TERM unconditionally set to "xterm", regardless of config

[Micah Cowan]

Binary package hint: xfce4-terminal

Xubuntu 11.04 Natty Narwhal

xfce4-terminal 0.4.7-0ubuntu1
libvte9 0.27.90

I wish to enable 256-color support in apps running under xfce4-terminal; but even though I've set TERM to this value in the config (and verified it in .config/Terminal/terminalrc), the TERM variable winds up having the value "xterm".

Upon digging a little further, xfce4-terminal correctly sets the TERM variable in the environment vector that it then passes through to vte via vte_terminal_command_full (this takes place within the terminal_screen_launch_child function found in terminal/terminal-screen.c). However, vte_terminal_fork_command_full copies everything from that vector _except_ the TERM variable, unconditionally replacing that with a value that should be set by calling vte_pty_set_term (this happens in src/pty.c:__vte_pty_merge_environ(), which is called by (and gets the TERM value from) src/pty.c:__vte_pty_spawn, which in turn is called by src/vte.c:vte_terminal_fork_command_full() ). xfce4-terminal doesn't appear to ever call that function anywhere, and thus vte defaults to "xterm". So the appropriate fix would seem to be to make xfce4-terminal call that function to register the correct TERM value.

[Micah Cowan (micahcowan)]

Er, vte_pty_set_term isn't callable, since the pty object doesn't exist before __vte_pty_spawn. The user-callable fn is vte_terminal_set_emulation.

[Micah Cowan (micahcowan)]

According to the discussion on the Gnome VTE bug linked, calling vte_terminal_set_emulation won't work either, unless it happens to be recognized as a supported emulation mode. "xterm-256color" isn't, so this solution wouldn't work.

There doesn't seem to be an obvious, clean way to fix the problem within xfce4-terminal; vte is the one holding all the cards AFAICT. According to discussion on the Gnome VTE bug, vte_terminal_fork_command_full is "just a wrapper" around some other functions, but one of those functions (__vte_pty_spawn) probably isn't safe to call by users.

Perhaps the correct solution should be for vte to revert to its previous behavior, whereby it didn't brutally murder pre-existing TERM settings when the terminal app sets them. If the upstream vte folks don't want to consider this, Ubuntu probably should.

[Micah Cowan (micahcowan)]

Added vte, until it's clearer which of xfce4-terminal and vte should fix this (as I said, though, it looks to me like only vte _can_ fix it, though upstream seems unwilling).

[Micah Cowan (micahcowan)]

Note that gnome-terminal isn't effected, since gnome-terminal doesn't give the user the option to specify the TERM value to begin with. This is generally a desirable feature to have, though.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Henning Hoefer (hoeferh)]

This bug seems to be still present in Xubuntu 11.10

[Gytis Žilinskas (gytis-zilinskas)]

still present and very very annoying

[Ivan Frederiks (idfred)]

Still present in Precise.

[Ryan Kinderman (wizderman)]

Still present in Quantal.

[TK (tkrishan)]

Still present in Raring

[Micah Cowan (micahcowan)]

FWIW, the workaround I've been using for some time now is:

if [ \( "x$COLORTERM" = "xgnome-terminal" -o "x$COLORTERM" = "xTerminal" -o "x$COLORTERM" = "xxfce4-terminal" \) -a "x$TERM" = "xxterm" ] &&
        infocmp xterm-256color >/dev/null 2>&1; then
    TERM=xterm-256color
fi

in my .bashrc or what have you. The "Terminal" was what worked in Precise and prior; "xfce4-terminal" is what COLORTERM is now set to.

(The infocmp command verifies that there is a terminfo database entry for "xterm-256color", so it doesn't get set and then terminal apps haven't a clue how to talk to the terminal.)

[Micah Cowan (micahcowan)]

(the line wrapped for the first "if" line; that needs to be a single line to work)

[Ash (flubba86)]

Is there any chance of this being looked at? I use XFCE4 and this bug affects me.

[Egmont Koblinger (egmont-gmail)]

FYI: Newer versions of vte/gnome-terminal set TERM=xterm-256color (hardcoded; no config option available).

[Theo Linkspfeifer (lastonestanding)]

https://git.xfce.org/apps/xfce4-terminal/commit/?id=fa9d95c99d3c73c80fc42fbc23b73a5a8d5bae79

The config option was removed in xfce4-terminal also. Like mentioned in the previous comment, it is TERM=xterm-256color by default now.