config: remove _config_source_hint, use extra_info instead

Let's use a single mechanism. The error is now shown in its own line but
that's fine.

Author: bluetech

src/_pytest/config/__init__.py

@@ -1307,13 +1307,13 @@ def _unconfigure_python_path(self) -> None:
 
     def _validate_args(self, args: list[str], via: str) -> list[str]:
         """Validate known args."""
-        self._parser._config_source_hint = via
+        self._parser.extra_info["config source"] = via
         try:
             self._parser.parse_known_and_unknown_args(
                 args, namespace=copy.copy(self.option)
             )
         finally:
-            self._parser._config_source_hint = None
+            self._parser.extra_info.pop("config source", None)
 
         return args
 

src/_pytest/config/argparsing.py

@@ -53,7 +53,6 @@ def __init__(
         # Maps alias -> canonical name.
         self._ini_aliases: dict[str, str] = {}
         self.extra_info: dict[str, Any] = {}
-        self._config_source_hint: str | None = None
 
     def processoption(self, option: Argument) -> None:
         if self._processopt:
@@ -446,8 +445,6 @@ def __init__(
     def error(self, message: str) -> NoReturn:
         """Transform argparse error message into UsageError."""
         msg = f"{self.prog}: error: {message}"
-        if self._parser._config_source_hint is not None:
-            msg = f"{msg} ({self._parser._config_source_hint})"
         if self.extra_info:
             msg += "\n" + "\n".join(
                 f"  {k}: {v}" for k, v in sorted(self.extra_info.items())

testing/test_config.py

@@ -2290,9 +2290,10 @@ def test_addopts_from_env_not_concatenated(
         with pytest.raises(UsageError) as excinfo:
             config._preparse(["cache_dir=ignored"], addopts=True)
         assert (
-            "error: argument -o/--override-ini: expected one argument (via PYTEST_ADDOPTS)"
+            "error: argument -o/--override-ini: expected one argument"
             in excinfo.value.args[0]
         )
+        assert "via PYTEST_ADDOPTS" in excinfo.value.args[0]
 
     def test_addopts_from_ini_not_concatenated(self, pytester: Pytester) -> None:
         """`addopts` from configuration should not take values from normal args (#4265)."""
@@ -2303,10 +2304,11 @@ def test_addopts_from_ini_not_concatenated(self, pytester: Pytester) -> None:
         """
         )
         result = pytester.runpytest("cache_dir=ignored")
+        config = pytester._request.config
         result.stderr.fnmatch_lines(
             [
-                f"{pytester._request.config._parser.optparser.prog}: error: "
-                f"argument -o/--override-ini: expected one argument (via addopts config)"
+                f"{config._parser.optparser.prog}: error: argument -o/--override-ini: expected one argument",
+                "  config source: via addopts config",
             ]
         )
         assert result.ret == _pytest.config.ExitCode.USAGE_ERROR