gh-152798: Return 'pymutex' on POSIX except Windows/WASI

Author: Wojusensei

Misc/NEWS.d/next/Library/2026-07-03-gh-152994.gh-issue-152798.0ba1f2.rst

@@ -0,0 +1 @@
+Reverted :data:`sys.thread_info.lock` on POSIX platforms (except Windows and WASI) back to ``"pymutex"`` to align with test expectations. Windows and WASI continue to return ``None``.

Python/thread.c

@@ -334,13 +334,20 @@ PyThread_GetInfo(void)
 
 #ifdef HAVE_PTHREAD_STUBS
     value = Py_NewRef(Py_None);
+#else
+#ifdef MS_WINDOWS
+    value = Py_NewRef(Py_None);
+#elif defined(__wasi__)
+    value = Py_NewRef(Py_None);
 #else
     value = PyUnicode_FromString("pymutex");
     if (value == NULL) {
         Py_DECREF(threadinfo);
         return NULL;
     }
 #endif
+#endif
+
     PyStructSequence_SET_ITEM(threadinfo, pos++, value);
 
 #if (defined(_POSIX_THREADS) && defined(HAVE_CONFSTR) \
@@ -361,7 +368,6 @@ PyThread_GetInfo(void)
     return threadinfo;
 }
 
-
 void
 _PyThread_FiniType(PyInterpreterState *interp)
 {