fix(editor): Prevent creation of input connections for nodes without input slot (#5425)

* fix(editor): Prevent creation of input connections for nodes without input

* WIP: Workflow checks service and controller

* fix: Created SQLite migration to remove broken connections

* Cleanup & add mysql/posgres migrations

* Linter fixes

* Unify the migration scripts

* Escape migration workflow_entity

* Wrap the migration in try/catch and do not parse nodes and connection if mysql/postgres

* Do migration changes also fro mysql

* refactor: Wrap only the necessary call in try catch block

---------

Co-authored-by: Omar Ajoue <krynble@gmail.com>

packages/cli/src/databases/migrations/postgresdb/1675940580449-PurgeInvalidWorkflowConnections.ts

@@ -0,0 +1,90 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+import { getTablePrefix, logMigrationEnd, logMigrationStart } from '@db/utils/migrationHelpers';
+import { NodeTypes } from '@/NodeTypes';
+import { IConnections, INode } from 'n8n-workflow';
+import { getLogger } from '@/Logger';
+export class PurgeInvalidWorkflowConnections1675940580449 implements MigrationInterface {
+	name = 'PurgeInvalidWorkflowConnections1675940580449';
+
+	async up(queryRunner: QueryRunner): Promise<void> {
+		logMigrationStart(this.name);
+
+		const tablePrefix = getTablePrefix();
+
+		const workflows: Array<{ id: number; nodes: INode[]; connections: IConnections }> =
+			await queryRunner.query(`
+			SELECT id, nodes, connections
+			FROM "${tablePrefix}workflow_entity"
+		`);
+
+		const nodeTypes = NodeTypes();
+
+		workflows.forEach(async (workflow) => {
+			let connections: IConnections = workflow.connections;
+			const nodes: INode[] = workflow.nodes;
+
+			const nodesThatCannotReceiveInput: string[] = nodes.reduce((acc, node) => {
+				try {
+					const nodeType = nodeTypes.getByNameAndVersion(node.type, node.typeVersion);
+					if ((nodeType.description.inputs?.length ?? []) === 0) {
+						acc.push(node.name);
+					}
+				} catch (error) {
+					getLogger().warn(`Migration ${this.name} failed with error: ${error.message}`);
+				}
+				return acc;
+			}, [] as string[]);
+
+			Object.keys(connections).forEach((sourceNodeName) => {
+				const connection = connections[sourceNodeName];
+				const outputs = Object.keys(connection);
+
+				outputs.forEach((outputConnectionName /* Like `main` */, idx) => {
+					const outputConnection = connection[outputConnectionName];
+
+					// It filters out all connections that are connected to a node that cannot receive input
+					outputConnection.forEach((outputConnectionItem, outputConnectionItemIdx) => {
+						outputConnection[outputConnectionItemIdx] = outputConnectionItem.filter(
+							(outgoingConnections) =>
+								!nodesThatCannotReceiveInput.includes(outgoingConnections.node),
+						);
+					});
+
+					// Filter out output connection items that are empty
+					connection[outputConnectionName] = connection[outputConnectionName].filter(
+						(item) => item.length > 0,
+					);
+
+					// Delete the output connection container if it is empty
+					if (connection[outputConnectionName].length === 0) {
+						delete connection[outputConnectionName];
+					}
+				});
+
+				// Finally delete the source node if it has no output connections
+				if (Object.keys(connection).length === 0) {
+					delete connections[sourceNodeName];
+				}
+			});
+
+			// Update database with new connections
+			const [updateQuery, updateParams] = queryRunner.connection.driver.escapeQueryWithParameters(
+				`
+						UPDATE "${tablePrefix}workflow_entity"
+						SET connections = :connections
+						WHERE id = '${workflow.id}'
+					`,
+				{ connections: JSON.stringify(connections) },
+				{},
+			);
+
+			await queryRunner.query(updateQuery, updateParams);
+		});
+
+		logMigrationEnd(this.name);
+	}
+
+	async down(queryRunner: QueryRunner): Promise<void> {
+		// No need to revert this migration
+	}
+}

packages/cli/src/databases/migrations/postgresdb/index.ts

@@ -28,6 +28,7 @@ import { RemoveWorkflowDataLoadedFlag1671726148421 } from './1671726148421-Remov
 import { MessageEventBusDestinations1671535397530 } from './1671535397530-MessageEventBusDestinations';
 import { DeleteExecutionsWithWorkflows1673268682475 } from './1673268682475-DeleteExecutionsWithWorkflows';
 import { CreateLdapEntities1674509946020 } from './1674509946020-CreateLdapEntities';
+import { PurgeInvalidWorkflowConnections1675940580449 } from './1675940580449-PurgeInvalidWorkflowConnections';
 
 export const postgresMigrations = [
 	InitialMigration1587669153312,
@@ -60,4 +61,5 @@ export const postgresMigrations = [
 	MessageEventBusDestinations1671535397530,
 	DeleteExecutionsWithWorkflows1673268682475,
 	CreateLdapEntities1674509946020,
+	PurgeInvalidWorkflowConnections1675940580449
 ];