From ed8ca1bfce69eb9e57b12eb363e81719d5607793 Mon Sep 17 00:00:00 2001
From: Abe Jellinek <1770299+AbeJellinek@users.noreply.github.com>
Date: Wed, 23 Sep 2026 13:53:08 -0400
Subject: [PATCH] Item merging: Don't merge web link attachments with different
 URLs

https://forums.zotero.org/discussion/133795
---
 chrome/content/zotero/mergeItems.mjs |  6 ++++--
 test/tests/mergeItemsTest.js         | 27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/chrome/content/zotero/mergeItems.mjs b/chrome/content/zotero/mergeItems.mjs
index 496b4dd844..0b1f6df09e 100644
--- a/chrome/content/zotero/mergeItems.mjs
+++ b/chrome/content/zotero/mergeItems.mjs
@@ -240,12 +240,14 @@ async function mergeWebAttachments(item, otherItems) {
 			}
 
 			// If we can find an attachment with the same title *and* URL, use it.
+			// For snapshots, fall back to matching on title alone.
 			let masterAttachment = (
 				masterAttachments.find(attachment => attachment.getField('title') == otherAttachment.getField('title')
 					&& attachment.getField('url') == otherAttachment.getField('url')
 					&& attachment.attachmentLinkMode === otherAttachment.attachmentLinkMode)
-				|| masterAttachments.find(attachment => attachment.getField('title') == otherAttachment.getField('title')
-					&& attachment.attachmentLinkMode === otherAttachment.attachmentLinkMode)
+				|| otherAttachment.attachmentLinkMode !== Zotero.Attachments.LINK_MODE_LINKED_URL
+					&& masterAttachments.find(attachment => attachment.getField('title') == otherAttachment.getField('title')
+						&& attachment.attachmentLinkMode === otherAttachment.attachmentLinkMode)
 			);
 
 			if (!masterAttachment) {
diff --git a/test/tests/mergeItemsTest.js b/test/tests/mergeItemsTest.js
index 6867e2f0eb..a46936b5ba 100644
--- a/test/tests/mergeItemsTest.js
+++ b/test/tests/mergeItemsTest.js
@@ -573,6 +573,33 @@ describe("Item merging", function () {
 		assert.isFalse(attachment3.deleted);
 	});
 
+	it("should keep linked URL with same title but different URL", async function () {
+		let item1 = await createDataObject('item', { setTitle: true });
+		let attachment1 = await Zotero.Attachments.linkFromURL({
+			url: 'https://example.com/',
+			title: 'Catalog Entry',
+			parentItemID: item1.id
+		});
+
+		let item2 = item1.clone();
+		await item2.saveTx();
+		let attachment2 = await Zotero.Attachments.linkFromURL({
+			url: 'https://otherdomain.example.com/',
+			title: 'Catalog Entry',
+			parentItemID: item2.id
+		});
+
+		await mergeItems(item1, [item2]);
+
+		assert.isFalse(item1.deleted);
+		assert.isFalse(attachment1.deleted);
+		assert.equal(item1.numAttachments(true), 2);
+		assert.isTrue(item2.deleted);
+		assert.equal(attachment2.parentItemID, item1.id);
+		assert.isFalse(attachment2.deleted);
+		assert.equal(attachment2.getField('url'), 'https://otherdomain.example.com/');
+	});
+
 	it("should keep web attachment with same URL but different title", async function () {
 		let item1 = await createDataObject('item', { setTitle: true });
 		let attachment1 = await Zotero.Attachments.linkFromURL({