add blocks attr type in proto

paddle/fluid/framework/framework.proto

@@ -27,6 +27,7 @@ enum AttrType {
   BOOLEANS = 7;
   BLOCK = 8;
   LONG = 9;
+  BLOCKS = 10;
 }
 
 // OpDesc describes an instance of a C++ framework::OperatorBase

paddle/fluid/operators/listen_and_serv_op.cc

@@ -342,7 +342,8 @@ class ListenAndServOpMaker : public framework::OpProtoAndCheckerMaker {
         .SetDefault({});
     AddAttr<bool>("sync_mode", "if works at sync_mode or not").SetDefault(true);
     AddAttr<std::vector<framework::BlockDesc *>>(
-        kOptimizeBlocks, "Optimize blocks to run on server side.");
+        kOptimizeBlocks, "Optimize blocks to run on server side.")
+        .SetDefault({});
     AddAttr<std::vector<std::string>>(kPrefetchVarNameToBlockId,
                                       "prefetch blocks to run on server side.")
         .SetDefault({});

paddle/fluid/pybind/protobuf.cc

@@ -268,7 +268,8 @@ void BindOpDesc(pybind11::module *m) {
       .value("STRINGS", pd::proto::AttrType::STRINGS)
       .value("BOOL", pd::proto::AttrType::BOOLEAN)
       .value("BOOLS", pd::proto::AttrType::BOOLEANS)
-      .value("BLOCK", pd::proto::AttrType::BLOCK);
+      .value("BLOCK", pd::proto::AttrType::BLOCK)
+      .value("BLOCKS", pd::proto::AttrType::BLOCKS);
 
   pybind11::class_<pd::OpDesc> op_desc(*m, "OpDesc", "");
   op_desc