gh-85283: Build pwd extension with the limited C API (#116841)

Argument Clinic now uses the PEP 737 "%T" format to format type name
for the limited C API.

Author: vstinner

Doc/whatsnew/3.13.rst

@@ -1469,7 +1469,7 @@ Build Changes
 * Building CPython now requires a compiler with support for the C11 atomic
   library, GCC built-in atomic functions, or MSVC interlocked intrinsics.
 
-* The ``errno``, ``fcntl``, ``grp``, ``md5``, ``resource``, ``winsound``,
+* The ``errno``, ``fcntl``, ``grp``, ``md5``, ``pwd``, ``resource``, ``winsound``,
   ``_ctypes_test``, ``_multiprocessing.posixshmem``, ``_scproxy``, ``_stat``,
   ``_testimportmultiple`` and ``_uuid`` C extensions are now built with the
   :ref:`limited C API <limited-c-api>`.

Misc/NEWS.d/next/C API/2024-03-14-10-33-58.gh-issue-85283.LOgmdU.rst

@@ -1,2 +1,2 @@
-The ``fcntl`` and ``grp`` C extensions are now built with the :ref:`limited
+The ``fcntl``, ``grp`` and ``pwd`` C extensions are now built with the :ref:`limited
 C API <limited-c-api>`. (Contributed by Victor Stinner in :gh:`85283`.)

Modules/clinic/pwdmodule.c.h

@@ -1,9 +1,16 @@
 
 /* UNIX password file access module */
 
+// Need limited C API version 3.13 for PyMem_RawRealloc()
+#include "pyconfig.h"   // Py_GIL_DISABLED
+#ifndef Py_GIL_DISABLED
+#  define Py_LIMITED_API 0x030d0000
+#endif
+
 #include "Python.h"
 #include "posixmodule.h"
 
+#include <errno.h>                // ERANGE
 #include <pwd.h>                  // getpwuid()
 #include <unistd.h>               // sysconf()
 
@@ -83,7 +90,7 @@ mkpwent(PyObject *module, struct passwd *p)
         if (item == NULL) {                                  \
             goto error;                                      \
         }                                                    \
-        PyStructSequence_SET_ITEM(v, setIndex++, item);      \
+        PyStructSequence_SetItem(v, setIndex++, item);       \
     } while(0)
 
     SET_STRING(p->pw_name);

Modules/pwdmodule.c

@@ -426,13 +426,12 @@ def bad_argument(self, displayname: str, expected: str, *, limited_capi: bool, e
         if limited_capi:
             if expected_literal:
                 return (f'PyErr_Format(PyExc_TypeError, '
-                        f'"{{{{name}}}}() {displayname} must be {expected}, not %.50s", '
-                        f'{{argname}} == Py_None ? "None" : Py_TYPE({{argname}})->tp_name);')
+                        f'"{{{{name}}}}() {displayname} must be {expected}, not %T", '
+                        f'{{argname}});')
             else:
                 return (f'PyErr_Format(PyExc_TypeError, '
-                        f'"{{{{name}}}}() {displayname} must be %.50s, not %.50s", '
-                        f'"{expected}", '
-                        f'{{argname}} == Py_None ? "None" : Py_TYPE({{argname}})->tp_name);')
+                        f'"{{{{name}}}}() {displayname} must be %s, not %T", '
+                        f'"{expected}", {{argname}});')
         else:
             if expected_literal:
                 expected = f'"{expected}"'