The atexit module effectively turned itself off if sys.exitfunc already

existed at the time atexit first got imported.  That's a bug, and this
fixes it.

Also reworked test_atexit.py to test for this too, and to stop using
an "expected output" file, and to test what actually happens at exit
instead of just simulating what it thinks atexit will do at exit.

Bugfix candidate, but it's messy so I'll backport to 2.2 myself.

1 files changed, 5 insertions, 9 deletions

diff --git a/Lib/atexit.py b/Lib/atexit.py
index 61f2458dd0..b5929fc15a 100644
--- a/Lib/atexit.py
+++ b/Lib/atexit.py
@@ -29,15 +29,11 @@ def register(func, *targs, **kargs):
     _exithandlers.append((func, targs, kargs))
 
 import sys
-try:
-    x = sys.exitfunc
-except AttributeError:
-    sys.exitfunc = _run_exitfuncs
-else:
-    # if x isn't our own exit func executive, assume it's another
-    # registered exit function - append it to our list...
-    if x != _run_exitfuncs:
-        register(x)
+if hasattr(sys, "exitfunc"):
+    # Assume it's another registered exit function - append it to our list
+    register(sys.exitfunc)
+sys.exitfunc = _run_exitfuncs
+
 del sys
 
 if __name__ == "__main__":