From 22635b708b7bef4bebea4a97e271152bbdaa3a47 Mon Sep 17 00:00:00 2001
From: czlonkowski <czlonkowski@gmail.com>
Date: Fri, 27 Mar 2026 18:45:03 +0100
Subject: [PATCH] =?UTF-8?q?refactor:=20deduplicate=20tryParseJson=20?=
 =?UTF-8?q?=E2=80=94=20export=20from=20handlers-n8n-manager?=
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tryParseJson was duplicated in handlers-workflow-diff.ts. Now imported
from handlers-n8n-manager.ts where it was already defined. Updated
test mock to use importOriginal so the real function is available.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 src/mcp/handlers-n8n-manager.ts               |  2 +-
 src/mcp/handlers-workflow-diff.ts             |  8 +-------
 tests/unit/mcp/handlers-workflow-diff.test.ts | 10 +++++++---
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/src/mcp/handlers-n8n-manager.ts b/src/mcp/handlers-n8n-manager.ts
index b0761f1..5075e97 100644
--- a/src/mcp/handlers-n8n-manager.ts
+++ b/src/mcp/handlers-n8n-manager.ts
@@ -2731,7 +2731,7 @@ const updateTableSchema = tableIdSchema.extend({
 
 // MCP transports may serialize JSON objects/arrays as strings.
 // Parse them back, but return the original value on failure so Zod reports a proper type error.
-function tryParseJson(val: unknown): unknown {
+export function tryParseJson(val: unknown): unknown {
   if (typeof val !== 'string') return val;
   try { return JSON.parse(val); } catch { return val; }
 }
diff --git a/src/mcp/handlers-workflow-diff.ts b/src/mcp/handlers-workflow-diff.ts
index 1b36829..d5a8dc6 100644
--- a/src/mcp/handlers-workflow-diff.ts
+++ b/src/mcp/handlers-workflow-diff.ts
@@ -7,7 +7,7 @@ import { z } from 'zod';
 import { McpToolResponse } from '../types/n8n-api';
 import { WorkflowDiffRequest, WorkflowDiffOperation, WorkflowDiffValidationError } from '../types/workflow-diff';
 import { WorkflowDiffEngine } from '../services/workflow-diff-engine';
-import { getN8nApiClient } from './handlers-n8n-manager';
+import { getN8nApiClient, tryParseJson } from './handlers-n8n-manager';
 import { N8nApiError, getUserFriendlyErrorMessage } from '../utils/n8n-errors';
 import { logger } from '../utils/logger';
 import { InstanceContext } from '../types/instance-context';
@@ -36,12 +36,6 @@ const NODE_TARGETING_OPERATIONS = new Set([
   'updateNode', 'removeNode', 'moveNode', 'enableNode', 'disableNode'
 ]);
 
-// Parse JSON strings to values — VS Code extension sends arrays as JSON strings (#600)
-function tryParseJson(val: unknown): unknown {
-  if (typeof val !== 'string') return val;
-  try { return JSON.parse(val); } catch { return val; }
-}
-
 // Zod schema for the diff request
 const workflowDiffSchema = z.object({
   id: z.string(),
diff --git a/tests/unit/mcp/handlers-workflow-diff.test.ts b/tests/unit/mcp/handlers-workflow-diff.test.ts
index 11b844c..74faea7 100644
--- a/tests/unit/mcp/handlers-workflow-diff.test.ts
+++ b/tests/unit/mcp/handlers-workflow-diff.test.ts
@@ -17,9 +17,13 @@ vi.mock('@/services/workflow-diff-engine');
 vi.mock('@/services/n8n-api-client');
 vi.mock('@/config/n8n-api');
 vi.mock('@/utils/logger');
-vi.mock('@/mcp/handlers-n8n-manager', () => ({
-  getN8nApiClient: vi.fn(),
-}));
+vi.mock('@/mcp/handlers-n8n-manager', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('@/mcp/handlers-n8n-manager')>();
+  return {
+    ...actual,
+    getN8nApiClient: vi.fn(),
+  };
+});
 
 // Import mocked modules
 import { getN8nApiClient } from '@/mcp/handlers-n8n-manager';