Unexpected user ID shown instead of name

[fetimo]

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Hi, apologies if this is a duplicate issue, I have looked but couldn't see anything that looked similar.

Steps to reproduce

1. Create a SAML user
2. Write a message to them

Expected behaviour

The message preview for a user what is sent should be consistent. E.g. when I @[person] I expect the message to show the same, rather than be replaced by their user ID.

Preview

Sent

Actual behaviour

The message is not consistent with the preview.

Talk app

Talk app version: 15.0.6

Custom Signaling server configured: yes

Custom TURN server configured: yes

Custom STUN server configured: yes

Browser

Microphone available: yes

Camera available: yes

Operating system: macOS

Browser name: Chrome

Browser version: 114

Nextcloud Version: 25.0.7 Enterprise

[nickvergessen]

I'm not aware that | is a valid character for user ids:

server/lib/private/User/Manager.php

Lines 710 to 715 in 346344c

	// Check the name for bad characters
	// Allowed are: "a-z", "A-Z", "0-9", spaces and "_.@-'"
	if (preg_match('/[^a-zA-Z0-9 _.@\-\']/', $uid)) {
	throw new \InvalidArgumentException($l->t('Only the following characters are allowed in a username:'
	. ' "a-z", "A-Z", "0-9", spaces and "_.@-\'"'));
	}

So it also is not matched by the regular expression later on that tries to match mentions:

• server/lib/private/Comments/Comment.php

  Line 222 in 7aa97dc

  $ok = preg_match_all("/\B(?<![^a-z0-9_\-@\.\'\s])@(\"guest\/[a-f0-9]+\"|\"group\/[a-z0-9_\-@\.\' ]+\"|\"[a-z0-9_\-@\.\' ]+\"|[a-z0-9_\-@\.\']+)/i", $this->getMessage(), $mentions);

[fetimo]

Interesting, thanks for the quick reply Nick! I'm not familiar with this code but I guess that SAML users don't have the same restrictions? What do you suggest in this scenario?

[nickvergessen]

The auth0/saml user backend could change them before creating the users in Nextcloud. Or someone sends a PR to all place

[nickvergessen]

Moving to server therefore

[szaimen]

Which NC version?

[nickvergessen]

Also happens on master. The problem is the auth0 user backend contains | which is not matched by the regex when finding mentions in comments and anything else because the user default user backends don't support the character and it's not listed as supported in the manager.

The question is whether we want to extend the character list and allow it, or not, in which vase the auth0 backend should try to change it's account pattern and migrate existing users over