config: deprecate config.inicfg

As a private attribute, we broke it in pytest 9.0.0, but since it's not
using a `_` prefix and has some external usage, let's keep it working
until pytest 10 and deprecate it instead.

Fix #13946.

Author: bluetech

changelog/13946.deprecation.rst

@@ -0,0 +1,4 @@
+The private ``config.inicfg`` attribute is now deprecated.
+Use :meth:`config.getini() <pytest.Config.getini>` to access configuration values instead.
+
+See :ref:`config-inicfg` for more details.

doc/en/deprecations.rst

@@ -15,6 +15,40 @@ Below is a complete list of all pytest features which are considered deprecated.
 :class:`~pytest.PytestWarning` or subclasses, which can be filtered using :ref:`standard warning filters <warnings>`.
 
 
+.. _config-inicfg:
+
+``config.inicfg``
+~~~~~~~~~~~~~~~~~
+
+.. deprecated:: 9.0
+
+The private ``config.inicfg`` attribute is deprecated.
+Use :meth:`config.getini() <pytest.Config.getini>` to access configuration values instead.
+
+**Reading configuration values:**
+
+Instead of accessing ``config.inicfg`` directly, use :meth:`config.getini() <pytest.Config.getini>`:
+
+.. code-block:: python
+
+    # Deprecated
+    value = config.inicfg["some_option"]
+
+    # Use this instead
+    value = config.getini("some_option")
+
+**Setting configuration values:**
+
+Setting or deleting configuration values after initialization is not supported.
+If you need to override configuration values, use the ``-o`` command line option:
+
+.. code-block:: bash
+
+    pytest -o some_option=value
+
+or set them in your configuration file instead.
+
+
 .. _parametrize-iterators:
 
 Non-Collection iterables in ``@pytest.mark.parametrize``

src/_pytest/config/__init__.py

@@ -11,6 +11,7 @@
 from collections.abc import Iterable
 from collections.abc import Iterator
 from collections.abc import Mapping
+from collections.abc import MutableMapping
 from collections.abc import Sequence
 import contextlib
 import copy
@@ -48,6 +49,8 @@
 from .compat import PathAwareHookProxy
 from .exceptions import PrintHelp as PrintHelp
 from .exceptions import UsageError as UsageError
+from .findpaths import ConfigDict
+from .findpaths import ConfigValue
 from .findpaths import determine_setup
 from _pytest import __version__
 import _pytest._code
@@ -56,6 +59,7 @@
 from _pytest._code.code import TracebackStyle
 from _pytest._io import TerminalWriter
 from _pytest.compat import assert_never
+from _pytest.compat import deprecated
 from _pytest.compat import NOTSET
 from _pytest.config.argparsing import Argument
 from _pytest.config.argparsing import FILE_OR_DIR
@@ -979,6 +983,30 @@ def _iter_rewritable_modules(package_files: Iterable[str]) -> Iterator[str]:
             yield from _iter_rewritable_modules(new_package_files)
 
 
+class _DeprecatedInicfgProxy(MutableMapping[str, Any]):
+    """Compatibility proxy for the deprecated Config.inicfg."""
+
+    __slots__ = ("_config",)
+
+    def __init__(self, config: Config) -> None:
+        self._config = config
+
+    def __getitem__(self, key: str) -> Any:
+        return self._config._inicfg[key].value
+
+    def __setitem__(self, key: str, value: Any) -> None:
+        self._config._inicfg[key] = ConfigValue(value, origin="override", mode="toml")
+
+    def __delitem__(self, key: str) -> None:
+        del self._config._inicfg[key]
+
+    def __iter__(self) -> Iterator[str]:
+        return iter(self._config._inicfg)
+
+    def __len__(self) -> int:
+        return len(self._config._inicfg)
+
+
 @final
 class Config:
     """Access to configuration values, pluginmanager and plugin hooks.
@@ -1089,6 +1117,7 @@ def __init__(
         self.trace = self.pluginmanager.trace.root.get("config")
         self.hook: pluggy.HookRelay = PathAwareHookProxy(self.pluginmanager.hook)  # type: ignore[assignment]
         self._inicache: dict[str, Any] = {}
+        self._inicfg: ConfigDict = {}
         self._cleanup_stack = contextlib.ExitStack()
         self.pluginmanager.register(self, "pytestconfig")
         self._configured = False
@@ -1098,6 +1127,24 @@ def __init__(
         self.args_source = Config.ArgsSource.ARGS
         self.args: list[str] = []
 
+    if TYPE_CHECKING:
+
+        @deprecated(
+            "config.inicfg is deprecated, use config.getini() to access configuration values instead.",
+        )
+        @property
+        def inicfg(self) -> _DeprecatedInicfgProxy:
+            raise NotImplementedError()
+    else:
+
+        @property
+        def inicfg(self) -> _DeprecatedInicfgProxy:
+            warnings.warn(
+                _pytest.deprecated.CONFIG_INICFG,
+                stacklevel=2,
+            )
+            return _DeprecatedInicfgProxy(self)
+
     @property
     def rootpath(self) -> pathlib.Path:
         """The path to the :ref:`rootdir <rootdir>`.
@@ -1428,7 +1475,7 @@ def _warn_or_fail_if_strict(self, message: str) -> None:
 
     def _get_unknown_ini_keys(self) -> set[str]:
         known_keys = self._parser._inidict.keys() | self._parser._ini_aliases.keys()
-        return self.inicfg.keys() - known_keys
+        return self._inicfg.keys() - known_keys
 
     def parse(self, args: list[str], addopts: bool = True) -> None:
         # Parse given cmdline arguments into this config object.
@@ -1459,7 +1506,7 @@ def parse(self, args: list[str], addopts: bool = True) -> None:
         self._rootpath = rootpath
         self._inipath = inipath
         self._ignored_config_files = ignored_config_files
-        self.inicfg = inicfg
+        self._inicfg = inicfg
         self._parser.extra_info["rootdir"] = str(self.rootpath)
         self._parser.extra_info["inifile"] = str(self.inipath)
 
@@ -1636,14 +1683,14 @@ def _getini(self, name: str):
         except KeyError as e:
             raise ValueError(f"unknown configuration value: {name!r}") from e
 
-        # Collect all possible values (canonical name + aliases) from inicfg.
+        # Collect all possible values (canonical name + aliases) from _inicfg.
         # Each candidate is (ConfigValue, is_canonical).
         candidates = []
-        if canonical_name in self.inicfg:
-            candidates.append((self.inicfg[canonical_name], True))
+        if canonical_name in self._inicfg:
+            candidates.append((self._inicfg[canonical_name], True))
         for alias, target in self._parser._ini_aliases.items():
-            if target == canonical_name and alias in self.inicfg:
-                candidates.append((self.inicfg[alias], False))
+            if target == canonical_name and alias in self._inicfg:
+                candidates.append((self._inicfg[alias], False))
 
         if not candidates:
             return default

src/_pytest/deprecated.py

@@ -83,6 +83,11 @@
     "See https://docs.pytest.org/en/stable/deprecations.html#parametrize-iterators",
 )
 
+CONFIG_INICFG = PytestRemovedIn10Warning(
+    "config.inicfg is deprecated, use config.getini() to access configuration values instead.\n"
+    "See https://docs.pytest.org/en/stable/deprecations.html#config-inicfg"
+)
+
 # You want to make some `__init__` or function "private".
 #
 #   def my_private_function(some, args):

testing/test_config.py

@@ -30,6 +30,7 @@
 from _pytest.monkeypatch import MonkeyPatch
 from _pytest.pathlib import absolutepath
 from _pytest.pytester import Pytester
+from _pytest.warning_types import PytestDeprecationWarning
 import pytest
 
 
@@ -60,7 +61,7 @@ def test_getcfg_and_config(
         _, _, cfg, _ = locate_config(Path.cwd(), [sub])
         assert cfg["name"] == ConfigValue("value", origin="file", mode="ini")
         config = pytester.parseconfigure(str(sub))
-        assert config.inicfg["name"] == ConfigValue("value", origin="file", mode="ini")
+        assert config._inicfg["name"] == ConfigValue("value", origin="file", mode="ini")
 
     def test_setupcfg_uses_toolpytest_with_pytest(self, pytester: Pytester) -> None:
         p1 = pytester.makepyfile("def test(): pass")
@@ -1433,10 +1434,10 @@ def test_inifilename(self, tmp_path: Path) -> None:
 
         # this indicates this is the file used for getting configuration values
         assert config.inipath == inipath
-        assert config.inicfg.get("name") == ConfigValue(
+        assert config._inicfg.get("name") == ConfigValue(
             "value", origin="file", mode="ini"
         )
-        assert config.inicfg.get("should_not_be_set") is None
+        assert config._inicfg.get("should_not_be_set") is None
 
 
 def test_options_on_small_file_do_not_blow_up(pytester: Pytester) -> None:
@@ -2276,7 +2277,7 @@ def test_addopts_before_initini(
         monkeypatch.setenv("PYTEST_ADDOPTS", f"-o cache_dir={cache_dir}")
         config = _config_for_test
         config.parse([], addopts=True)
-        assert config.inicfg.get("cache_dir") == ConfigValue(
+        assert config._inicfg.get("cache_dir") == ConfigValue(
             cache_dir, origin="override", mode="ini"
         )
 
@@ -2317,7 +2318,7 @@ def test_override_ini_does_not_contain_paths(
         """Check that -o no longer swallows all options after it (#3103)"""
         config = _config_for_test
         config.parse(["-o", "cache_dir=/cache", "/some/test/path"])
-        assert config.inicfg.get("cache_dir") == ConfigValue(
+        assert config._inicfg.get("cache_dir") == ConfigValue(
             "/cache", origin="override", mode="ini"
         )
 
@@ -2998,3 +2999,48 @@ def pytest_addoption(parser):
 
         with pytest.raises(TypeError, match=r"expects a string.*got int"):
             config.getini("string_not_string")
+
+
+class TestInicfgDeprecation:
+    """Tests for the deprecation of config.inicfg."""
+
+    def test_inicfg_deprecated(self, pytester: Pytester) -> None:
+        """Test that accessing config.inicfg issues a deprecation warning."""
+        pytester.makeini(
+            """
+            [pytest]
+            minversion = 3.0
+            """
+        )
+        config = pytester.parseconfig()
+
+        with pytest.warns(
+            PytestDeprecationWarning, match=r"config\.inicfg is deprecated"
+        ):
+            inicfg = config.inicfg  # type: ignore[deprecated]
+
+        assert config.getini("minversion") == "3.0"
+        assert inicfg["minversion"] == "3.0"
+        assert inicfg.get("minversion") == "3.0"
+        del inicfg["minversion"]
+        inicfg["minversion"] = "4.0"
+        assert list(inicfg.keys()) == ["minversion"]
+        assert list(inicfg.items()) == [("minversion", "4.0")]
+        assert len(inicfg) == 1
+
+    def test_issue_13946_setting_bool_no_longer_crashes(
+        self, pytester: Pytester
+    ) -> None:
+        """Regression test for #13946 - setting inicfg doesn't cause a crash."""
+        pytester.makepyfile(
+            """
+            def pytest_configure(config):
+                config.inicfg["xfail_strict"] = True
+
+            def test():
+                pass
+            """
+        )
+
+        result = pytester.runpytest()
+        assert result.ret == 0