refactor(core): Reorganize n8n-core and enforce file-name casing (no-changelog) (#12667)

packages/core/src/execution-engine/partial-execution-utils/find-start-nodes.ts

@@ -0,0 +1,176 @@
+import { NodeConnectionType, type INode, type IPinData, type IRunData } from 'n8n-workflow';
+
+import type { DirectedGraph } from './directed-graph';
+import { getIncomingData, getIncomingDataFromAnyRun } from './get-incoming-data';
+
+/**
+ * A node is dirty if either of the following is true:
+ *   - it's properties or options changed since last execution (not implemented yet)
+ *   - one of it's parents is disabled
+ *   - it has an error (not implemented yet)
+ *   - it neither has run data nor pinned data
+ */
+export function isDirty(node: INode, runData: IRunData = {}, pinData: IPinData = {}): boolean {
+	// TODO: implement
+	const propertiesOrOptionsChanged = false;
+
+	if (propertiesOrOptionsChanged) {
+		return true;
+	}
+
+	// TODO: implement
+	const parentNodeGotDisabled = false;
+
+	if (parentNodeGotDisabled) {
+		return true;
+	}
+
+	// TODO: implement
+	const hasAnError = false;
+
+	if (hasAnError) {
+		return true;
+	}
+
+	const hasPinnedData = pinData[node.name] !== undefined;
+
+	if (hasPinnedData) {
+		return false;
+	}
+
+	const hasRunData = runData?.[node.name];
+
+	if (hasRunData) {
+		return false;
+	}
+
+	return true;
+}
+
+function findStartNodesRecursive(
+	graph: DirectedGraph,
+	current: INode,
+	destination: INode,
+	runData: IRunData,
+	pinData: IPinData,
+	startNodes: Set<INode>,
+	seen: Set<INode>,
+): Set<INode> {
+	const nodeIsDirty = isDirty(current, runData, pinData);
+
+	// If the current node is dirty stop following this branch, we found a start
+	// node.
+	if (nodeIsDirty) {
+		startNodes.add(current);
+
+		return startNodes;
+	}
+
+	// If the current node is the destination node stop following this branch, we
+	// found a start node.
+	if (current === destination) {
+		startNodes.add(current);
+		return startNodes;
+	}
+
+	// If the current node is a loop node, check if the `done` output has data on
+	// the last run. If it doesn't the loop wasn't fully executed and needs to be
+	// re-run from the start. Thus the loop node become the start node.
+	if (current.type === 'n8n-nodes-base.splitInBatches') {
+		const nodeRunData = getIncomingData(
+			runData,
+			current.name,
+			// last run
+			-1,
+			NodeConnectionType.Main,
+			0,
+		);
+
+		if (nodeRunData === null || nodeRunData.length === 0) {
+			startNodes.add(current);
+			return startNodes;
+		}
+	}
+
+	// If we detect a cycle stop following the branch, there is no start node on
+	// this branch.
+	if (seen.has(current)) {
+		return startNodes;
+	}
+
+	// Recurse with every direct child that is part of the sub graph.
+	const outGoingConnections = graph.getDirectChildConnections(current);
+	for (const outGoingConnection of outGoingConnections) {
+		const nodeRunData = getIncomingDataFromAnyRun(
+			runData,
+			outGoingConnection.from.name,
+			outGoingConnection.type,
+			outGoingConnection.outputIndex,
+		);
+
+		// If the node has multiple outputs, only follow the outputs that have run data.
+		const hasNoRunData =
+			nodeRunData === null || nodeRunData === undefined || nodeRunData.data.length === 0;
+		if (hasNoRunData) {
+			continue;
+		}
+
+		findStartNodesRecursive(
+			graph,
+			outGoingConnection.to,
+			destination,
+			runData,
+			pinData,
+			startNodes,
+			new Set(seen).add(current),
+		);
+	}
+
+	return startNodes;
+}
+
+/**
+ * The start node is the node from which a partial execution starts. The start
+ * node will be executed or re-executed.
+ * The nodes are found by traversing the graph from the trigger to the
+ * destination and finding the earliest dirty nodes on every branch.
+ *
+ * The algorithm is:
+ *  Starting from the trigger node.
+ *
+ * 	1. if the current node is not a trigger and has no input data (on all
+ * 	   connections) (not implemented yet, possibly not necessary)
+ * 	  - stop following this branch, there is no start node on this branch
+ * 	2. If the current node is dirty, or is the destination node
+ * 	  - stop following this branch, we found a start node
+ * 	3. If we detect a cycle
+ * 	  - stop following the branch, there is no start node on this branch
+ * 	4. Recurse with every direct child that is part of the sub graph
+ */
+export function findStartNodes(options: {
+	graph: DirectedGraph;
+	trigger: INode;
+	destination: INode;
+	pinData: IPinData;
+	runData: IRunData;
+}): Set<INode> {
+	const graph = options.graph;
+	const trigger = options.trigger;
+	const destination = options.destination;
+	const runData = { ...options.runData };
+	const pinData = options.pinData;
+
+	const startNodes = findStartNodesRecursive(
+		graph,
+		trigger,
+		destination,
+		runData,
+		pinData,
+		// start nodes found
+		new Set(),
+		// seen
+		new Set(),
+	);
+
+	return startNodes;
+}