Mention autocomplete triggers on email addresses

[deepak0x]

The mention popup in ChatInput fires whenever you type @ after a space. Problem is, that also matches email addresses — typing something like contact admin @example.com pops up the member list and starts filtering against "example.com".

The trigger logic in useSearchMentionUser.js:23-26:

if (
  lastChar === '@' &&
  (message.length === 1 || message[message.length - 2] === ' ')
)

It checks "is this an @ after a space?" but doesn't try to figure out whether the user is mentioning someone or just typing an email.

Steps to reproduce:

1. Open EmbeddedChat in any room
2. In the message input, type contact admin @example.com
3. The mention popup appears as soon as you hit @
4. It filters members against "example.com"

Expected behavior:

Mention popup shouldn't fire when the user is typing an email address.

Actual behavior:

Popup fires on any @ preceded by a space. You have to dismiss it or ignore it while finishing the email.

Code reference:

packages/react/src/hooks/useSearchMentionUser.js:23-26

[deepak0x]

@Spiral-Memory found this while looking at mention-related code paths. The fix would be to add a lookahead check after the @ trigger — if the characters following @ contain a dot before any space (like example.com), skip triggering the popup. This keeps the existing trigger simple while filtering out email-like patterns. Happy to pick this up.

[yash113gadia]

I'd like to work on this!

Looking at useSearchMentionUser.js:23-26, a couple of observations on the current behavior:

• A normal inline email like john@example.com actually doesn't trigger the popup, since the @ is preceded by a word character rather than a space.
• The popup also already auto-hides when the query matches no members (setShowMembersList(filteredMentionMembers.length > 0)).

So the remaining issue is the case in the report: typing @ after a space followed by a domain (e.g. @example.com), where the popup flickers and filters against partial matches while you finish typing.

My proposed approach: once in mention-reading mode, suppress the popup when the text after @ looks like a domain (a . followed by TLD-like characters). That covers the email/domain case without affecting normal @username mentions.

One edge case I want to confirm before coding: Rocket.Chat usernames can contain dots — do you have a preferred heuristic so we don't accidentally suppress a legitimate mention like @john.doe? Happy to go with whatever direction you'd prefer.