Added a test that checks socket propagation into an embedded BlendTree.

src/AnimGraph/AnimGraphBlendTree.h

@@ -24,8 +24,8 @@ struct AnimGraphBlendTree : public AnimNode {
   char* m_connection_data_storage = nullptr;
   char* m_const_node_inputs = nullptr;
 
-  std::vector<Socket>& getGraphOutputs() { return m_node_descriptor->m_inputs; }
-  std::vector<Socket>& getGraphInputs() { return m_node_descriptor->m_outputs; }
+  std::vector<Socket>& GetGraphOutputs() { return m_node_descriptor->m_inputs; }
+  std::vector<Socket>& GetGraphInputs() { return m_node_descriptor->m_outputs; }
 
   AnimDataAllocator m_anim_data_allocator;
 

src/AnimGraph/AnimGraphResource.cc

@@ -397,8 +397,17 @@ bool BlendTreeResource::ConnectSockets(
         source_socket_name.c_str());
   }
 
-  if (source_socket == nullptr || target_socket == nullptr) {
-    std::cerr << "Cannot connect nodes: could not find sockets." << std::endl;
+  if (source_socket == nullptr) {
+    std::cerr << "Cannot connect nodes: could not find source socket '"
+              << source_socket_name << "'." << std::endl;
+  }
+
+  if (target_socket == nullptr) {
+    std::cerr << "Cannot connect nodes: could not find target socket '"
+              << target_socket_name << "'." << std::endl;
+  }
+
+  if (target_socket == nullptr || source_socket == nullptr) {
     return false;
   }
 
@@ -539,7 +548,7 @@ void AnimGraphResource::PrepareBlendTreeIOData(
   // graph inputs
   //
   int input_block_size = 0;
-  std::vector<Socket>& graph_inputs = instance.getGraphInputs();
+  std::vector<Socket>& graph_inputs = instance.GetGraphInputs();
   for (int i = 0; i < graph_inputs.size(); i++) {
     input_block_size += sizeof(void*);
   }
@@ -562,7 +571,7 @@ void AnimGraphResource::PrepareBlendTreeIOData(
   // graph outputs
   //
   int output_block_size = 0;
-  std::vector<Socket>& graph_outputs = instance.getGraphOutputs();
+  std::vector<Socket>& graph_outputs = instance.GetGraphOutputs();
   for (int i = 0; i < graph_outputs.size(); i++) {
     output_block_size += sizeof(void*);
   }
@@ -697,6 +706,12 @@ void AnimGraphResource::CreateBlendTreeConnectionInstances(
             == target_socket->m_name) {
           embedded_target_connection.m_source_node = source_node;
           embedded_target_connection.m_crosses_hierarchy = true;
+
+          // In addition: make sure we expose the embedded socket to the
+          // connection in the parent blend tree. That way
+          // parent_tree.SetValue<>() correctly propagates the value to the
+          // embedded node socket.
+          target_socket = &embedded_target_connection.m_target_socket;
         }
       }
     }