Issue #15894: Document why we don't worry about re-acquiring the
global import lock after forking.
diff --git a/Python/import.c b/Python/import.c
index 2f71b97..6882b57 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -202,8 +202,11 @@
if (import_lock_level > 1) {
/* Forked as a side effect of import */
long me = PyThread_get_thread_ident();
- PyThread_acquire_lock(import_lock, 0);
- /* XXX: can the previous line fail? */
+ /* The following could fail if the lock is already held, but forking as
+ a side-effect of an import is a) rare, b) nuts, and c) difficult to
+ do thanks to the lock only being held when doing individual module
+ locks per import. */
+ PyThread_acquire_lock(import_lock, NOWAIT_LOCK);
import_lock_thread = me;
import_lock_level--;
} else {