Fix for incomplete Reroute node updates. Adding reroute nodes by spliting links would often result in unrelated color sockets or otherwise miss updates.

The reason is that the per-node updates used for Reroute node type inheritance are not supposed to be looking at connected nodes, they are purely for "local" updates. For this sort of "global" update which requires depth-first search, the update function on the node tree level must be used instead.

source/blender/blenkernel/intern/node.c

@@ -1660,8 +1660,6 @@ void ntreeUpdateTree(bNodeTree *ntree)
 			else if (node->typeinfo->updatefunc)
 				node->typeinfo->updatefunc(ntree, node);
 		}
-		/* clear update flag */
-		node->update = 0;
 	}
 	
 	/* check link validity */
@@ -1683,7 +1681,10 @@ void ntreeUpdateTree(bNodeTree *ntree)
 	/* XXX hack, should be done by depsgraph!! */
 	ntreeVerifyNodes(G.main, &ntree->id);
 	
-	/* clear the update flag */
+	/* clear update flags */
+	for (node = ntree->nodes.first; node; node = node->next) {
+		node->update = 0;
+	}
 	ntree->update = 0;
 }
 

source/blender/nodes/composite/node_composite_tree.c

@@ -50,6 +50,7 @@
 #include "BKE_tracking.h"
 #include "BKE_utildefines.h"
 
+#include "node_common.h"
 #include "node_exec.h"
 #include "node_util.h"
 
@@ -247,6 +248,8 @@ static void local_merge(bNodeTree *localtree, bNodeTree *ntree)
 static void update(bNodeTree *ntree)
 {
 	ntreeSetOutput(ntree);
+	
+	ntree_update_reroute_nodes(ntree);
 }
 
 bNodeTreeType ntreeType_Composite = {

source/blender/nodes/intern/node_common.c

@@ -580,23 +580,6 @@ static void node_reroute_init(bNodeTree *ntree, bNode* node, bNodeTemplate *UNUS
 	nodeAddSocket(ntree, node, SOCK_OUT, "Output", SOCK_RGBA);
 }
 
-static void node_reroute_update(bNodeTree *UNUSED(ntree), bNode *node)
-{
-	bNodeSocket *input = node->inputs.first;
-	bNodeSocket *output = node->outputs.first;
-	int type = SOCK_FLOAT;
-	
-	/* determine socket type from unambiguous input/output connection if possible */
-	if (input->limit==1 && input->link)
-		type = input->link->fromsock->type;
-	else if (output->limit==1 && output->link)
-			type = output->link->tosock->type;
-	
-	/* same type for input/output */
-	nodeSocketSetType(input, type);
-	nodeSocketSetType(output, type);
-}
-
 void register_node_type_reroute(bNodeTreeType *ttype)
 {
 	/* frame type is used for all tree types, needs dynamic allocation */
@@ -605,8 +588,66 @@ void register_node_type_reroute(bNodeTreeType *ttype)
 	node_type_base(ttype, ntype, NODE_REROUTE, "Reroute", NODE_CLASS_LAYOUT, 0);
 	node_type_init(ntype, node_reroute_init);
 	node_type_internal_connect(ntype, node_reroute_internal_connect);
-	node_type_update(ntype, node_reroute_update, NULL);
 	
 	ntype->needs_free = 1;
 	nodeRegisterType(ttype, ntype);
 }
+
+static void node_reroute_inherit_type_recursive(bNodeTree *ntree, bNode *node)
+{
+	bNodeSocket *input = node->inputs.first;
+	bNodeSocket *output = node->outputs.first;
+	int type = SOCK_FLOAT;
+	bNodeLink *link;
+	
+	/* XXX it would be a little bit more efficient to restrict actual updates
+	 * to rerout nodes connected to an updated node, but there's no reliable flag
+	 * to indicate updated nodes (node->update is not set on linking).
+	 */
+	
+	node->done = 1;
+	
+	/* recursive update */
+	for (link = ntree->links.first; link; link = link->next)
+	{
+		bNode *fromnode = link->fromnode;
+		bNode *tonode = link->tonode;
+		if (!tonode || !fromnode)
+			continue;
+		
+		if (tonode == node && fromnode->type == NODE_REROUTE && !fromnode->done)
+			node_reroute_inherit_type_recursive(ntree, fromnode);
+		
+		if (fromnode == node && tonode->type == NODE_REROUTE && !tonode->done)
+			node_reroute_inherit_type_recursive(ntree, tonode);
+	}
+	
+	/* determine socket type from unambiguous input/output connection if possible */
+	if (input->limit==1 && input->link)
+		type = input->link->fromsock->type;
+	else if (output->limit==1 && output->link)
+		type = output->link->tosock->type;
+	
+	/* arbitrary, could also test output->type, both are the same */
+	if (input->type != type) {
+		/* same type for input/output */
+		nodeSocketSetType(input, type);
+		nodeSocketSetType(output, type);
+	}
+}
+
+/* Global update function for Reroute node types.
+ * This depends on connected nodes, so must be done as a tree-wide update.
+ */
+void ntree_update_reroute_nodes(bNodeTree *ntree)
+{
+	bNode *node;
+	
+	/* clear tags */
+	for (node = ntree->nodes.first; node; node = node->next)
+		node->done = 0;
+	
+	for (node = ntree->nodes.first; node; node = node->next)
+		if (node->type == NODE_REROUTE && !node->done)
+			node_reroute_inherit_type_recursive(ntree, node);
+}

source/blender/nodes/intern/node_common.h

@@ -59,4 +59,6 @@ void node_group_edit_clear(bNode *node);
 
 void node_loop_update_tree(struct bNodeTree *ngroup);
 
+void ntree_update_reroute_nodes(struct bNodeTree *ntree);
+
 #endif

source/blender/nodes/shader/node_shader_tree.c

@@ -55,6 +55,7 @@
 
 #include "RE_shader_ext.h"
 
+#include "node_common.h"
 #include "node_exec.h"
 #include "node_util.h"
 #include "node_shader_util.h"
@@ -133,6 +134,8 @@ static void local_sync(bNodeTree *localtree, bNodeTree *ntree)
 static void update(bNodeTree *ntree)
 {
 	ntreeSetOutput(ntree);
+	
+	ntree_update_reroute_nodes(ntree);
 }
 
 bNodeTreeType ntreeType_Shader = {

source/blender/nodes/texture/node_texture_tree.c

@@ -45,6 +45,7 @@
 #include "BKE_main.h"
 #include "BKE_node.h"
 
+#include "node_common.h"
 #include "node_exec.h"
 #include "node_util.h"
 #include "NOD_texture.h"
@@ -112,6 +113,11 @@ static void local_sync(bNodeTree *localtree, bNodeTree *ntree)
 	}
 }
 
+static void update(bNodeTree *ntree)
+{
+	ntree_update_reroute_nodes(ntree);
+}
+
 bNodeTreeType ntreeType_Texture = {
 	/* type */				NTREE_TEXTURE,
 	/* id_name */			"NTTexture Nodetree",
@@ -125,7 +131,7 @@ bNodeTreeType ntreeType_Texture = {
 	/* localize */			localize,
 	/* local_sync */		local_sync,
 	/* local_merge */		NULL,
-	/* update */			NULL,
+	/* update */			update,
 	/* update_node */		NULL,
 	/* validate_link */		NULL,
 	/* internal_connect */	node_internal_connect_default