3.1.2: possible Cygwin DLL console or pty bug when forwarding the stdout to less within the Windows-Console (cmd.exe Win10 build 1809, 1903, 1909)

Takashi Yano takashi.yano@nifty.ne.jp
Sun Feb 16 02:19:00 GMT 2020


On Sat, 15 Feb 2020 20:51:04 +0900
Takashi Yano wrote:
> On Fri, 14 Feb 2020 12:04:16 +0100
> cygwin@mg13.computerpost.de wrote:
> > Since 3.1.1 (including current 3.1.3-snapshot) I have the problem
> > that escape sequences (single character, not the three letters "ESC", 
> > plus "[...m") suddenly appear inside less,
> > and when I leave less, the cmd.exe console displays escape sequences at 
> > the cursor up (down, left, right) and does not respond correctly to cls.
> > It seems that less initializes the console and while less prints 
> > something, another program deinitializes the console.
> > With 3.0.7 cygwin1.dll it works fine. (But I want xterm256-color from 
> > 3.1.x cygwin1.dll.)
> > 
> > Here simple examples:
> > 
> > 1)
> > C:\Users\slasch>ls C:\Windows | less -E +G
> > 
> > C:\Users\slasch>^[[A
> > 
> > 
> > 2)
> > C:\Users\slasch>ls C:\cygwin64\bin | less  # then press G and q
> > ...
> > -rwxr-xr-x 1 slasch slasch    1940 Aug 26  2016 zcat
> > -rwxr-xr-x 1 slasch slasch    1665 Aug 26  2016 zcmp
> > -rwxr-xr-x 1 slasch slasch    5667 Aug 26  2016 zdiff
> > -rwxr-xr-x 1 slasch slasch      29 Aug 26  2016 zegrep
> > -rwxr-xr-x 1 slasch slasch      29 Aug 26  2016 zfgrep
> > -rwxr-xr-x 1 slasch slasch    2038 Aug 26  2016 zforce
> > -rwxr-xr-x 1 slasch slasch    7444 Aug 26  2016 zgrep
> > -rwxr-xr-x 1 slasch slasch    2154 Aug 26  2016 zless
> > -rwxr-xr-x 1 slasch slasch    1816 Aug 26  2016 zmore
> > -rwxr-xr-x 1 slasch slasch    4392 Aug 26  2016 znew
> > [K[?1l>[?1049l[23;0;0t7[3g[1;9HH[1;17HH[1;25HH[1;33HH[1;41HH[1;49HH[1;57HH[1;65HH[1;73HH[1;81HH[1;89HH[1;97HH[1;105HH[1;113HH8
> > C:\Users\slasch>^[OA^[OA
> > 
> > 
> > 3) # other PC other commands (Strawberry-Perl with "cmd.exe dir" stdout 
> > forwarded to less) to show the single "escape character"(see attachment)
> > total 320
> > drwxr-xr-x+ 1 foo    foo                 0 Feb 13 17:40 .
> > drwxr-xr-x+ 1 foo    foo                 0 Feb 13 17:42 ..
> > -rwxr-xr-x  1 sadmin Administratoren 35147 Apr 30  2019 COPYING
> > -rwxr-xr-x  1 sadmin Administratoren  1458 Apr 30  2019 CYGWIN_LICENSE
> > -rw-r--r--  1 foo    foo              2045 Dec 16  2017 
> > _autorebase.README
> > -rw-r--r--  1 foo    foo              2653 Apr  5  2013 
> > alternatives.README
> > -rw-r--r--  1 foo    foo              1694 Jul  9  2013 autoconf.README
> > -rw-r--r--  1 foo    foo              2096 Jul  9  2013 
> > autoconf2.1.README
> > -rw-r--r--  1 foo    foo              1806 Jul 29  2013 
> > automake1.9.README
> > -rw-r--r--  1 foo    foo              4227 Apr  1  2019 autossh.README
> > -rw-r--r--  1 foo    foo             17474 Jan 27  2017 bash.README
> > -rw-r--r--  1 sadmin Administratoren  1468 Aug  9  2010 
> > build-docbook-catalog.README
> > -rw-r--r--  1 foo    foo             13113 Feb  3  2017 coreutils.README
> > -rw-rw----  1 foo    foo              1863 Apr 16  2013 ctags-5.8.README
> > -rw-r--r--  1 foo    foo             20685 Jan 28  2015 cygrunsrv.README
> > -rw-r--r--  1 sadmin Administratoren  8136 Apr 30  2019 cygserver.README
> > -rw-r--r--  1 foo    foo              2303 Feb 17  2017 dash.README
> > -rw-r--r--  1 foo    foo              3671 Mar 10  2016 diffstat.README
> > -rw-r--r--  1 foo    foo              2749 Dec  7  2016 diffutils.README
> > -rw-r--r--  1 foo    foo              1965 Oct  3 19:59 dos2unix.README
> > -rw-r--r--  1 foo    foo               626 Oct 31  2014 
> > editrights.README
> > -rw-r--r--  1 foo    foo              4829 Mar 11  2016 findutils.README
> > -rwxr-xr-x  1 foo    foo                 0 Dec 13 09:28 gawk
> > :
> 
> Thanks for the report. However, I cannot reproduce problem 1 and 3.
> I will submit a patch for the problem 2 shortly.

I could reproduce the problem 3 using less with -R option as
suggested by Georg, and found the patch for the problem 2
also solves the problem 3.

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>

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