Linking with both -lprotobuf and -lprotobuf-lite

[abuszta]

Hello,

I had my C++ binary linked dynamically together by accident with -lprotobuf and -lprotobuf-lite. Therefore after my commits (pull request #43) I noticed that binary is executing google::protobuf::internal::InitializeDefaultRepeatedFields twice and crashing after calling google::protobuf::internal::DestroyDefaultRepeatedFields second time (once for protobuf and once for protobuf-lite). Because this operates on one memory (global variables are overridden on second initialization) there is double free...

Is this valid scenario? Having two libraries linked in? Or should I fix this crash? This can be easily fixed by using GoogleOnceInit however I don't know if this is worth fixing...

What do you think?

diff --git a/src/google/protobuf/extension_set.cc b/src/google/protobuf/extension_set.cc
index 274554b..579ae31 100644
--- a/src/google/protobuf/extension_set.cc
+++ b/src/google/protobuf/extension_set.cc
@@ -1618,10 +1618,11 @@ PROTOBUF_DEFINE_DEFAULT_REPEATED(bool)

 #undef PROTOBUF_DEFINE_DEFAULT_REPEATED

+GOOGLE_PROTOBUF_DECLARE_ONCE(repeated_fields_init);
+
 struct StaticDefaultRepeatedFieldsInitializer {
   StaticDefaultRepeatedFieldsInitializer() {
-    InitializeDefaultRepeatedFields();
-    OnShutdown(&DestroyDefaultRepeatedFields);
+    GoogleOnceInit(&repeated_fields_init, &InitializeDefaultRepeatedFields);
   }
 } static_repeated_fields_initializer;

@@ -1644,6 +1645,7 @@ void InitializeDefaultRepeatedFields() {
       new RepeatedField<float>;
   RepeatedPrimitiveGenericTypeTraits::default_repeated_field_bool_ =
       new RepeatedField<bool>;
+  OnShutdown(&DestroyDefaultRepeatedFields);
 }

 void DestroyDefaultRepeatedFields() {

[xfxyjwf]

I don't think linking with both -lprotobuf and -lprotobuf-lite is a supported use case. -lprotobuf has a duplicate version of everything that -lprotobuf-lite has. You should only link with one of them.

[abuszta]

Ok, thanks. I wanted to be sure :)

[avtomaton]

I have the same problem, but my case is some more complex: I have already compiled dynamic libraries (i. e. from packages) used in my binary, and one of them was linked with '-lprotobuf', and the second with '-lprotobuf-lite'. I suppose that so trivial fix can be accepted to avoid this weird behaviour...