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.

diff --git a/Lib/test/support.py b/Lib/test/support.py
index 0c69aac6deafcda464ee2956db6c35e1a412a822..7b0241aacc5fe33084d4338662e6909f94a04392 100644 (file)
--- a/Lib/test/support.py
+++ b/Lib/test/support.py
@@ -951,6 +951,23 @@ 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
 

diff --git a/Lib/test/test_importhooks.py b/Lib/test/test_importhooks.py
index bf2870dbec5d283417dbee5743919337a531382e..1da30b7c7743c8f5b08eb60c5275db8752b7dfa8 100644 (file)
--- a/Lib/test/test_importhooks.py
+++ b/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):

diff --git a/Lib/test/test_pkg.py b/Lib/test/test_pkg.py
index 0c568bb3b55e1e68bdf8834f49c3ab0fc0588777..2e293f4fbe537022091bf09a36797da27aea7f58 100644 (file)
--- a/Lib/test/test_pkg.py
+++ b/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

diff --git a/Misc/NEWS b/Misc/NEWS
index 2d30d504d65cdbf31d2c6ed90d754adb36f90a0f..a7b570c46144e37a56f2cb7734407b5fce688b9a 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -373,6 +373,11 @@ Documentation
 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