lib/51819: curses vs. news/tin display problems

[uwe%NetBSD.org@localhost]

>Number:         51819
>Category:       lib
>Synopsis:       curses vs. news/tin display problems
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 11 01:15:00 +0000 2017
>Originator:     Valery Ushakov
>Release:        NetBSD-6.1
>Organization:
>Environment:
NetBSD pony 6.1_STABLE NetBSD 6.1_STABLE (GENERIC) #13: Thu May 19 03:06:28 MSK 2016  root@:/export/netbsd/cvs/src-release-6/sys/arch/macppc/compile/GENERIC macppc 
>Description:
I see this on my NetBSD 6.1 macppc and I also did a quick test on
NetBSD 7.0.1 i386.  I haven't tried current.

news/tin package is built with curses support by default

  PKG_OPTIONS_GROUP.display=     curses ncurses ncursesw
  PKG_SUGGESTED_OPTIONS=         curses inet6

Unfortunately when built with NetBSD curses (as suggested), it has
display problems.  I haven't tried building the package with ncurses,
but I assume it should work, or someone would have noticed that :).

See below for details.

>How-To-Repeat:
Install news/tin (a binary package will do).  Use it to read news,
e.g. via gmane nntp interface at news.gmane.org.  This mostly works,
but open any article and use arrows down/up to scroll the article a
line at a time.  Observe the display garbled.  I see this both under
screen and wsvt25.

When you scroll down, the ghost of the "--More--" prompt scrolls up.
E.g. you can see something like this at the bottom of the screen:

----8<--------8<----
standards                   1        9       23       33      2m 21d 23:54:08   
toolchain                   8       64       55      127      3m 15d 21:55:17   
xsrc                        4       25       21       50         25d 22:46:599] 
TOTAL                     548     2590     2191     5329  --More--(93%) [55/59] 
                                                          --More--(94%) [56/59] 
                                                          --More--(96%) [57/59] 
                                                          --More--(98%) [58/59] 
                                                            -- Next response --
----8<--------8<----


When you scroll up, the article header scrolls down and disappears
instead of staying where it is.

>Fix:
The workaround I've been using for ages is to add "nocurses" option to

  PKG_OPTIONS_GROUP.display=     nocurses curses ncurses ncursesw

and use that option to build the package.  It will cause configure to be run without --with-screen=... argument and tin will fall back to raw termcap/terminfo display code that works.