feat(core): Support executing single nodes not part of a graph as a partial execution (#13529)

packages/core/src/execution-engine/partial-execution-utils/__tests__/find-subgraph.test.ts

@@ -33,6 +33,27 @@ describe('findSubgraph', () => {
 		expect(subgraph).toEqual(graph);
 	});
 
+	//                 ►►
+	//                ┌──────┐
+	//                │orphan│
+	//                └──────┘
+	//  ┌───────┐     ┌───────────┐
+	//  │trigger├────►│destination│
+	//  └───────┘     └───────────┘
+	test('works with a single node', () => {
+		const trigger = createNodeData({ name: 'trigger' });
+		const destination = createNodeData({ name: 'destination' });
+		const orphan = createNodeData({ name: 'orphan' });
+
+		const graph = new DirectedGraph()
+			.addNodes(trigger, destination, orphan)
+			.addConnections({ from: trigger, to: destination });
+
+		const subgraph = findSubgraph({ graph, destination: orphan, trigger: orphan });
+
+		expect(subgraph).toEqual(new DirectedGraph().addNode(orphan));
+	});
+
 	//                     ►►
 	//  ┌───────┐         ┌───────────┐
 	//  │       ├────────►│           │

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

@@ -13,6 +13,12 @@ function findSubgraphRecursive(
 ) {
 	// If the current node is the chosen trigger keep this branch.
 	if (current === trigger) {
+		// If this graph consists of only one node there won't be any connections
+		// and the loop below won't add anything.
+		// We're adding the trigger here so that graphs with one node and no
+		// connections are handled correctly.
+		newGraph.addNode(trigger);
+
 		for (const connection of currentBranch) {
 			newGraph.addNodes(connection.from, connection.to);
 			newGraph.addConnection(connection);