995922 - Remove JOHAB support

Status: RESOLVED FIXED

(Core :: Internationalization, enhancement)

Description

[Henri Sivonen (:hsivonen) (not reading bugmail until 2026-07-27)]

As far as I can tell, the only place where we use our JOHAB code in Firefox these days is at
http://mxr.mozilla.org/mozilla-central/source/gfx/thebes/gfxFontUtils.cpp#1225
for decoding legacy font names.

Telemetry suggests that no one actually uses fonts like that:
http://telemetry.mozilla.org/#release/28/DECODER_INSTANTIATED_JOHAB/saved_session/Firefox

Since we already don't support the full set of legacy encodings for font names, I suggest we remove JOHAB support from the tree.

jfkthame, are you OK with this?

Comment 1

[Jonathan Kew [:jfkthame]]

I'm OK with this from the font-name-encoding point of view; cc'ing jdaggett to make sure he's also aware of it and can speak up in case of any concerns.

What encoding gets used for web content that is tagged as charset=x-johab? What is used by the View / Character Encoding / Korean option?

In any case, given the current discussion about the position of c-c in relation to m-c, perhaps it'd be better not to rush the actual removal of support if there's a possibility that email-related code is using it.

Comment 2

[Henri Sivonen (:hsivonen) (not reading bugmail until 2026-07-27)]

(In reply to Jonathan Kew (:jfkthame) from comment #1)
> What encoding gets used for web content that is tagged as charset=x-johab?

Already the same encoding as for content tagged charset=foobar-invalid. I.e. depends on the TLD of the site or on the browser configuration with localization-dependent defaults.

> What is used by the View / Character Encoding / Korean option?

EUC-KR.

> In any case, given the current discussion about the position of c-c in
> relation to m-c, perhaps it'd be better not to rush the actual removal of
> support if there's a possibility that email-related code is using it.

I'm thinking of fixing bug 937056 first to give c-c some infrastructure for moving stuff over. Once the infrastructure for c-c to receive converters exists, I think it's up to Thunderbird devs to pick up the removed encodings, though.

Comment 3

[Henri Sivonen (:hsivonen) (not reading bugmail until 2026-07-27)]

Attachment: WIP

Comment 4

[Henri Sivonen (:hsivonen) (not reading bugmail until 2026-07-27)]

Attachment: Remove JOHAB

https://tbpl.mozilla.org/?tree=Try&rev=d111cc1f0865

Comment 5

[Masatoshi Kimura [:emk]]

Comment on attachment 8419996 [details] [diff] [review]
Remove JOHAB

Yay!

Comment 6

[Henri Sivonen (:hsivonen) (not reading bugmail until 2026-07-27)]

Thanks.
https://hg.mozilla.org/integration/mozilla-inbound/rev/b5eef7023c52

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/b5eef7023c52