User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0 Build ID: 20171107091003 Steps to reproduce: 1. Add desktop and Android clients to a Firefox account, setting them both to sync bookmarks. 2. On the desktop client, open several pages in tabs, then right click a tab and select Bookmark All Tabs. 3. Click "Add Bookmarks," leaving the folder name as the default: "[Folder Name]" 3. Repeat 2 and 3 a few times with different sets of tabs. 4. Ensure that the desktop client is fully synced. 5. Open the Android client and wait for bookmarks to fully sync. Actual results: The contents of all the folders with the same name will be merged into a single folder. Then, this error is synced back, and the bookmarks on the desktop client will also be moved into the incorrect folder. Expected results: The contents of each folder should've stayed in the correct folder.

Note that this bug only occurs when a Firefox for Android client is participating in Sync. It never occurs when syncing to a desktop client. The bug also occurs on both Firefox for Android and Firefox Beta.

(In reply to Daniel from comment #1) > Note that this bug only occurs when a Firefox for Android client is > participating in Sync. It never occurs when syncing to a desktop client. Sadly, this is because Desktop and Android use slightly different algorithms to home children into folders. However, that logic shouldn't be happening here -- the full tree structure should be downloaded from the server. Grisha, would Daniel's first sync logs shed light on why we're doing content resolution instead of GUID chasing?

markh: I feel like there are Android and Desktop tickets tracking these differences. Can you crosslink for me?

I should clarify that I don't know if the bug occurred on the actual first sync to the mobile client. It may have only happened on subsequent sync attempts. That being said, even if it only happens on subsequent syncs, that still constitutes a bug, surely. If desktop and Android use sufficiently different algorithms that they corrupt each others' bookmark trees when they're on the same account, then either the Android sync logic should be changed to match the desktop clients, or they shouldn't be allowed to be joined to the same account.

(In reply to Daniel from comment #4) > I should clarify that I don't know if the bug occurred on the actual first > sync to the mobile client. It may have only happened on subsequent sync > attempts. > > That being said, even if it only happens on subsequent syncs, that still > constitutes a bug, surely. If desktop and Android use sufficiently > different algorithms that they corrupt each others' bookmark trees when > they're on the same account, then either the Android sync logic should be > changed to match the desktop clients, or they shouldn't be allowed to be > joined to the same account. Oh yeah, it's definitely a bug -- I'm just not sure where we think the issue lies. Is it Desktop's upload or Android's download and application? I think it's the latter, but I'm pretty far out of the loop here -- hence the requests to others for context.

Most likely an Android bug - we're doing the wrong thing while finding parents of records during bookmark insertion. There is a slew of similar bugs already, so I'll block this against a meta which is collecting them. https://bugzilla.mozilla.org/show_bug.cgi?id=1343365#c15 and onward has some related notes.

(In reply to Nick Alexander :nalexander from comment #3) > markh: I feel like there are Android and Desktop tickets tracking these > differences. Can you crosslink for me? As Grisha noted, but 1353641 is the appropriate meta.

Work to fix this is happening in Bug 1343365.