1341977 - Cannot move caret after trying to do "Kakutei-Undo" of Apple Japanese Input in twitter.com

Status: NEW

(Core :: DOM: UI Events & Focus Handling, defect, P3)

Description

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

STR:
1. Open https://twitter.com/ and log into it.
2. Set focus to the editor to tweet.
3. Input "テスト" and commit it.
4. Input "テスト" again and commit it.
5. Press Ctrl+Backspace

Expected result:
2nd "テスト" becomes marked text and it's impossible to convert it to other string.

Actual result:
Nothing happened and cannot move focus with arrow keys anymore.


I think that the editor to tweet hacks something. Therefore, it may be okay not to be able to do "Kakutei-Undo" but we should avoid the latter issue.

I reproduce this bug either in e10s mode nor non-e10s mode.

Comment 1

[Sylvestre Ledru [:Sylvestre]]

Moving to p3 because no activity for at least 1 year(s).
See https://github.com/mozilla/bug-handling/blob/master/policy/triage-bugzilla.md#how-do-you-triage for more information

Comment 2

[Makoto Kato [:m_kato]]

Since this is interesting, so I investigate this today.

Twitter's UI removes all text by [ctrl] + [delete] on macOS. Since if their contents/scripts handle "Backspace" key to remove all content, their scripts remove all by it.

When using Apple Japanese IME with [ctrl] + [delete], before Firefox sets composition (it means to fire compositionstart and compositionupdate) for reconverting composition, twitter removes all text unfortunately. So this issue will occur. (also, Chrome is same)

But Safari's behavior is different. When using [ctrl] + [delete], they set IME Process key to keyCode instead of backspace key. So this issue doesn't occur on Safari.

This process key is correct when IME is handled. But I guess that Firefox and Chrome are also correct since both doesn't handle IME yet... Hmm....

Comment 3

[Makoto Kato [:m_kato]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=1b348223d8e215e3d4dbecbc1ad59ae1d7ce0177

Comment 4

[Makoto Kato [:m_kato]]

Attachment: Bug 1341977 - Use async API of NSTextInputClient to handle key event.

[Ctrl] + [Backspace] is assigned as deleting all tweet in Twitter. [Ctrl] + [Backspace] is assigned as commit-undo in Apple Japanese input method. When using it, Gecko fires key down event of [Ctrl] + [Backspace], not process key, commit-undo in Apple IM doesn't work well. In this situation, WebKit fires process key correctly, so it works expectedly.

Actually, since WebKit uses undocumented API (async version of NSTextInputClient, supported from 10.10) for key event by https://webkit.org/b/130479, this doesn't occur.

Since this change might be risky, I would like to turn on this for Nightly and early beta only. If no problem, I will turn on this for 71 release.

Comment 5

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Moving all open keyboard/IME handling bugs to DOM: UI Events & Focus Handling component.