Fix migration to only use existing version ids

Author: dariacodes

packages/@n8n/db/src/migrations/common/1761302979000-AddActiveVersionIdColumn.ts

@@ -22,8 +22,22 @@ export class AddActiveVersionIdColumn1761302979000 implements ReversibleMigratio
 		);
 
 		// For existing ACTIVE workflows, set activeVersionId = versionId
+		// Only update workflows where the versionId exists in workflow_history to avoid
+		// foreign key constraint violations. Some users don't have workflow history enabled,
+		// and their workflows need to have activeVersionId = NULL until we enable history for them.
+		const workflowHistoryTableName = escape.tableName(WORKFLOW_HISTORY_TABLE_NAME);
+		const versionIdColumn = escape.columnName('versionId');
+		const activeColumn = escape.columnName('active');
+		const activeVersionIdColumn = escape.columnName('activeVersionId');
+
 		await queryRunner.query(
-			`UPDATE ${workflowsTableName} SET activeVersionId = versionId WHERE active = true`,
+			`UPDATE ${workflowsTableName}
+			 SET ${activeVersionIdColumn} = ${versionIdColumn}
+			 WHERE ${activeColumn} = true
+			 AND EXISTS (
+			 	SELECT 1 FROM ${workflowHistoryTableName}
+			 	WHERE ${workflowHistoryTableName}.${versionIdColumn} = ${workflowsTableName}.${versionIdColumn}
+			 )`,
 		);
 	}