[Bug]: Federated Share gets deleted on acceptance by the receiving user

[MahdiBaghbani]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Clicking “Add remote share” on the receiver triggers
DELETE /apps/files_sharing/api/externalShares/<id>
instead of the expected POST, so the incoming share is removed and never appears.

This is true for both the:
sharing via typing in the share to external user
sharing via link and opening the link, then triggering the add to your own Nextcloud host

I've discovered this by trying to integrate Nextcloud version 31 into OCM Test Suite.

Steps to reproduce

Important

We use a custom docker image that only has the base Nextcloud installed, the notifications app IS NOT installed.

See the docker file at dev-stock

Steps

1. On nc1.docker log in as bob, share test.txt with alice@nc2.docker via federated share
2. On nc2.docker log in as alice; a Remote share dialog pops up
3. Press Add remote share

See the videos (from Cypress automating the process, that's why it's a bit fast)

share-with-nc-to-nc.mp4

share-link-nc-to-nc.mp4

This might be interesting to @ArtificialOwl

Expected behavior

Expected behaviour

POST /apps/files_sharing/api/externalShares is issued, the share is mounted, file visible after reload.

Actual behaviour

Network console records:

Method: DELETE
URL: https://nc2.docker/apps/files_sharing/api/externalShares/1
Status: 200

Nextcloud Server version

31

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Apache (supported)

Database engine version

MariaDB

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

[MahdiBaghbani]

Versions 30 and prior are not affected, 31 and master (v32.0.0) are however currently suffer from this bug.

[michielbdejong]

It seems the 'Cancel' button is selected by default. Maybe in previous versions of Nextcloud the default action was to accept an incoming share?

[michielbdejong]

Your PR looks correct to me though, so there probably is a bug as you say. Did you also see the DELETE happening when manually clicking the 'Add remote share' button? And what happens when you click the 'Cancel' button?

[MahdiBaghbani]

@michielbdejong Yes, I did test manually both v31 and v32 with the embedded Firefox, same behaviour, also Cancel works as expected and would trigger DELETE

It seems the 'Cancel' button is selected by default. Maybe in previous versions of Nextcloud the default action was to accept an incoming share?

Cypress code is set to select the button with the Add remote share text inside of it, it would not click on Cancel by accident

[provokateurin]

Fix is at #53840