backport blender 3.4 mix shader node to 3.3 mix rgb node

blender_mixrgb_fix_3.3.py

import bpy

def changeNodes(objNodeTree):
    for objNode in objNodeTree.nodes:
        if objNode.type == 'GROUP' and objNode.node_tree:
            changeNodes(objNode.node_tree)
        # look for the generic mix node from 3.4 to try and make it mixrgb in 3.3 
        # [0]Factor, [2]A, [4]B == [0]fac, [1]color1, [2]color2
        
        elif objNode.type=='' and objNode.inputs[0].name == 'Factor': 
        # objNode.inputs[0].name == 'Factor' and objNode.inputs[2].name == 'A' and objNode.inputs[4].name == 'B':
            # look for the target node type
            objNewNode = objNodeTree.nodes.new(type='ShaderNodeMixRGB')
            objNewNode.inputs[0].default_value = objNode.inputs[0].default_value
            #objNewNode.inputs[1].default_value = objNode.inputs[2].default_value
            #objNewNode.inputs[2].default_value = objNode.inputs[4].default_value
            # look for the links
            for objLink in objNodeTree.links:
                # combined so we dont need to loop 2x, conditions are cheaper than loops
                if objLink.from_node.name == objNode.name:
                    # connect to the new one
                    objNodeTree.links.new(objNewNode.outputs[0], objLink.to_socket)
                elif objLink.to_node.location == objNode.location and objLink.to_node == objNode:
                    print(objLink.to_node.name,objNode.name)
                    if objLink.to_socket.name == 'Factor':
                        objNodeTree.links.new(objLink.from_socket, objNewNode.inputs[0])
                    elif objLink.to_socket.name == 'A':
                        objNodeTree.links.new(objLink.from_socket, objNewNode.inputs[1])
                    elif objLink.to_socket.name == 'B':
                        objNodeTree.links.new(objLink.from_socket, objNewNode.inputs[2])
                    # disconnect from the old one
                    objNodeTree.links.remove(objLink)
            # GTFO!
            objNodeTree.nodes.remove(objNode)
    return

for objMaterial in bpy.data.materials:
    if objMaterial.node_tree:
        changeNodes(objMaterial.node_tree)