Re: lib/58282: Sysinst terminal output size increased because curses

[Brett Lymn <blymn%internode.on.net@localhost>]

The following reply was made to PR lib/58282; it has been noted by GNATS.

From: Brett Lymn <blymn%internode.on.net@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: lib-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost,
        Andreas Gustafsson <gson%gson.org@localhost>
Subject: Re: lib/58282: Sysinst terminal output size increased because curses
Date: Tue, 28 May 2024 16:48:48 +0930

 On Sun, May 26, 2024 at 02:20:02AM +0000, Valery Ushakov wrote:
 > The following reply was made to PR lib/58282; it has been noted by GNATS.
 > 
 > From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
 > To: gnats-bugs%netbsd.org@localhost
 > Cc: Brett Lymn <blymn%NetBSD.org@localhost>
 > Subject: Re: lib/58282: Sysinst terminal output size increased because curses
 > Date: Sun, 26 May 2024 05:16:20 +0300
 > 
 >  [cc'ing Brett]
 >  
 >  makech() in refresh.c has a block of code with the comment:
 >  
 >    Work out if we can use a clear to end of line.  If we are using
 >    color then we can only erase the line if the terminal can erase to
 >    the background color.
 >  
 >  it uses (for the HAVE_WIDE case, which is the defautl) the helper
 >  function _cursesi_celleq() that also checks if "attr" is the same, but
 >  the next test in the condition narrows the attr comparison to
 >  attr_mask.  That looks suspicious.
 >  
 
 Having a look at the output all the spam comes from the foreground and
 background colour being set for each cell.  Running from memory the
 narrowing to attr in that section of code is deliberate to force the
 update of the background colour because the actual screen will not have
 changed but the virtual screen image will match the update screen image
 so the background will not be set.  That secion of code caused me
 considerable pain during the rolotill - I am not saying it is 100%
 correct but it does have the correct effect and there was a net decrease
 in output in the atf test captures.
 
 The old code output is more compact because it didn't actually do the
 setting properly so colour based curses applications were not working
 correctly.  The whole rototill was kicked off by someone rasing about a
 bug in a pkgsrc program that was not setting the colours correctly.
 
 >  PS: While there...
 >  
 >  static __LDATA blank; probably should not be static.
 >  
 
 Yes, probably.
 
 >  And for the love of goodness, please, can we keep the parens balanced
 >  inside/outside ifdefs? :)
 >  
 
 That would be most excellent - I am probably guilty of that one :(
 
 -- 
 Brett Lymn
 --
 Sent from my NetBSD device.
 
 "We are were wolves",
 "You mean werewolves?",
 "No we were wolves, now we are something else entirely",
 "Oh"