Bookmarks disappeared

[tompetrocelli]

Description:
I emptied the trash can and bookmarks stored in a different folder all disappeared.
I have been collecting bookmarks in a various folder for several months. I had 5 bookmarks in the trash bin. I clicked the "Empty Trash Bin" and it not only emptied the trash bin but the last folder in my list of folders. That has about 20 bookmarked urls in it.

Bookmark app is 16.2.1

Server
Ubuntu 26.04

OS: Ubuntu 26.04 resolute
Kernel: x86_64 Linux 7.0.0-22-generic
Disk: 275G / 1.4T (21%)
CPU: Intel Core i7-3770 @ 8x 3.9GHz [36.0°C]
GPU: HD Graphics 4000
RAM: 2810MiB / 7339MiB

Nextcloud Instance
33.0.5snap2, Snap package
Nextcloud Hub 26 Winter (33.0.5)

[github-actions]

Hello 👋

Thank you for taking the time to open this issue with the bookmarks app. I know it's frustrating when software
causes problems. You have made the right choice to come here and open an issue to make sure your problem gets looked at
and if possible solved.
I'm Marcel and have been maintaining this software the last few years. I currently work for Nextcloud but maintain this app
in my free time, because it is not an official Nextcloud product. My day job at Nextcloud is pretty awesome but sadly leaves me with
less time for side projects like this one than I used to have.
I still try to answer all issues and if possible fix all bugs here, but it sometimes takes a while until I get to it.
Until then, please be patient.
Note also that GitHub is a place where people meet to make software better together. Nobody here is under any obligation
to help you, solve your problems or deliver on any expectations or demands you may have, but if enough people come together we can
collaborate to make this software better. For everyone.
Thus, if you can, you could also look at other issues to see whether you can help other people with your knowledge
and experience. If you have coding experience it would also be awesome if you could step up to dive into the code and
try to fix the odd bug yourself. Everyone will be thankful for extra helping hands!
One last word: If you feel, at any point, like you need to vent, this is not the place for it; you can go to the forum,
to twitter or somewhere else. But this is a technical issue tracker, so please make sure to
focus on the tech and keep your opinions to yourself. (Also see our Code of Conduct. Really.)

I look forward to working with you on this issue
Cheers 💙

[marcelklehr]

Hello @tompetrocelli
Thank you for taking the time to give feedback by opening this issue!
This is an unfortunate outcome. It's unclear to me at the moment how this might have happened.
One possibility is that the app was in a limbo state: Maybe you had been viewing the folder that was later cleared erroneously, then switched to the trashbin and clicked the empty button while the app somehow still had the bookmarks from the folder in its internal state :S
I have recently improved the trashbin emptying procedure somewhat, in that it does not depend on internal state of the frontend anymore, but this work has not been released yet.
If you have enabled the backup functionality in the bookmarks settings you should be able to find those bookmarks again. The same goes for database backups, although it might be a bit trickier to get the urls from there. If you need help, I'm happy to answer questions. 💙

[tompetrocelli]

I was able to recover the bookmarks from the Android app. Basically, I didn't sync it, reloaded the URLs and resaved them. I could later move them to the folder I wanted them to be in. The folder it emptied was all in the last folder - other folders weren't touched. I'm assuming a "folder" is just a field in a database. Perhaps the DELETE to the database picked up the last folder as well. I'm guessing that's not all that helpful.

[tompetrocelli]

This may be helpful. Items in my trash bin are also showing up as duplicates in my folder. This points to the Move function not operating correctly. It looks like Move is first making a copy in a folder (adding the new folder to the record?) and then "moving" it into the trash bin at the same time. It now exists in both the trash bin and the folder I moved it to. Kind of a Schrödinger's record, being in both states at the same time. Empty the trash bin and the actual record is deleted, taking with it the one that was "in" the folder.

That's the only thing I can think of.

[marcelklehr]

@tompetrocelli Interesting! I'm not sure I completely follow, though. Could you perhaps write down, step by step, what you did and what the outcome was?

[tompetrocelli]

Sure.

1. Bookmark a website from the Chrome extension.
2. It shows up as a Bookmark in the All Bookmarks View
3. Select and move it to a folder.
4. The bookmark disappears from the All Bookmarks view
5. The bookmark is now in the designated folder. It is also in the Trash bin.
6. Go to the Trash Bin. See a message that says "One bookmark can be in multiple folders at once. Updating it will update all copies. All duplicated bookmarks are listed here for convenience." and you see the bookmarks you just moved.
7. Empty the Trash Bin and all copies of the bookmark disappear including the one's in the folder.

As long as I don't move the bookmarks to a folder, it's fine. If I move them to a folder, the app gets confused. If I moved the bookmarks before the last update, they seem fine. I tried this too:

1. Open a serious of bookmarks from the app
2. Delete the bookmarks that are in the folder
3. Intentionally empty the trash bin and removing the bookmarks "Permanently"
4. Reclip the bookmarks from the Chrome extension. Same URL but different metadata such as the title.
5. Bookmarks now appear in the All Bookmarks view and in the original folder from whence it was deleted.
6. They now show up in Duplicates as having multiple locations.

As far as I can see, you can have bookmarks in multiple folders. Move seems to "move" a bookmark to the folder then try to delete it from the All Bookmarks view. That creates a bookmark record that is "in" the folder and trash bin. I haven't looked at the code, but I assume that folders are rows in a database table and that you create a row in another table that includes a reference to the folder and a reference to the single bookmark row. To "move" a bookmark you create a new row with the folder id and delete the original, in this case the row with the root All Bookmarks folder id.
When you delete a bookmark, you create a record with the folder id of the Trash Bin. and remove the original folder record. Until you empty the trash bin, you don't actually delete a bookmark's row.
A couple of things seem to be happening here, but all are related to the whatever table you store folder associations in. Most likely, instead of deleting the row with the original folder id, you are using the same delete function that you use to eliminate bookmarks. because there is already an association between the new folder and the bookmark, and multiple associations are allowed, you end up creating a Trash Bin folder row and a new Folder Row thereby creating the Schrödinger's Bookmark. It is both in a folder (alive) and in the trash bin (dead) at the same time.
I admit that this is heavily speculative. All I can say for sure is what are int he two lists above.

Hope that helps.

[marcelklehr]

Yes, that makes sense. I could replicate the behavior and fix it. Thank you for taking the time to report this! 💙