misc/47674: vt220 terminfo description seems incorrect

[uwe%NetBSD.org@localhost]

>Number:         47674
>Category:       misc
>Synopsis:       vt220 terminfo description seems incorrect
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 20 23:05:00 +0000 2013
>Originator:     Valery Ushakov
>Release:        NetBSD 6.1
>Organization:
>Environment:
>Description:
I use putty with TERM=vt220.  I've upgraded one of my machines to
netbsd6 recently and noticed that cursor keys started to misbehave in
some apps, e.g. in GNU screen copy mode.

After a bit of poking around I found that the terminfo description of
vt220 seems incorrect.  I assume we get it from ncurses as upstream
and the problem is present there too.

* It declares cursor keys to transmit normal \E[ aka CSI sequences:

    kcuu1=\E[A,
    kcud1=\E[B,
    kcuf1=\E[C,
    kcub1=\E[D,

* But it declares init string that switches them to applicaction mode
  that uses \EO aka SS3 sequences:

    is2=...\E[?1h...,

http://vt100.net/docs/vt220-rm/chapter2.html#S2.5.1
http://vt100.net/docs/vt220-rm/chapter4.html#S4.6.8
http://vt100.net/docs/vt220-rm/table3-2.html

>How-To-Repeat:
Use misc/screen package.
Run it with TERM=vt220.
Enter copy mode with C-a [ (assuming default C-a escape)
Try to use cursor keys.
Observe copy mode aborted.

>Fix:
Change is2 to use \E[?1l (normal mode) instead of \E[?1h (app mode).