Fix subprocess.Popen.__del__() fox Python shutdown

vstinner · vstinner · commit 9505b03bb0d3 · 2017-01-06T10:44:44.000+01:00
Issue #29174, #26741: subprocess.Popen.__del__() now keeps a strong reference to warnings.warn() function.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
@@ -750,15 +750,15 @@ def __exit__(self, type, value, traceback):
             # Wait for the process to terminate, to avoid zombies.
             self.wait()
 
-    def __del__(self, _maxsize=sys.maxsize):
+    def __del__(self, _maxsize=sys.maxsize, _warn=warnings.warn):
         if not self._child_created:
             # We didn't get to successfully create a child process.
             return
         if self.returncode is None:
             # Not reading subprocess exit status creates a zombi process which
             # is only destroyed at the parent python process exit
-            warnings.warn("subprocess %s is still running" % self.pid,
-                          ResourceWarning, source=self)
+            _warn("subprocess %s is still running" % self.pid,
+                  ResourceWarning, source=self)
         # In case the child hasn't been waited on, check if it's done.
         self._internal_poll(_deadstate=_maxsize)
         if self.returncode is None and _active is not None:
