Merged revisions 76240 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r76240 | antoine.pitrou | 2009-11-13 17:29:04 +0100 (ven., 13 nov. 2009) | 6 lines

  Issue #6551: test_zipimport could import and then destroy some modules of
  the encodings package, which would make other tests fail further down
  the road because the internally cached encoders and decoders would point
  to empty global variables.
........

Lib/test/support.py

@@ -919,6 +919,23 @@ def run_doctest(module, verbosity=None):
               (module.__name__, t))
     return f, t
 
+
+#=======================================================================
+# Support for saving and restoring the imported modules.
+
+def modules_setup():
+    return sys.modules.copy(),
+
+def modules_cleanup(oldmodules):
+    # Encoders/decoders are registered permanently within the internal
+    # codec cache. If we destroy the corresponding modules their
+    # globals will be set to None which will trip up the cached functions.
+    encodings = [(k, v) for k, v in sys.modules.items()
+                 if k.startswith('encodings.')]
+    sys.modules.clear()
+    sys.modules.update(encodings)
+    sys.modules.update(oldmodules)
+
 #=======================================================================
 # Threading support to prevent reporting refleaks when running regrtest.py -R
 

Lib/test/test_importhooks.py

@@ -143,15 +143,14 @@ class ImportHooksBaseTestCase(unittest.TestCase):
         self.meta_path = sys.meta_path[:]
         self.path_hooks = sys.path_hooks[:]
         sys.path_importer_cache.clear()
-        self.modules_before = sys.modules.copy()
+        self.modules_before = support.modules_setup()
 
     def tearDown(self):
         sys.path[:] = self.path
         sys.meta_path[:] = self.meta_path
         sys.path_hooks[:] = self.path_hooks
         sys.path_importer_cache.clear()
-        sys.modules.clear()
-        sys.modules.update(self.modules_before)
+        support.modules_cleanup(*self.modules_before)
 
 
 class ImportHooksTestCase(ImportHooksBaseTestCase):

Lib/test/test_pkg.py

@@ -48,13 +48,11 @@ class TestPkg(unittest.TestCase):
         self.root = None
         self.pkgname = None
         self.syspath = list(sys.path)
-        self.sysmodules = sys.modules.copy()
+        self.modules_before = support.modules_setup()
 
     def tearDown(self):
         sys.path[:] = self.syspath
-        sys.modules.clear()
-        sys.modules.update(self.sysmodules)
-        del self.sysmodules
+        support.modules_cleanup(*self.modules_before)
         cleanout(self.root)
 
         # delete all modules concerning the tested hiearchy

Misc/NEWS

@@ -144,6 +144,11 @@ Extension Modules
 Tests
 -----
 
+- Issue #6551: test_zipimport could import and then destroy some modules of
+  the encodings package, which would make other tests fail further down
+  the road because the internally cached encoders and decoders would point
+  to empty global variables.
+
 - Issue #7295: Do not use a hardcoded file name in test_tarfile.
 
 - Issue #7270: Add some dedicated unit tests for multi-thread synchronization