Bug#1001322: gdb: Can't seem to turn colour off

[Mouse]

Package: gdb
Version: 10.1-1.7
Severity: important

Dear Maintainer,

I'm not sure I've marked this bug report correctly; it was not clear
what values I should pick for "borderline unusable, but for only a
small fraction of all users". Please reclassify as appropriate.

gdb borders on unusable when using a terminal type that does not
support X3.64 escape/control sequences, even though $TERM is set
correctly and gdb thus should know this is the case. For example,
here's what I see, cut-and-pasted directly from the terminal window I
ran gdb in:

[?2004h(gdb) finish
Run till exit from #0 [34m0xb770acf9[m in [33m__kernel_vsyscall[m ()
[34m0xb74b82f7[m in [33m__GI___poll[m ([36mfds[m=0xbffcce50, [36mnfds[m=2, [36mtimeout[m=-1)[m
[m at [32m../sysdeps/unix/sysv/linux/poll.c[m:29
29 in [32m../sysdeps/unix/sysv/linux/poll.c[m
[?2004h(gdb) finish
Run till exit from #0 [34m0xb74b82f7[m in [33m__GI___poll[m ([36mfds[m=0xbffcce50, [36mnfds[m=2, [36mtimeout[m=-1)[m
[m at [32m../sysdeps/unix/sysv/linux/poll.c[m:29
[34m0x004b48cb[m in [33msubproc_finish[m ([36msp[m=0x1b04250, [36moutstr[m=0xbffcced8, [36merrstr[m=0xbffcced0)[m
[m at [32mfind-invite.c[m:1261
1261 np [31m=[m [01mpoll[m[31m(&[mpfds[31m[[m[35m0[m[31m],[mnpfd[31m,[mINFTIM[31m);[m
Value returned is $1 = 2
[?2004h(gdb) n
126204l [01;34mif[m [31m([mnp [31m<[m [35m0[m[31m)[m
[?2004h(gdb) p np
$2 = 2l
[?2004h(gdb)

Telling gdb "!printenv TERM" prints "mterm4l"; the actual $TERM setting
is "mterm" - I conjecture that gdb is postprocessing the output of the
command, adding yet more inappropriate X3.64 sequences.

If there is a way to turn this off, it is far too well hidden; I have
found commands for changing the colours (er, sorry, "colors") used to
decorate various pieces of the UI, but nothing at all for completely
turning it all off. Nor should I need to, when I've already told gdb,
via $TERM, that X3.64 sequences will not work.

Mouse

-- System Information:
Debian Release: 11.1
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 4.9.0-9-686-pae (SMP w/2 CPU threads)
Locale: LANG=en_CA.ISO-8859-1, LC_CTYPE=en_CA.ISO-8859-1 (charmap=ANSI_X3.4-1968) (ignored: LC_ALL set to C), LANGUAGE=en_CA.ISO-8859-1
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gdb depends on:
ii libbabeltrace1 1.5.8-1+b3
ii libc6 2.31-13+deb11u2
ii libdebuginfod1 0.183-1
ii libexpat1 2.2.10-2
ii libgcc-s1 10.2.1-6
ii libipt2 2.0.3-1
ii liblzma5 5.2.5-2
ii libmpfr6 4.1.0-3
ii libncursesw6 6.2+20201114-2
ii libpython3.9 3.9.2-1
ii libreadline8 8.1-1
ii libsource-highlight4v5 3.1.9-3+b1
ii libstdc++6 10.2.1-6
ii libtinfo6 6.2+20201114-2
ii libxxhash0 0.8.0-2
ii zlib1g 1:1.2.11.dfsg-2

Versions of packages gdb recommends:
ii libc6-dbg [libc-dbg] 2.31-13+deb11u2

Versions of packages gdb suggests:
pn gdb-doc <none>
pn gdbserver <none>

-- no debconf information