config: remove PytestArgumentParser in favor of exit_on_error=False

Since Python 3.9 argparse supports `exit_on_error` parameter that makes
it just propagate an exception instead of calling `error`:
https://docs.python.org/3/library/argparse.html#exit-on-error

We can use it to get rid of `PytestArgumentParser`, less cognitive
overhead.

Author: bluetech

src/_pytest/config/argparsing.py

@@ -10,7 +10,6 @@
 from typing import Any
 from typing import final
 from typing import Literal
-from typing import NoReturn
 
 from .exceptions import UsageError
 import _pytest._io
@@ -42,7 +41,14 @@ def __init__(
 
         self._processopt = processopt
         self.extra_info: dict[str, Any] = {}
-        self.optparser = PytestArgumentParser(usage, self.extra_info)
+        self.optparser = argparse.ArgumentParser(
+            usage=usage,
+            add_help=False,
+            exit_on_error=False,
+            formatter_class=DropShorterLongHelpFormatter,
+            allow_abbrev=False,
+            fromfile_prefix_chars="@",
+        )
         anonymous_arggroup = self.optparser.add_argument_group("Custom options")
         self._anonymous = OptionGroup(
             anonymous_arggroup, "_anonymous", self, _ispytest=True
@@ -117,6 +123,14 @@ def addoption(self, *opts: str, **attrs: Any) -> None:
         """
         self._anonymous.addoption(*opts, **attrs)
 
+    def _format_usage_error(self, e: argparse.ArgumentError) -> str:
+        msg = f"{self.prog}: error: {e}"
+        if self.extra_info:
+            msg += "\n" + "\n".join(
+                f"  {k}: {v}" for k, v in sorted(self.extra_info.items())
+            )
+        return self.optparser.format_usage() + msg
+
     def parse(
         self,
         args: Sequence[str | os.PathLike[str]],
@@ -135,9 +149,11 @@ def parse(
         strargs = [os.fspath(x) for x in args]
         if namespace is None:
             namespace = argparse.Namespace()
+        namespace._raise_print_help = True
         try:
-            namespace._raise_print_help = True
             return self.optparser.parse_intermixed_args(strargs, namespace=namespace)
+        except argparse.ArgumentError as e:
+            raise UsageError(self._format_usage_error(e)) from None
         finally:
             del namespace._raise_print_help
 
@@ -165,17 +181,20 @@ def parse_known_and_unknown_args(
             arguments, and a list of unknown flag arguments.
         """
         strargs = [os.fspath(x) for x in args]
-        if sys.version_info < (3, 12):
-            # Older argparse have a bugged parse_known_intermixed_args.
-            namespace, unknown = self.optparser.parse_known_args(strargs, namespace)
-            assert namespace is not None
-            file_or_dir = getattr(namespace, FILE_OR_DIR)
-            unknown_flags: list[str] = []
-            for arg in unknown:
-                (unknown_flags if arg.startswith("-") else file_or_dir).append(arg)
-            return namespace, unknown_flags
-        else:
-            return self.optparser.parse_known_intermixed_args(strargs, namespace)
+        try:
+            if sys.version_info < (3, 12):
+                # Older argparse have a bugged parse_known_intermixed_args.
+                namespace, unknown = self.optparser.parse_known_args(strargs, namespace)
+                assert namespace is not None
+                file_or_dir = getattr(namespace, FILE_OR_DIR)
+                unknown_flags: list[str] = []
+                for arg in unknown:
+                    (unknown_flags if arg.startswith("-") else file_or_dir).append(arg)
+                return namespace, unknown_flags
+            else:
+                return self.optparser.parse_known_intermixed_args(strargs, namespace)
+        except argparse.ArgumentError as e:
+            raise UsageError(self._format_usage_error(e)) from None
 
     def addini(
         self,
@@ -375,33 +394,6 @@ def _addoption_inner(
             self.parser.processoption(option)
 
 
-class PytestArgumentParser(argparse.ArgumentParser):
-    def __init__(
-        self,
-        usage: str | None,
-        extra_info: dict[str, str],
-    ) -> None:
-        super().__init__(
-            usage=usage,
-            add_help=False,
-            formatter_class=DropShorterLongHelpFormatter,
-            allow_abbrev=False,
-            fromfile_prefix_chars="@",
-        )
-        # extra_info is a dict of (param -> value) to display if there's
-        # an usage error to provide more contextual information to the user.
-        self.extra_info = extra_info
-
-    def error(self, message: str) -> NoReturn:
-        """Transform argparse error message into UsageError."""
-        msg = f"{self.prog}: error: {message}"
-        if self.extra_info:
-            msg += "\n" + "\n".join(
-                f"  {k}: {v}" for k, v in sorted(self.extra_info.items())
-            )
-        raise UsageError(self.format_usage() + msg)
-
-
 class DropShorterLongHelpFormatter(argparse.HelpFormatter):
     """Shorten help for long options that differ only in extra hyphens.