NetBSD Problem Report #55482

From www@netbsd.org  Sat Jul 11 17:37:12 2020
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Date: Sat, 11 Jul 2020 17:37:11 +0000 (UTC)
From: jnaman806@gmail.com
Reply-To: jnaman806@gmail.com
To: gnats-bugs@NetBSD.org
Subject: [libcurses] slk_restore() does not restore the slk screen 
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>Number:         55482
>Category:       lib
>Synopsis:       [libcurses] slk_restore() does not restore the slk screen
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    lib-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 11 17:40:00 +0000 2020
>Closed-Date:    Mon Jun 28 07:27:05 +0000 2021
>Last-Modified:  Mon Jun 28 07:27:05 +0000 2021
>Originator:     Naman Jain
>Release:        NetBSD 9.0
>Organization:
IIT Kanpur
>Environment:
NetBSD localhost 9.0 NetBSD 9.0 (GENERIC) #0: Fri Feb 14 00:06:28 UTC 2020  mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
slk_restore() always returns ERR and hence soft label keys are not restored without doing an explicit refresh.
>How-To-Repeat:
#include <curses.h>
#include <assert.h>

int main() {

    slk_init(0);
    initscr();
    slk_set(1, "first", 0); 
    slk_refresh();
    getch();

    slk_clear();
    slk_refresh();
    getch();

    int err = slk_restore();
    assert(err == OK);  // this assertion fails

    getch();
    endwin();
    return 0;
}

>Fix:
This is probably due to the last label. If this loop is run for only 7/8 labels (https://github.com/NetBSD/src/blob/d889a17013661731f516efa8105dce1e145ffcbe/lib/libcurses/slk.c#L829), it executes well and restores successfully. So, the problem is related to the handling of the last character.

>Release-Note:

>Audit-Trail:

State-Changed-From-To: open->closed
State-Changed-By: blymn@NetBSD.org
State-Changed-When: Mon, 28 Jun 2021 07:27:05 +0000
State-Changed-Why:
slk handling has been fixed.  The assertion in the example code no longer
fires.


>Unformatted:

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