Re: [BUG] italics run past where they should

[G. Branden Robinson]

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"]
ESC[?2004hESC]0;alx@asus5775: 
~/tmp^GESC[01;32malx@asus5775ESC[00m:ESC[01;34m~/tmpESC[00m$ less -R 
offense_line.out
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 
ESESC[4mESC[22mcpu_idESC[24mESC[1m);ESC[0mESC[m

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.

ESC[7moffense_line.out 
(END)ESC[27mESC[K^MESC[K/ESC[KcESC[KmESC[Kd^MESC[K...skipping...

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 
ESC[4mESC[22mcpu_idESC[24mESC[1m);ESC[0mESESC[m

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"
respectively.

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

This is the bug.

Regards,
Branden

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