Fix T94162: incorrect handling when there are multiple group outputs

Typically a node group should only have a single Group Output node.
However, currently Blender already supports having multiple group outputs,
one of which is active. This wasn't handled correctly by geometry nodes.

Differential Revision: https://developer.blender.org/D13611

2 files changed, 19 insertions, 0 deletions

diff --git a/source/blender/nodes/intern/derived_node_tree.cc b/source/blender/nodes/intern/derived_node_tree.cc
index dc223f07a26..449c6598307 100644
--- a/source/blender/nodes/intern/derived_node_tree.cc
+++ b/source/blender/nodes/intern/derived_node_tree.cc
@@ -270,6 +270,9 @@ void DOutputSocket::foreach_target_socket(ForeachTargetSocketFn target_fn,
       }
     }
     else if (linked_node->is_group_output_node()) {
+      if (linked_node.node_ref() != context_->tree().group_output_node()) {
+        continue;
+      }
       if (context_->is_root()) {
         /* This is a group output in the root node group. */
         path_info.sockets.append(linked_socket);
diff --git a/source/blender/nodes/intern/node_tree_ref.cc b/source/blender/nodes/intern/node_tree_ref.cc
index ffe0edb9762..bc78533d45c 100644
--- a/source/blender/nodes/intern/node_tree_ref.cc
+++ b/source/blender/nodes/intern/node_tree_ref.cc
@@ -117,6 +117,22 @@ NodeTreeRef::NodeTreeRef(bNodeTree *btree) : btree_(btree)
     const bNodeType *nodetype = node->bnode_->typeinfo;
     nodes_by_type_.add(nodetype, node);
   }
+
+  const Span<const NodeRef *> group_output_nodes = this->nodes_by_type("NodeGroupOutput");
+  if (group_output_nodes.is_empty()) {
+    group_output_node_ = nullptr;
+  }
+  else if (group_output_nodes.size() == 1) {
+    group_output_node_ = group_output_nodes.first();
+  }
+  else {
+    for (const NodeRef *group_output : group_output_nodes) {
+      if (group_output->bnode_->flag & NODE_DO_OUTPUT) {
+        group_output_node_ = group_output;
+        break;
+      }
+    }
+  }
 }
 
 NodeTreeRef::~NodeTreeRef()