1 files changed, 30 insertions, 15 deletions

diff --git a/source/blender/editors/space_node/node_group.c b/source/blender/editors/space_node/node_group.c
index cf6e2ac226e..26eeaa91dd0 100644
--- a/source/blender/editors/space_node/node_group.c
+++ b/source/blender/editors/space_node/node_group.c
@@ -794,22 +794,37 @@ static void node_group_make_insert_selected(const bContext *C, bNodeTree *ntree,
 			link->tosock = node_group_find_input_socket(gnode, iosock->identifier);
 		}
 		else if (fromselect) {
-			bNodeSocket *iosock = ntreeAddSocketInterfaceFromSocket(ngroup, link->fromnode, link->fromsock);
-			bNodeSocket *output_sock;
-			
-			/* update the group node and interface node sockets,
-			 * so the new interface socket can be linked.
-			 */
-			node_group_verify(ntree, gnode, (ID *)ngroup);
-			node_group_output_verify(ngroup, output_node, (ID *)ngroup);
+			/* First check whether the source of this link is already connected to an output.
+			 * If yes, reuse that output instead of duplicating it. */
+			bool connected = false;
+			bNodeLink *olink;
+			for (olink = ngroup->links.first; olink; olink = olink->next) {
+				if (olink->fromsock == link->fromsock && olink->tonode == output_node) {
+					bNodeSocket *output_sock = node_group_find_output_socket(gnode, olink->tosock->identifier);
+					link->fromnode = gnode;
+					link->fromsock = output_sock;
+					connected = true;
+				}
+			}
 
-			/* create new internal link */
-			output_sock = node_group_output_find_socket(output_node, iosock->identifier);
-			nodeAddLink(ngroup, link->fromnode, link->fromsock, output_node, output_sock);
-			
-			/* redirect external link */
-			link->fromnode = gnode;
-			link->fromsock = node_group_find_output_socket(gnode, iosock->identifier);
+			if (!connected) {
+				bNodeSocket *iosock = ntreeAddSocketInterfaceFromSocket(ngroup, link->fromnode, link->fromsock);
+				bNodeSocket *output_sock;
+
+				/* update the group node and interface node sockets,
+				 * so the new interface socket can be linked.
+				 */
+				node_group_verify(ntree, gnode, (ID *)ngroup);
+				node_group_output_verify(ngroup, output_node, (ID *)ngroup);
+
+				/* create new internal link */
+				output_sock = node_group_output_find_socket(output_node, iosock->identifier);
+				nodeAddLink(ngroup, link->fromnode, link->fromsock, output_node, output_sock);
+
+				/* redirect external link */
+				link->fromnode = gnode;
+				link->fromsock = node_group_find_output_socket(gnode, iosock->identifier);
+			}
 		}
 	}