[Due for payment 2025-10-07] At-mentions do not work when user's handle starts with a single character then a dot

[chuckdries]

Version Number: v9.2.0-4
Reproducible in staging?: yes
Reproducible in production?: yes
If this was caught during regression testing, add the test name, ID and link from TestRail:
Email or phone of affected tester (no customers):
Logs: https://stackoverflow.com/c/expensify/questions/4856
Expensify/Expensify Issue URL:
Issue reported by: @chuckdries
Slack conversation #engineering-chat

Action Performed:

1. Invite a user to your workspace whose email starts with a single character followed by a dot, followed by some more characters
2. begin typing @ and their handle to @mention that user in the workspace chat
3. use arrow keys to select that user in the autocomplete and press enter

Expected Result:

• Autocomplete inserts the user's handle, which turns blue to indicate it is a Mention

Actual Result:

• Autocomplete inserts the user's handle, but it does not turn blue. See video

Workaround:

The user can manually type the full email then press space (specifically not accepting the autocomplete)

Platforms:

Select the officially supported platforms where the issue was reproduced:

• Android: App
• Android: mWeb Chrome
• iOS: App
• iOS: mWeb Safari
• iOS: mWeb Chrome
• Windows: Chrome
• MacOS: Chrome / Safari
• MacOS: Desktop

Platforms Tested:

On which of our officially supported platforms was this issue tested:

• Android: App
• Android: mWeb Chrome
• iOS: App
• iOS: mWeb Safari
• iOS: mWeb Chrome
• Windows: Chrome
• MacOS: Chrome / Safari
• MacOS: Desktop

Screenshots/Videos

Add any screenshot/video evidence

c.dot.chuckles.not.working.mp4

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Issue Owner

Current Issue Owner: @

Issue Owner

Current Issue Owner: @trjExpensify

Issue Owner

Current Issue Owner: @trjExpensify

[melvin-bot]

@chuckdries the AutoAssignerTriage label has been deprecated. Please use Bug for issue triage. See https://stackoverflowteams.com/c/expensify/questions/14418 for more details.

[melvin-bot]

Triggered auto assignment to @trjExpensify (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details. Please add this bug to a GH project, as outlined in the SO.

[melvin-bot]

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[mukhrr]

Proposal

Please re-state the problem that we are trying to solve in this issue.

Users with usernames containing dots (like @k.raim or @f.fepov) cannot be properly mentioned in workspace chat. When typing @ and selecting these users from the autocomplete, the mention doesn't turn blue and doesn't function as a clickable mention in posted messages.

1. Register with corporate email (for ex. kamil23@trest.com)
2. Create a workspace
3. Invite a member with the SAME company name after @ as yours in 1st step and with . (for ex. k.kamil45@trest.com) See trest is the same with your email and invited member's email
4. Try to mention @k.kamil45 in WS chat

What is the root cause of that problem?

The root cause is that ExpensiMark (from the expensify-common library) doesn't recognize usernames with dots as valid mention patterns. When ExpensiMark parses text:
@fepovi8714 → <mention-short>@fepovi8714</mention-short>
@f.fepov → @f.fepov (remains as plain text)

This affects both the live markdown parsing (composer input) and HTML parsing (posted messages), preventing proper mention highlighting and functionality.

What changes do you think we should make in order to solve the problem?

We can modify the parseExpensiMarkWithShortMentions function in src/libs/ParsingUtils.ts to add custom logic that:

• For live markdown parsing: Detect mentions with dots that ExpensiMark missed and manually create mention-short ranges for them.
  

  App/src/libs/ParsingUtils.ts

  Lines 57 to 62 in 6517be6

  	function parseExpensiMarkWithShortMentions(text: string, availableMentions: string[], currentUserMentions?: string[]) {
  	'worklet';
  	const parsedRanges = parseExpensiMark(text);
  	return decorateRangesWithShortMentions(parsedRanges, text, availableMentions, currentUserMentions);
  	}

• For HTML parsing: Detect plain text mentions with dots and convert them to HTML tags

What specific scenarios should we cover in automated tests to prevent reintroducing this issue in the future?

We should add tests to tests/unit/libs/ParsingUtilsTest.ts covering:

What alternative solutions did you explore? (Optional)

Result:

Screen.Recording.2025-09-03.at.03.33.39.mov

[trjExpensify]

@puneetlath can you take a look at this, as I suspect it was known when implementing mentions? Thanks!

[puneetlath]

I don't think it was known. So let's go ahead and make this external to fix.

[melvin-bot]

Unable to auto-create job on Upwork. The BZ team member should create it manually for this issue.