[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [BUG] italics run past where they should

From: G. Branden Robinson
Subject: Re: [BUG] italics run past where they should
Date: Wed, 17 Aug 2022 07:12:37 -0500

Hi Alex,

Good news--I finally see a problem.

At 2022-08-17T13:49:35+0200, Alejandro Colomar wrote:
> I made the reproducer smaller, so that it's reasier to investigate.  I
> produced a one-liner file, and then script(1)ed the reproduction of
> the bug (I made the terminal shorter, 80x3, to get less blank lines
> from less(1)):

In the future, when sending around a typescript that includes
screen-clearing escape sequences, it might be a good idea to capture
timing information.  Modern script(1) supports this, or you can use the
classic tool beloved of NetHack players, ttyrec(1).

> Attached you'll find the offense line, and the typescript log.

Yes, I see trouble.

Script started on 2022-08-17 13:47:53+02:00 [TERM="xterm-256color" 
TTY="/dev/pts/4" COLUMNS="80" LINES="3"]
~/tmp^GESC[01;32malx@asus5775ESC[00m:ESC[01;34m~/tmpESC[00m$ less -R 
ESC[?2004l^MESC[?1049hESC[22;0;0tESC[?1hESC=^M       ESC[1mint 
syscall(SYS_membarrier, int ESC[4mESC[22mcmdESC[24mESC[1m, unsigned int 
ESC[4mESC[22mflagsESC[24mESC[1m, int 

Okay, that looks like a riot of noise, but the important thing is that
we can see around "cmd" pair of CSI escape sequences, 22 m and 24 m.

As discussed earlier in the thread, "22" restores the "intensity" to
"normal" (i.e., in this case, turns bold off) and "24" turns off
underlining.  A CSI 1 m sequence, which turns bold back on, follows.


This is you doing your search.

       ESC[1mint syscall(SYS_membarrier, int 
ESC[4mESC[22mESC[7mcmdESC[27mESC[1m, unsigned int 
ESC[4mESC[22mflagsESC[24mESC[1m, int 

This is the same line from the document, with the match now highlighted.

We see that after CSI 22 m, the pager has interpolated a CSI 7 m
sequence before the match and a CSI 27 m afterward.  This makes sense;
again as discussed before, these are "inverse" and "positive"

But where's the CSI 24 m sequence we originally had?

This is the bug.


Attachment: signature.asc
Description: PGP signature

reply via email to

[Prev in Thread] Current Thread [Next in Thread]