Re: Problems with unicode characters under emacs and Xorg

[David Edmondson <dme@dme.org>]

On Monday, 2020-11-02 at 01:21:00 -08, dm-list-email-notmuch@scs.stanford.edu wrote:

> David Edmondson <dme@dme.org> writes:
>
>> I haven't seen this. Threads with a lot of complex HTML content (lots of
>> nested tables, for example) can take a long time to render for me, but
>> that is generally interruptable.
>>
>> Could you share one of these messages, or a sufficiently similar test
>> case?
>
> Thanks for the reply.  I can send one of these emails to you privately
> if necessary, as it might contain semi-sensitive information.  However,
> I think all you need is the subject line.  For example:
>
> Subject: =?UTF-8?B?RGF2aWQ6IEhvdy1UbyBIaXJlIHRoZSBCZXN0IFJlbW9kZWxpbmcgQ29udHJhY3RvciDwn5Od?=
>
> That subject line alone triggers the problem, because any search
> returning that thread triggers the problem.  When decoded, the subject
> line ends with unicode code point 0x1F4DD (MEMO).  Indeed, if I open up
> a fresh emacs, and, independent of notmuch, type "C-x 8 RET memo RET",
> it causes the emacs to hang for a minute or so.

This works fine for me, and I get an appropriate character (not just the
hex box).

According to `describe-char' it's rendered using the Symbola font. Do
you have that installed? (It's the "font-symbola" package on Debian I
believe.)

For some time I've had:

  (set-fontset-font t 'symbol "Symbola" nil 'prepend)

in ~/.emacs.el, but I just tested without and it doesn't seem to be
required.

> Arguably this is a limitation of emacs or fontconfig, or I've installed
> too many fonts on my system, or I've installed too few fonts (because
> after all that computation it just renders a box with hext digits 01F4DD
> in it instead of showing the MEMO icon).  However, the problem only
> happens with notmuch, because notmuch is the only emacs functionality I
> need that renders anything other than a very limited set of unicode
> characters.  So if there's any way either to workaround the problem, or
> to copy whatever other notmuch users are doing (is there some particular
> unicode font I should just install on my system?), I would be very
> happy.
>
> Thanks,
> David

dme.
-- 
I walk like a building, I never get wet.