Add delete confirmation dialogs

[jplouvel]

Problem

When users delete files in a synced folder, there's no warning. This causes accidental data loss, especially for users unfamiliar with sync behavior.

OneDrive and Dropbox both have safety dialogs that Nextcloud lacks:

• "First delete" educational popup explaining files will be deleted everywhere
• Confirmation when deleting shared files or moving files out of sync folder

Proposed Solution

• First-time delete dialog: Explain that deletion syncs everywhere + mention trash recovery (with "Don't show again" checkbox)
• Shared files confirmation: "This file is shared with X people. Delete anyway?"
• Mass deletion warning: "You're about to delete X files. Continue?" (configurable threshold)

[Rello]

Hello,

which OS are you talking about?
when using the Nextcloud Desktop Client, it only "subscribes" to your explorer/finder. the client is not able to trigger any deletion confirmations.

technically you are working on your explorer/finder and deleting files there. the OS might ask you for confirmation/trash or whatever is configured. once you performed an action, the Desktop Client gets notified by the OS and then syncs whatever action was performed to the Nextcloud Server.
There is no point where we can interrupt any deletion.

I just tried OneDrive. this is no confirmation. you cannot abort the deletion. the file is already deleted locally. this is just a hint that the file is still in the server trash. This is the same as Nextcloud behaves out of the box. Any deletion will be in the server trash.

[jplouvel]

Thanks for the clarification on how the sync client works!

However, I can confirm these dialogs do exist. I tested Dropbox on Windows 11 yesterday and got a warning message when deleting a file.

Here are also two screenshots found online showing these dialogs:

I'm not asking to block deletions, just an informational dialog like these, with an easy way to undo (Cancel button or direct link to trash).

This kind of educational UX really helps new users understand how sync works and reduces panic when they realize files are gone from all devices. Experienced users can simply check "Don't show again" and never see it.