Node deletion with multiple links connected to same output throws an "Item not found" error.

[marklinmax]

Version of Dear PyGui

Version: 2.0.0 Operating System: macOS 15.1.1

My Issue/Question

Deleting a node with multiple links connected to a single of its outputs leads to "Item not found" error on some link ids.

Error message:

Exception: 
Error:     [1005]
Command:   delete_item
Item:      0 
Label:     Not found
Item Type: Unknown
Message:   Item not found: 40

To Reproduce

Create two nodes with multiple inputs / outputs. Connect single output of first node to multiple inputs of second node. Delete first node. => Item not found error.

Expected behavior

Should delete all links cleanly.

Standalone, minimal, complete and verifiable example

import dearpygui.dearpygui as dpg
dpg.create_context()

def link_callback(sender, links):
    dpg.add_node_link(links[0], links[1], parent=sender)

def delink_callback(sender, link):
    dpg.delete_item(link)

def delNodes(sender):
     lst = dpg.get_selected_nodes("node_edit")
     for node in lst:
        dpg.delete_item(node)

with dpg.window(tag="window", label="Del node bug", width=400, height=400):
    dpg.add_menu_item(label="Delete", callback=delNodes)
    with dpg.node_editor(parent="window", tag="node_edit", callback=link_callback, delink_callback=delink_callback):

        with dpg.node(tag=2000, label="Node 1"):
            with dpg.node_attribute(tag=100, label="s1", attribute_type=dpg.mvNode_Attr_Input):
                dpg.add_text("intextonly")
            with dpg.node_attribute(tag=200, label="s2", attribute_type=dpg.mvNode_Attr_Output):
                dpg.add_text("outtextonly")
            with dpg.node_attribute(label="s2", attribute_type=dpg.mvNode_Attr_Output):
                dpg.add_text("outtextonly")
            with dpg.node_attribute(tag=300, label="s3", attribute_type=dpg.mvNode_Attr_Output):
                dpg.add_text("outextonly")

        with dpg.node(tag=3000, label="Node 2"):
            with dpg.node_attribute(tag=400, label="s1", attribute_type=dpg.mvNode_Attr_Input):
                dpg.add_text("intextonly")
            with dpg.node_attribute(tag=500, label="s2", attribute_type=dpg.mvNode_Attr_Input):
                dpg.add_text("intextonly")
            with dpg.node_attribute(label="s2", attribute_type=dpg.mvNode_Attr_Input):
                dpg.add_text("intextonly")
            with dpg.node_attribute(label="s2", attribute_type=dpg.mvNode_Attr_Input):
                dpg.add_text("intextonly")
            with dpg.node_attribute(tag=600, label="s3", attribute_type=dpg.mvNode_Attr_Output):
                dpg.add_text("outtextonly")


dpg.create_viewport(title='Del node bug', width=800, height=600)
dpg.setup_dearpygui()
dpg.show_viewport()
dpg.set_primary_window("window", True)
dpg.start_dearpygui()
dpg.destroy_context()

[v-ein]

Good catch! Looks like a bug in mvNodeEditor::onChildRemoved: the function is trying to remove node links while it is iterating over the list of those node links :joy: (childslots[0]). It also makes an unnecessary call to CleanUpItem, so whoever goes ahead and fixes this, please remove the call.

A workaround would be to manually remove all the links tied to the node being deleted.