Files
buzz/desktop/src
Taylor Ho 074561233e fix(composer): preserve caret when inserting mentions mid-message (#6531)
**Category:** fix
**User Impact:** Users can insert mentions earlier in a draft and
continue typing without the caret corrupting the rest of the message.

**Problem:** Caret correction ran after every document change, so typing
a mention before existing text repeatedly advanced across the mention
separator and interleaved spaces into the draft. **Solution:** Limit
correction to the autocomplete settlement it was designed for, with
transaction-level and browser-level regression coverage for known and
unregistered mentions.

<details>
<summary>File changes</summary>

**desktop/src/features/messages/lib/mentionHighlightExtension.ts**
Restricts trailing-space caret advancement to an armed autocomplete
settlement instead of every document change.

**desktop/src/features/messages/lib/mentionHighlightExtension.test.mjs**
Exercises the real ProseMirror plugin state and verifies mid-draft
mention typing, unknown tokens, end-of-message typing, and
completed-mention separators.

**desktop/tests/e2e/mentions.spec.ts**
Reproduces the reported composer workflow in Chromium and covers the
same corruption path for an unregistered `@token`.

</details>

## Reproduction steps

1. Open a channel and enter `hello world` in the composer.
2. Move the caret between `hello` and ` world`.
3. Type ` @bo`, select `bob` from autocomplete, and continue typing
`abc`.
4. Confirm the composer reads `hello @bob abc world` with the caret
after `abc`.
5. Repeat with an unregistered token such as ` @zzq` and confirm the
existing text remains intact.

## Before / After

| Before | After |
| --- | --- |
| Typing after a mid-draft mention walks the caret through the existing
message. | Continued typing stays after the inserted mention. |
| ![Before: mention caret corrupts existing draft
text](https://d24qwcpro867f5.cloudfront.net/repos/buzz/prs/6531/mention-caret-before.gif)
| ![After: caret remains after the inserted
mention](https://d24qwcpro867f5.cloudfront.net/repos/buzz/prs/6531/mention-caret-after.gif)
|

---------

Signed-off-by: Taylor Ho <taylorkmho@gmail.com>
Co-authored-by: Mongo <5398c5fd039b963ce132b3e078e7c4af097dd997517bb5e14c2682fe68c25197@buzz.block.builderlab.xyz>
2026-08-21 18:48:21 -06:00
..
2026-03-09 13:02:11 -07:00