Integrated internal changes from Google

1 files changed, 35 insertions, 4 deletions

diff --git a/python/google/protobuf/internal/api_implementation.py b/python/google/protobuf/internal/api_implementation.py
index 422af590..bce71bb8 100755
--- a/python/google/protobuf/internal/api_implementation.py
+++ b/python/google/protobuf/internal/api_implementation.py
@@ -61,10 +61,15 @@ if _api_version < 0:  # Still unspecified?
     del _use_fast_cpp_protos
     _api_version = 2
   except ImportError:
-    if _proto_extension_modules_exist_in_build:
-      if sys.version_info[0] >= 3:  # Python 3 defaults to C++ impl v2.
-        _api_version = 2
-      # TODO(b/17427486): Make Python 2 default to C++ impl v2.
+    try:
+      # pylint: disable=g-import-not-at-top
+      from google.protobuf.internal import use_pure_python
+      del use_pure_python  # Avoids a pylint error and namespace pollution.
+    except ImportError:
+      if _proto_extension_modules_exist_in_build:
+        if sys.version_info[0] >= 3:  # Python 3 defaults to C++ impl v2.
+          _api_version = 2
+          # TODO(b/17427486): Make Python 2 default to C++ impl v2.
 
 _default_implementation_type = (
     'python' if _api_version <= 0 else 'cpp')
@@ -137,3 +142,29 @@ def Version():
 # For internal use only
 def IsPythonDefaultSerializationDeterministic():
   return _python_deterministic_proto_serialization
+
+# DO NOT USE: For migration and testing only. Will be removed when Proto3
+# defaults to preserve unknowns.
+if _implementation_type == 'cpp':
+  try:
+    # pylint: disable=g-import-not-at-top
+    from google.protobuf.pyext import _message
+
+    def GetPythonProto3PreserveUnknownsDefault():
+      return _message.GetPythonProto3PreserveUnknownsDefault()
+
+    def SetPythonProto3PreserveUnknownsDefault(preserve):
+      _message.SetPythonProto3PreserveUnknownsDefault(preserve)
+  except ImportError:
+    # Unrecognized cpp implementation. Skipping the unknown fields APIs.
+    pass
+else:
+  _python_proto3_preserve_unknowns_default = False
+
+  def GetPythonProto3PreserveUnknownsDefault():
+    return _python_proto3_preserve_unknowns_default
+
+  def SetPythonProto3PreserveUnknownsDefault(preserve):
+    global _python_proto3_preserve_unknowns_default
+    _python_proto3_preserve_unknowns_default = preserve
+