section: Mapping[str, Any],
		config_types: dict[str, Any],
		stderr: TextIO = sys.stderr,
Expand DownExpand Up		@@ -558,8 +653,7 @@ def parse_section(
		print(f"{prefix}{key}: {err}", file=stderr)
		continue
		if key == "strict":
		if v:
		set_strict_flags()
		set_strict(v)
		continue
		results[options_key] = v

Expand DownExpand Up		@@ -660,12 +754,12 @@ def parse_mypy_comments(
		stderr = StringIO()
		strict_found = False

		defset_strict_flags() -> None:
		defset_strict(value: bool) -> None:
		nonlocal strict_found
		strict_found =True
		strict_found =value

		new_sections, reports = parse_section(
		"", template,set_strict_flags, parser["dummy"], ini_config_types, stderr=stderr
		"", template,set_strict, parser["dummy"], ini_config_types, stderr=stderr
		)
		errors.extend((lineno, x) for x in stderr.getvalue().strip().split("\n") if x)
		if reports:
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -1,14 +1,16 @@
		from __future__ import annotations

		import contextlib
		import io
		import os
		import tempfile
		import unittest
		from collections.abc import Iterator
		from pathlib import Path

		from mypy.config_parser import _find_config_file
		from mypy.config_parser import _find_config_file, parse_config_file
		from mypy.defaults import CONFIG_NAMES, SHARED_CONFIG_NAMES
		from mypy.options import Options


		@contextlib.contextmanager
Expand DownExpand Up		@@ -128,3 +130,124 @@ def test_precedence_missing_section(self) -> None:
		result = _find_config_file()
		assert result is not None
		assert Path(result[2]).resolve() == parent_mypy.resolve()


		class ExtendConfigFileSuite(unittest.TestCase):

		def test_extend_success(self) -> None:
		with tempfile.TemporaryDirectory() as _tmpdir:
		tmpdir = Path(_tmpdir)
		with chdir(tmpdir):
		pyproject = tmpdir / "pyproject.toml"
		write_config(
		pyproject,
		"[tool.mypy]\n"
		'extend = "./folder/mypy.ini"\n'
		"strict = true\n"
		"[[tool.mypy.overrides]]\n"
		'module = "c"\n'
		'enable_error_code = ["explicit-override"]\n'
		"disallow_untyped_defs = true",
		)
		folder = tmpdir / "folder"
		folder.mkdir()
		write_config(
		folder / "mypy.ini",
		"[mypy]\n"
		"strict = False\n"
		"ignore_missing_imports_per_module = True\n"
		"[mypy-c]\n"
		"disallow_incomplete_defs = True",
		)

		options = Options()
		strict_option_set = False

		def set_strict_flags() -> None:
		nonlocal strict_option_set
		strict_option_set = True

		stdout = io.StringIO()
		stderr = io.StringIO()
		parse_config_file(options, set_strict_flags, None, stdout, stderr)

		assert strict_option_set is True
		assert options.ignore_missing_imports_per_module is True
		assert options.config_file == str(pyproject.name)
		if os.path.realpath(pyproject.parent).startswith("/private"):
		# MacOS has some odd symlinks for tmp folder, resolve them to get the actual values
		expected_path = os.path.realpath(pyproject.parent)
		else:
		expected_path = str(pyproject.parent)
		assert os.environ["MYPY_CONFIG_FILE_DIR"] == expected_path

		assert options.per_module_options["c"] == {
		"disable_error_code": [],
		"enable_error_code": ["explicit-override"],
		"disallow_untyped_defs": True,
		"disallow_incomplete_defs": True,
		}

		assert stdout.getvalue() == ""
		assert stderr.getvalue() == ""

		def test_extend_cyclic(self) -> None:
		with tempfile.TemporaryDirectory() as _tmpdir:
		tmpdir = Path(_tmpdir)
		with chdir(tmpdir):
		pyproject = tmpdir / "pyproject.toml"
		write_config(pyproject, '[tool.mypy]\nextend = "./folder/mypy.ini"\n')

		folder = tmpdir / "folder"
		folder.mkdir()
		ini = folder / "mypy.ini"
		write_config(ini, "[mypy]\nextend = ../pyproject.toml\n")

		options = Options()

		stdout = io.StringIO()
		stderr = io.StringIO()
		parse_config_file(options, lambda: None, None, stdout, stderr)

		if os.path.realpath(pyproject).startswith("/private"):
		# MacOS has some odd symlinks for tmp folder, resolve them to get the actual values
		expected_pyproject = os.path.realpath(pyproject)
		expected_ini = os.path.realpath(ini)
		else:
		expected_pyproject = str(pyproject)
		expected_ini = str(ini)

		assert stdout.getvalue() == ""
		assert stderr.getvalue() == (
		f"Circular extend detected: {expected_pyproject}\n"
		f"../pyproject.toml is not a valid path to extend from {expected_ini}\n"
		)

		def test_extend_strict_override(self) -> None:
		with tempfile.TemporaryDirectory() as _tmpdir:
		tmpdir = Path(_tmpdir)
		with chdir(tmpdir):
		pyproject = tmpdir / "pyproject.toml"
		write_config(
		pyproject, '[tool.mypy]\nextend = "./folder/mypy.ini"\nstrict = True\n'
		)

		folder = tmpdir / "folder"
		folder.mkdir()
		ini = folder / "mypy.ini"
		write_config(ini, "[mypy]\nstrict = false\n")

		options = Options()

		stdout = io.StringIO()
		stderr = io.StringIO()

		strict_called = False

		def set_strict_flags() -> None:
		nonlocal strict_called
		strict_called = True

		parse_config_file(options, set_strict_flags, None, stdout, stderr)

		assert strict_called is False