invoke-ai/InvokeAI · error · InvalidEdgeError

Invalid collector node ({node.id}): {err}

Error message

Invalid collector node ({node.id}): {err}

What it means

InvalidEdgeError raised in validate_self() for each CollectInvocation whose connections fail _is_collector_connection_valid(). A collector aggregates 'item'-typed edges into a collection, so all incoming edges must have the same type; the checker's err string is embedded in the message.

Source

Thrown at invokeai/app/services/shared/graph.py:1860

            if not are_connections_compatible(
                self.get_node(edge.source.node_id),
                edge.source.field,
                destination_node,
                edge.destination.field,
            ):
                raise InvalidEdgeError(f"Edge source and target types do not match ({edge})")

    def _validate_special_nodes(self) -> None:
        # TODO: may need to validate all iterators & collectors in subgraphs so edge connections in parent graphs will be available
        for node in self.nodes.values():
            if isinstance(node, IterateInvocation):
                err = self._is_iterator_connection_valid(node.id)
                if err is not None:
                    raise InvalidEdgeError(f"Invalid iterator node ({node.id}): {err}")
            if isinstance(node, CollectInvocation):
                err = self._is_collector_connection_valid(node.id)
                if err is not None:
                    raise InvalidEdgeError(f"Invalid collector node ({node.id}): {err}")

    def validate_self(self) -> None:
        """
        Validates the graph.

        Raises an exception if the graph is invalid:
        - `DuplicateNodeIdError`
        - `NodeIdMismatchError`
        - `InvalidSubGraphError`
        - `NodeNotFoundError`
        - `NodeFieldNotFoundError`
        - `CyclicalGraphError`
        - `InvalidEdgeError`
        """

        self._validate_unique_node_ids()
        self._validate_node_id_mapping()
        self._validate_edge_nodes_and_fields()

View on GitHub (pinned to 0b6a024f2f)

Solutions

1. Make every edge into the collector's 'item' field carry the same type
2. Split heterogeneous outputs into separate collectors
3. Add conversion nodes so all inputs share one type
4. Remove stale edges after refactoring the graph

Example fix

// before
g.add_edge(image_node, "image", collector, "item")
g.add_edge(prompt_node, "prompt", collector, "item")  # mixed types
// after
g.add_edge(img_a, "image", collector, "item")
g.add_edge(img_b, "image", collector, "item")

def collector_inputs_ok(graph, collect_node_id):
    return graph._is_collector_connection_valid(collect_node_id) is None

for node_id in g.nodes:
    if isinstance(g.get_node(node_id), CollectInvocation):
        assert collector_inputs_ok(g, node_id), node_id

def is_valid_collector(graph, node) -> bool:
    if not isinstance(node, CollectInvocation):
        return False
    return graph._is_collector_connection_valid(node.id) is None

from invokeai.app.services.shared.graph import InvalidEdgeError

try:
    graph.validate_self()
except InvalidEdgeError as e:
    if "Invalid collector node" in str(e):
        fix_collector_connections(e)
    raise

When it happens

Trigger: validate_self() encountering a CollectInvocation with incoming item edges of differing/incompatible types, or malformed connections to its 'item'/'collection' fields (via _is_collector_connection_valid).

Common situations: Collecting outputs of heterogeneous nodes (image + string) into one collector, iterating a collection and feeding differently-typed branches into the same collector, hand-edited workflow JSON.

Related errors

• Invalid iterator node ({node.id}): {err}
• The selected saved workflow must contain exactly one workflo
• Graph contains cycles
• Edge source and target types do not match ({edge})
• Problem validating graph {e}

AI-assisted analysis of invoke-ai/InvokeAI@0b6a024f2f (2026-08-29). Data as JSON: /api/errors/92f81ed9793b2408. Report an issue: GitHub.