From d8620ab9d40ba73dc621a99813c288d35ee29d12 Mon Sep 17 00:00:00 2001
From: Mr-KRAMA <khanderam4@gmail.com>
Date: Wed, 3 Dec 2025 15:13:14 +0530
Subject: [PATCH] fix: prevent Remove Duplicates node from discarding new RSS
 items

---
 .../src/deduplication/deduplication-helper.ts |   7 +-
 .../remove-duplicates-rss.test.ts             | 113 ++++++++++++++++++
 2 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 packages/cli/test/integration/deduplication/remove-duplicates-rss.test.ts

diff --git a/packages/cli/src/deduplication/deduplication-helper.ts b/packages/cli/src/deduplication/deduplication-helper.ts
index 1b30d9bfbf1..6ca2b6711f5 100644
--- a/packages/cli/src/deduplication/deduplication-helper.ts
+++ b/packages/cli/src/deduplication/deduplication-helper.ts
@@ -235,15 +235,20 @@ export class DeduplicationHelper implements IDataDeduplicator {
 		const processedDataValue = processedData.value;
 		const processedItemsSet = new Set(processedDataValue.data);
 
+		const newHashedItems: string[] = [];
+
 		hashedItems.forEach((item, index) => {
 			if (processedItemsSet.has(item)) {
 				returnData.processed.push(items[index]);
 			} else {
 				returnData.new.push(items[index]);
-				processedDataValue.data.push(item);
+				newHashedItems.push(item);
 			}
 		});
 
+		// Only add new items to processed data after processing all items
+		processedDataValue.data.push(...newHashedItems);
+
 		if (options.maxEntries) {
 			processedDataValue.data.splice(0, processedDataValue.data.length - options.maxEntries);
 		}
diff --git a/packages/cli/test/integration/deduplication/remove-duplicates-rss.test.ts b/packages/cli/test/integration/deduplication/remove-duplicates-rss.test.ts
new file mode 100644
index 00000000000..59bf984b7b4
--- /dev/null
+++ b/packages/cli/test/integration/deduplication/remove-duplicates-rss.test.ts
@@ -0,0 +1,113 @@
+import { DeduplicationHelper } from '@/deduplication/deduplication-helper';
+import type { ICheckProcessedContextData, ICheckProcessedOptions } from 'n8n-workflow';
+
+describe('Remove Duplicates RSS Feed Bug', () => {
+	let deduplicationHelper: DeduplicationHelper;
+	let contextData: ICheckProcessedContextData;
+	let options: ICheckProcessedOptions;
+
+	beforeEach(() => {
+		deduplicationHelper = new DeduplicationHelper();
+		contextData = {
+			workflow: { id: 'test-workflow-id' },
+			node: { id: 'test-node-id', name: 'Remove Duplicates', type: 'removeDuplicates' },
+		} as any;
+		options = {
+			mode: 'entries',
+			maxEntries: 1000,
+		};
+	});
+
+	it('should not discard all items on subsequent RSS feed runs', async () => {
+		// Simulate first RSS feed run with 3 items
+		const firstRunItems = ['item1', 'item2', 'item3'];
+
+		const firstResult = await deduplicationHelper.checkProcessedAndRecord(
+			firstRunItems,
+			'node',
+			contextData,
+			options,
+		);
+
+		// First run: all items should be new
+		expect(firstResult.new).toHaveLength(3);
+		expect(firstResult.processed).toHaveLength(0);
+
+		// Simulate second RSS feed run with 2 existing + 2 new items
+		const secondRunItems = ['item2', 'item3', 'item4', 'item5'];
+
+		const secondResult = await deduplicationHelper.checkProcessedAndRecord(
+			secondRunItems,
+			'node',
+			contextData,
+			options,
+		);
+
+		// Second run: should have 2 new items, 2 processed
+		expect(secondResult.new).toHaveLength(2);
+		expect(secondResult.new).toEqual(['item4', 'item5']);
+		expect(secondResult.processed).toHaveLength(2);
+		expect(secondResult.processed).toEqual(['item2', 'item3']);
+
+		// Simulate third RSS feed run with 1 existing + 1 new item
+		const thirdRunItems = ['item5', 'item6'];
+
+		const thirdResult = await deduplicationHelper.checkProcessedAndRecord(
+			thirdRunItems,
+			'node',
+			contextData,
+			options,
+		);
+
+		// Third run: should have 1 new item, 1 processed
+		expect(thirdResult.new).toHaveLength(1);
+		expect(thirdResult.new).toEqual(['item6']);
+		expect(thirdResult.processed).toHaveLength(1);
+		expect(thirdResult.processed).toEqual(['item5']);
+	});
+
+	it('should handle RSS feed with all new items correctly', async () => {
+		// First run
+		const firstResult = await deduplicationHelper.checkProcessedAndRecord(
+			['rss1', 'rss2'],
+			'node',
+			contextData,
+			options,
+		);
+
+		expect(firstResult.new).toEqual(['rss1', 'rss2']);
+		expect(firstResult.processed).toEqual([]);
+
+		// Second run with completely new items
+		const secondResult = await deduplicationHelper.checkProcessedAndRecord(
+			['rss3', 'rss4'],
+			'node',
+			contextData,
+			options,
+		);
+
+		expect(secondResult.new).toEqual(['rss3', 'rss4']);
+		expect(secondResult.processed).toEqual([]);
+	});
+
+	it('should handle RSS feed with all duplicate items correctly', async () => {
+		// First run
+		await deduplicationHelper.checkProcessedAndRecord(
+			['dup1', 'dup2', 'dup3'],
+			'node',
+			contextData,
+			options,
+		);
+
+		// Second run with same items
+		const result = await deduplicationHelper.checkProcessedAndRecord(
+			['dup1', 'dup2', 'dup3'],
+			'node',
+			contextData,
+			options,
+		);
+
+		expect(result.new).toEqual([]);
+		expect(result.processed).toEqual(['dup1', 'dup2', 'dup3']);
+	});
+});