1865778 - [TSF] Make `TSFTextStore` notify TSF/TIP of text changes after CRLFs are inserted

Status: ASSIGNED

(Core :: DOM: UI Events & Focus Handling, task, P2)

Description

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

TIP may have a feature which inserts CRLFs within long text, like a template text feature. However, after fixing bug 1853986, we will reply text and offset data as they are replaced with LFs when TSF/TIP queries the content. Therefore, in the following case, TSF/TIP will get odd result.

1. Inserts "abc\r\ndef"
2. Query selection offset

Then, selection offset becomes "abc\ndef".length instead of "abc\r\ndef".length. I.e., from the TIP point of view, selection is oddly collapsed between e and f rather than after f.

For solving this issue in TSF-aware app side, we need to notify TSF/TIP of a text change and a selection change that all CRLFs of the inserted text range is replaced with LFs. However, we've not done it yet.

In the worst case, the text containing CRLFs may come during a composition. In that case, notifying the composing string change may cause committing the string in better case. Instead, it might cause the TSF/TIP stop working until Firefox process is restarted or just a crash.

On the other hand, we're not sure whether there is such TIP. E.g., ATOK (Japanese 3rd party's IME) has a template text insertion feature, however, linebreaks cause synthesizing Enter key events instead of inserting CRLFs directly. This must be better for rich text editor apps like Word, etc because rich text editor may have two line breaks, one is a paragraph separator and the other is a line breaker like Enter key and Shift + Enter key on browsers.

Therefore, in this bug, we should just put the change notification into the queue. Once we'll get IMEs (which can insert CRLFs) from the telemetry added in bug 1865256, let's check whether the simple fix here is enough or not.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Provided the telemetry is working, there currently seem to be no IMEs that insert CRLFs being used on Nightly: https://sql.telemetry.mozilla.org/queries/96469

Comment 2

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

(In reply to Jeff Muizelaar [:jrmuizel] from comment #1)

Provided the telemetry is working, there currently seem to be no IMEs that insert CRLFs being used on Nightly: https://sql.telemetry.mozilla.org/queries/96469

Yeah, if we don't get any IME names in early beta builds, I think that it's okay to ship bug 1853986 without fixing this.
(Although I'll try to fix this in this month.)

Comment 3

[Jeff Muizelaar [:jrmuizel]]

I updated the query to include beta and there are still no IME names.