The secret edit link points to the wrong map after a database restore.

[gislars]

After restoring a database backup, an edit link for an anonymous map may point to a different map if the original map no longer exists in the restored database and a new map has been assigned the same ID.

A user reported that a secret editing link sent by email no longer works and now points to a different map that the user did not create.

It happened on https://umap.openstreetmap.de which is running release 3.4.0

Steps to reproduce:

1. Create a DB backup.
2. Create an anonymous map.
3. Generate a secret editing link.
4. Restore the DB backup.
5. Create a new anonymous map (with the same ID).
6. Use the original secret editing link. Or compare the newly generated link with the original link, they are the same.
7. The link will point to the new map instead of the original one (which has been deleted).

[yohanboniface]

How the backup did not restore also the ids in the umap_map table ?

[gislars]

I should have provided a more detailed explanation of the issue. Of course, the restore was complete. But if data loss occurs between two backup points, all data since the last backup is lost.
That's exactly what happened. The data of users who created new maps or changed existing ones after the backup was lost.
In the case of anonymous maps, I had a case where a user with a previously created link now had access to someone else's map (and the map they had created was lost). With the number of users on a server, the probability of such a case occurring also increases.

I think this issue is only about anonymous maps, maps from accounts don't have an edit link.

Increasing the backup frequency would, of course, work against this.

[yohanboniface]

I think this will be fixed when we fix #905