Replace distutils.fancy_getopt with getopt

This eliminates one location where distutils may be imported on
Python 3.12+, by replacing the logic with mostly equivalent logic.

Author: pradyunsg

src/pip/_internal/utils/distutils_args.py

@@ -1,42 +1,43 @@
-from distutils.errors import DistutilsArgError
-from distutils.fancy_getopt import FancyGetopt
+from getopt import GetoptError, getopt
 from typing import Dict, List
 
 _options = [
-    ("exec-prefix=", None, ""),
-    ("home=", None, ""),
-    ("install-base=", None, ""),
-    ("install-data=", None, ""),
-    ("install-headers=", None, ""),
-    ("install-lib=", None, ""),
-    ("install-platlib=", None, ""),
-    ("install-purelib=", None, ""),
-    ("install-scripts=", None, ""),
-    ("prefix=", None, ""),
-    ("root=", None, ""),
-    ("user", None, ""),
+    "exec-prefix=",
+    "home=",
+    "install-base=",
+    "install-data=",
+    "install-headers=",
+    "install-lib=",
+    "install-platlib=",
+    "install-purelib=",
+    "install-scripts=",
+    "prefix=",
+    "root=",
+    "user",
 ]
 
 
-# typeshed doesn't permit Tuple[str, None, str], see python/typeshed#3469.
-_distutils_getopt = FancyGetopt(_options)  # type: ignore
-
-
 def parse_distutils_args(args: List[str]) -> Dict[str, str]:
-    """Parse provided arguments, returning an object that has the
-    matched arguments.
+    """Parse provided arguments, returning an object that has the matched arguments.
 
     Any unknown arguments are ignored.
     """
     result = {}
     for arg in args:
         try:
-            _, match = _distutils_getopt.getopt(args=[arg])
-        except DistutilsArgError:
+            parsed_opt, _ = getopt(args=[arg], shortopts="", longopts=_options)
+        except GetoptError:
             # We don't care about any other options, which here may be
             # considered unrecognized since our option list is not
             # exhaustive.
-            pass
-        else:
-            result.update(match.__dict__)
+            continue
+
+        if not parsed_opt:
+            continue
+
+        option = parsed_opt[0]
+        name_from_parsed = option[0][2:].replace("-", "_")
+        value_from_parsed = option[1] or "true"
+        result[name_from_parsed] = value_from_parsed
+
     return result

tests/unit/test_utils_distutils_args.py

@@ -60,4 +60,4 @@ def test_all_value_options_work(name: str, value: str) -> None:
 
 def test_user_option_works() -> None:
     result = parse_distutils_args(["--user"])
-    assert result["user"] == 1
+    assert result["user"]