1237216 - [TSF] Unnecessary composition events are raised when typing Korean characters

Status: RESOLVED FIXED

(Core :: Widget: Win32, defect)

Description

[Park, Chulmin]

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.106 Safari/537.36

Steps to reproduce:

1. Typing Korean characters inside a div tag with content-editabled like below.
    <div>간</div>
2. Type a Korean character ('ㅏ' in this example) which can occur "compositionend" event.
    <div>가나</div>


Actual results:

When you type 'ㅏ', events will be raised like below.
  - compositionupdate ('가') -> compositionend ('가') -> compositionstart -> compositionend ('') -> compositionstart -> compositionupdate ('나')

  Unnecessary composition events are following after "compositionend" event for '가'.



Expected results:

Events might be raised like below.
  - compositionupdate ('가') -> compositionend ('가') -> compositionstart -> compositionupdate ('나')

Comment 1

[Park, Chulmin]

It only happens when TFS is enabled.

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(away 4/27 - 5/6)]

Attachment: TSFTextStore should forget redundant pending composition events for Korean TIPs

MS-IME for Korean behaves odd.

At typing a Hangul character which causes committing current composition and appending new Hangul character after that, it modifies composition range *before* notifying us of composition end. Therefore, before handling composition end, we record a restart composition with new range. However, this is ended by following end composition notification. This is the redundant compositionstart and compositionend events.

When we record a pending action for composition end, we should check if it's actually changes composition string. If it's not changed, we should remove the pending action from preceding composition start to current (composition end).

Comment 3

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(away 4/27 - 5/6)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/73c6bdc7aa58f9139eb2d72377cffb56ad461f83
Bug 1237216 TSFTextStore should forget redundant pending composition events for Korean TIPs r=emk

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/73c6bdc7aa58