From 5bceea7b7b6b53934f028b9bb0848c1936912e72 Mon Sep 17 00:00:00 2001
From: Dan Stillman <dstillman@zotero.org>
Date: Mon, 23 Mar 2026 10:23:11 -0400
Subject: [PATCH] Fix Added By backfill skipping items when batch count doesn't
 change

Use itemID offset to advance through batches instead of comparing
result counts, which would bail out when the number of remaining items
equaled the previous batch size.
---
 .../content/zotero/xpcom/sync/syncEngine.js   | 22 ++++++++-----------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/chrome/content/zotero/xpcom/sync/syncEngine.js b/chrome/content/zotero/xpcom/sync/syncEngine.js
index f1cce4b106..a5f20a8db3 100644
--- a/chrome/content/zotero/xpcom/sync/syncEngine.js
+++ b/chrome/content/zotero/xpcom/sync/syncEngine.js
@@ -1510,8 +1510,9 @@ Zotero.Sync.Data.Engine.prototype._updateGroupItemUsers = async function () {
 	let max = this.apiClient.MAX_OBJECTS_PER_REQUEST;
 	let sql = "SELECT key FROM items LEFT JOIN groupItems GI USING (itemID) "
 		+ "WHERE libraryID=? AND (GI.itemID IS NULL OR GI.createdByUserID IS NULL) "
-		+ `ORDER BY itemID LIMIT ${max}`;
-	let keys = await Zotero.DB.columnQueryAsync(sql, this.libraryID);
+		+ `AND items.itemID > ? ORDER BY items.itemID LIMIT ${max}`;
+	let minItemID = 0;
+	let keys = await Zotero.DB.columnQueryAsync(sql, [this.libraryID, minItemID]);
 	if (!keys.length) {
 		await Zotero.DB.queryAsync(
 			"REPLACE INTO settings VALUES ('sync', ?, 1)",
@@ -1523,16 +1524,7 @@ Zotero.Sync.Data.Engine.prototype._updateGroupItemUsers = async function () {
 	Zotero.debug(`Updating item users in ${this.library.name}`);
 
 	let updatedItemIDs = [];
-	let lastCount;
 	while (keys.length) {
-		// If no progress was made, some items can't be resolved -- mark
-		// as complete so we don't retry every sync
-		if (keys.length === lastCount) {
-			Zotero.debug(`${keys.length} items remaining without user data -- stopping`);
-			break;
-		}
-		lastCount = keys.length;
-
 		let { json: jsonItems, error } = await this.apiClient.downloadObjects(
 			this.library.libraryType, this.libraryTypeID, 'item', keys
 		)[0];
@@ -1550,7 +1542,6 @@ Zotero.Sync.Data.Engine.prototype._updateGroupItemUsers = async function () {
 			let item = Zotero.Items.getByLibraryAndKey(this.libraryID, jsonItem.key);
 			let params = [null, null];
 
-			// This should almost always exist, but maybe doesn't for some old items?
 			if (jsonItem.meta.createdByUser) {
 				let { id: userID, username, name } = jsonItem.meta.createdByUser;
 				await Zotero.Users.setName(userID, name !== '' ? name : username);
@@ -1567,7 +1558,12 @@ Zotero.Sync.Data.Engine.prototype._updateGroupItemUsers = async function () {
 			updatedItemIDs.push(item.id);
 		}
 
-		keys = await Zotero.DB.columnQueryAsync(sql, this.libraryID);
+		// Advance past this batch using the last key from the query
+		let lastItem = Zotero.Items.getByLibraryAndKey(
+			this.libraryID, keys[keys.length - 1]
+		);
+		minItemID = lastItem.id;
+		keys = await Zotero.DB.columnQueryAsync(sql, [this.libraryID, minItemID]);
 	}
 
 	await Zotero.DB.queryAsync("REPLACE INTO settings VALUES ('sync', ?, 1)", settingKey);