Patch packaging to support PEP 703 (--disable-gil)

This applies pypa/packaging#728 as a stopgap
measure to support the free-threaded builds of CPython. That PR is
already merged upstream, but a full upgrade of the packaging library is
more complicated due to removal of legacy versions and version
specifiers.

Closes pypa#12634

src/pip/_vendor/packaging/tags.py

@@ -4,6 +4,7 @@
 
 import logging
 import platform
+import re
 import sys
 import sysconfig
 from importlib.machinery import EXTENSION_SUFFIXES
@@ -122,20 +123,37 @@ def _normalize_string(string: str) -> str:
     return string.replace(".", "_").replace("-", "_")
 
 
-def _abi3_applies(python_version: PythonVersion) -> bool:
+def _is_threaded_cpython(abis: List[str]) -> bool:
+    """
+    Determine if the ABI corresponds to a threaded (`--disable-gil`) build.
+
+    The threaded builds are indicated by a "t" in the abiflags.
+    """
+    if len(abis) == 0:
+        return False
+    # expect e.g., cp313
+    m = re.match(r"cp\d+(.*)", abis[0])
+    if not m:
+        return False
+    abiflags = m.group(1)
+    return "t" in abiflags
+
+
+def _abi3_applies(python_version: PythonVersion, threading: bool) -> bool:
     """
     Determine if the Python version supports abi3.
 
-    PEP 384 was first implemented in Python 3.2.
+    PEP 384 was first implemented in Python 3.2. The threaded (`--disable-gil`)
+    builds do not support abi3.
     """
-    return len(python_version) > 1 and tuple(python_version) >= (3, 2)
+    return len(python_version) > 1 and tuple(python_version) >= (3, 2) and not threading
 
 
 def _cpython_abis(py_version: PythonVersion, warn: bool = False) -> List[str]:
     py_version = tuple(py_version)  # To allow for version comparison.
     abis = []
     version = _version_nodot(py_version[:2])
-    debug = pymalloc = ucs4 = ""
+    threading = debug = pymalloc = ucs4 = ""
     with_debug = _get_config_var("Py_DEBUG", warn)
     has_refcount = hasattr(sys, "gettotalrefcount")
     # Windows doesn't set Py_DEBUG, so checking for support of debug-compiled
@@ -144,6 +162,8 @@ def _cpython_abis(py_version: PythonVersion, warn: bool = False) -> List[str]:
     has_ext = "_d.pyd" in EXTENSION_SUFFIXES
     if with_debug or (with_debug is None and (has_refcount or has_ext)):
         debug = "d"
+    if py_version >= (3, 13) and _get_config_var("Py_NOGIL", warn):
+        threading = "t"
     if py_version < (3, 8):
         with_pymalloc = _get_config_var("WITH_PYMALLOC", warn)
         if with_pymalloc or with_pymalloc is None:
@@ -157,13 +177,8 @@ def _cpython_abis(py_version: PythonVersion, warn: bool = False) -> List[str]:
     elif debug:
         # Debug builds can also load "normal" extension modules.
         # We can also assume no UCS-4 or pymalloc requirement.
-        abis.append(f"cp{version}")
-    abis.insert(
-        0,
-        "cp{version}{debug}{pymalloc}{ucs4}".format(
-            version=version, debug=debug, pymalloc=pymalloc, ucs4=ucs4
-        ),
-    )
+        abis.append(f"cp{version}{threading}")
+    abis.insert(0, f"cp{version}{threading}{debug}{pymalloc}{ucs4}")
     return abis
 
 
@@ -211,11 +226,14 @@ def cpython_tags(
     for abi in abis:
         for platform_ in platforms:
             yield Tag(interpreter, abi, platform_)
-    if _abi3_applies(python_version):
+
+    threading = _is_threaded_cpython(abis)
+    use_abi3 = _abi3_applies(python_version, threading)
+    if use_abi3:
         yield from (Tag(interpreter, "abi3", platform_) for platform_ in platforms)
     yield from (Tag(interpreter, "none", platform_) for platform_ in platforms)
 
-    if _abi3_applies(python_version):
+    if use_abi3:
         for minor_version in range(python_version[1] - 1, 1, -1):
             for platform_ in platforms:
                 interpreter = "cp{version}".format(