Stackless issue python#81: adapt the interpreter shutdown test to newer versions of Python 3.

Anselm Kruis · Anselm Kruis · commit 011078af535e · 2016-11-06T23:13:01.000+01:00
The 2.7 detector hook (cleanup of codecs search path) does not work with Python 3.3 and later.
Adapt the test cases to use a different hook (builtins._).
diff --git a/Stackless/test/test_interpreter_shutdown.py b/Stackless/test/test_interpreter_shutdown.py
@@ -2,7 +2,7 @@
 import sys
 import _thread as thread
 import stackless
-import codecs
+import builtins
 import os
 import time
 import collections
@@ -63,13 +63,14 @@ def __init__(self, out, checks, tasklets):
         self.checks = checks
         self.tasklets = tasklets
 
-        # register the detector in the codecs search path
-        # it will be cleared after clearing the thread states
-        # this way the detector runs very late
-        def dummy_codecs_search_function(name):
-            return None
-        codecs.register(dummy_codecs_search_function)
-        dummy_codecs_search_function.x = self
+        # In Py_Finalize() the PyImport_Cleanup() runs shortly after 
+        # slp_kill_tasks_with_stacks(NULL).
+        # As very first action of PyImport_Cleanup() the Python
+        # interpreter sets builtins._ to None.
+        # Therefore we can use this assignment to trigger the execution
+        # of this detector. At this point the interpreter is still almost fully
+        # intact.
+        builtins._ = self
 
     def __del__(self):
         if self.debug:
diff --git a/Stackless/unittests/test_shutdown.py b/Stackless/unittests/test_shutdown.py
@@ -35,7 +35,7 @@
 from __future__ import print_function, absolute_import, division
 import sys
 import stackless
-import codecs
+import builtins
 import os
 import time
 import collections
@@ -220,13 +220,14 @@ def __init__(self, out, checks, tasklets):
         self.checks = checks
         self.tasklets = tasklets
 
-        # register the detector in the codecs search path
-        # it will be cleared after clearing the thread states
-        # this way the detector runs very late
-        def dummy_codecs_search_function(name):
-            return None
-        codecs.register(dummy_codecs_search_function)
-        dummy_codecs_search_function.x = self
+        # In Py_Finalize() the PyImport_Cleanup() runs shortly after 
+        # slp_kill_tasks_with_stacks(NULL).
+        # As very first action of PyImport_Cleanup() the Python
+        # interpreter sets builtins._ to None.
+        # Therefore we can use this assignment to trigger the execution
+        # of this detector. At this point the interpreter is still almost fully
+        # intact.
+        builtins._ = self
 
     def __del__(self):
         if self.debug:
@@ -405,7 +406,7 @@ def interpreter_shutdown_test():
     test = Test()
     detector = Detector(test.out, test.checks, test.tasklets)
     assert sys.getrefcount(detector) - sys.getrefcount(object()) == 2
-    detector = None  # the last ref is now in the codecs search path
+    detector = None  # the last ref is now in bultins._
     thread.start_new_thread(test.other_thread_main, ())
     ready.acquire()  # Be sure the other thread is ready.
     # print("at end")
