Make pkgcontext a thread-local variable.

ericsnowcurrently · ericsnowcurrently · commit 83bbb3ae32b7 · 2023-06-13T11:55:00.000-06:00
diff --git a/Python/import.c b/Python/import.c
@@ -703,28 +703,43 @@ _PyImport_ClearModulesByIndex(PyInterpreterState *interp)
    _PyRuntime.imports.pkgcontext, and PyModule_Create*() will
    substitute this (if the name actually matches).
 */
+
+#ifdef HAVE_THREAD_LOCAL
+_Py_thread_local const char *pkgcontext = NULL;
+# undef PKGCONTEXT
+# define PKGCONTEXT pkgcontext
+#endif
+
 const char *
 _PyImport_ResolveNameWithPackageContext(const char *name)
 {
+#ifndef HAVE_THREAD_LOCAL
     PyThread_acquire_lock(EXTENSIONS.mutex, WAIT_LOCK);
+#endif
     if (PKGCONTEXT != NULL) {
         const char *p = strrchr(PKGCONTEXT, '.');
         if (p != NULL && strcmp(name, p+1) == 0) {
             name = PKGCONTEXT;
             PKGCONTEXT = NULL;
         }
     }
+#ifndef HAVE_THREAD_LOCAL
     PyThread_release_lock(EXTENSIONS.mutex);
+#endif
     return name;
 }
 
 const char *
 _PyImport_SwapPackageContext(const char *newcontext)
 {
+#ifndef HAVE_THREAD_LOCAL
     PyThread_acquire_lock(EXTENSIONS.mutex, WAIT_LOCK);
+#endif
     const char *oldcontext = PKGCONTEXT;
     PKGCONTEXT = newcontext;
+#ifndef HAVE_THREAD_LOCAL
     PyThread_release_lock(EXTENSIONS.mutex);
+#endif
     return oldcontext;
 }
 
