third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/python/google/protobuf/internal/testing_refleaks.py

+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc.  All rights reserved.
+# https://developers.google.com/protocol-buffers/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""A subclass of unittest.TestCase which checks for reference leaks.
+
+To use:
+- Use testing_refleak.BaseTestCase instead of unittest.TestCase
+- Configure and compile Python with --with-pydebug
+
+If sys.gettotalrefcount() is not available (because Python was built without
+the Py_DEBUG option), then this module is a no-op and tests will run normally.
+"""
+
+import gc
+import sys
+
+try:
+  import copy_reg as copyreg  #PY26
+except ImportError:
+  import copyreg
+
+try:
+  import unittest2 as unittest  #PY26
+except ImportError:
+  import unittest
+
+
+class LocalTestResult(unittest.TestResult):
+  """A TestResult which forwards events to a parent object, except for Skips."""
+
+  def __init__(self, parent_result):
+    unittest.TestResult.__init__(self)
+    self.parent_result = parent_result
+
+  def addError(self, test, error):
+    self.parent_result.addError(test, error)
+
+  def addFailure(self, test, error):
+    self.parent_result.addFailure(test, error)
+
+  def addSkip(self, test, reason):
+    pass
+
+
+class ReferenceLeakCheckerTestCase(unittest.TestCase):
+  """A TestCase which runs tests multiple times, collecting reference counts."""
+
+  NB_RUNS = 3
+
+  def run(self, result=None):
+    # python_message.py registers all Message classes to some pickle global
+    # registry, which makes the classes immortal.
+    # We save a copy of this registry, and reset it before we could references.
+    self._saved_pickle_registry = copyreg.dispatch_table.copy()
+
+    # Run the test twice, to warm up the instance attributes.
+    super(ReferenceLeakCheckerTestCase, self).run(result=result)
+    super(ReferenceLeakCheckerTestCase, self).run(result=result)
+
+    oldrefcount = 0
+    local_result = LocalTestResult(result)
+
+    refcount_deltas = []
+    for _ in range(self.NB_RUNS):
+      oldrefcount = self._getRefcounts()
+      super(ReferenceLeakCheckerTestCase, self).run(result=local_result)
+      newrefcount = self._getRefcounts()
+      refcount_deltas.append(newrefcount - oldrefcount)
+    print(refcount_deltas, self)
+
+    try:
+      self.assertEqual(refcount_deltas, [0] * self.NB_RUNS)
+    except Exception:  # pylint: disable=broad-except
+      result.addError(self, sys.exc_info())
+
+  def _getRefcounts(self):
+    copyreg.dispatch_table.clear()
+    copyreg.dispatch_table.update(self._saved_pickle_registry)
+    # It is sometimes necessary to gc.collect() multiple times, to ensure
+    # that all objects can be collected.
+    gc.collect()
+    gc.collect()
+    gc.collect()
+    return sys.gettotalrefcount()
+
+
+if hasattr(sys, 'gettotalrefcount'):
+  BaseTestCase = ReferenceLeakCheckerTestCase
+  SkipReferenceLeakChecker = unittest.skip
+
+else:
+  # When PyDEBUG is not enabled, run the tests normally.
+  BaseTestCase = unittest.TestCase
+
+  def SkipReferenceLeakChecker(reason):
+    del reason  # Don't skip, so don't need a reason.
+    def Same(func):
+      return func
+    return Same