lib/54263: curses changes broke sysinst

[martin%NetBSD.org@localhost]

>Number:         54263
>Category:       lib
>Synopsis:       curses changes broke sysinst
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jun 02 11:30:00 +0000 2019
>Originator:     Martin Husemann
>Release:        NetBSD 8.99.42
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD night-owl.duskware.de 8.99.42 NetBSD 8.99.42 (NIGHT-OWL) #672: Fri May 31 18:12:54 CEST 2019 martin%night-owl.duskware.de@localhost:/usr/src/sys/arch/amd64/compile/NIGHT-OWL amd64
Architecture: x86_64
Machine: amd64
>Description:

Some sysinst menus do not display correctly after recent curses changes.
If this is a menuc or sysinst bug, someone please explain what needs to
change there to me ,-)

>How-To-Repeat:

You can reproduce on a running system with shared libcurses, no need to
prepare install media, but it needs a bit of setup:

As root do:

One time preparation:

cd /var/tmp
dd if=/dev/zero of=disk.img seek=6g count=1
vnconfig -c vnd0 disk.img
disklabel -eI vnd0		(just exit the editor)
newfs -O2 vnd0a
mount /dev/vnd0a /mnt
mkdir /mnt/etc
touch /mnt/etc/fstab
umount /mnt

Then to reproduce:

	sysinst

select keyboard type (unchanged) and prefered language, then:

	f: Config menu 
	a: vnd0			(or not "a" if you have other disks around)

You will get a menu like:


 Configure the additional items as needed.


 a: Configure network                                  configure
 b: Timezone                                           UTC
 c: Root shell
 d: Change root password                               ***EMPTY***
 e: Enable installation of binary packages             install
 f: Fetch and unpack pkgsrc                            install
 g: Enable sshd                                        NO
 h: Enable ntpd                                        NO
 i: Run ntpdate at boot                                NO
 j: Enable mdnsd                                       NO
 k: Enable xdm                                         NO
 l: Enable cgd                                         NO
 m: Enable lvm                                         NO
 n: Enable raidframe                                   NO
 o: Add a user
>x: Finished configuring

with the last line (x:) highlighted.

Now move the selection up (depending on keyboard type with arrows, or using
^P for up / ^N for down.

Moving the selection garbles the screen. The drawn highlight bar is 
"duplicated" and the content previously below it is repeated with an y
offset. Plain (unhighlighted) content after two "ups":

                                                                                
 Configure the additional items as needed.                                      
                                                                                
                                                                                
 a: Configure network                                  configure                
 b: Timezone                                           UTC                      
 c: Root shell                                                                  
 d: Change root password                               ***EMPTY***              
 e: Enable installation of binary packages             install                  
 f: Fetch and unpack pkgsrc                            install                  
 g: Enable sshd                                        NO                       
 h: Enable ntpd                                        NO                       
 i: Run ntpdate at boot                                NO                       
 j: Enable mdnsd                                       NO                       
 k: Enable xdm                                         NO                       
 l: Enable cgd                                         NO                       
 m: Enable lvm                                         NO                       
 n: Enable raidframe                                   NO                       
>o: Add a user                                                                  
 x: Finished configuring                                                        
>n: Enable raidframe                                   NO                       
 o: Add a user


This started happening with recent libcurses changes. It still works fine with
a libcurses from ~ May 18, but breaks with a May 26 one.


>Fix:
n/a