Console output mangled upon reaching scroll

[erichiller]

I'm using Powershell inside ConEmu client side, but I've tried the same set of attempts in vanilla cmd.exe

I ran through TTY-PTY-support-in-Windows-OpenSSH and made sure I:

• tried both cmd.exe and ConEmu
• set $env:term="xterm" // set term=xterm respectively and ensured it was set on the connected to server session as well with %term% and ensuring I receive xterm back
• set $env:SSH_TERM_CONHOST_PARSER=0 // set SSH_TERM_CONHOST_PARSER=0

Server Side

OpenSSH_7.6p1, LibreSSL 2.5.3

# Script module or binary module file associated with this manifest
ModuleToProcess = 'OpenSSHUtils.psm1'

# Version number of this module.
ModuleVersion = '1.0.0.1'

Server OperatingSystem: Windows 10 Pro, 15063.674 (Build 1703)

Client OperatingSystem: Windows 10 Pro, 14393.1770 (Build 1607)

What is failing: Terminal output is extremely mangled once the screen edge is reached and scroll has occurred. I actually didn't even realize that it took this to occur until writing this report. Of course my first thought is something with the scrollback buffer, but my settings are in accordance with the wiki:

and when using conemu side

Expected output:

Actual output

[JonathanHolvey]

I've also experiencing this problem with extra lines in the output, as well as extra whitespace being printed between input characters, when connecting to a OpenSSH-Win32 server on Windows 7:

These clients I've had success with:

• OpenSSH-Win32 in cmd.exe or ConEmu on Windows
• GNU OpenSSH in Terminal on Ubuntu

These clients have problems:

• GNU OpenSSH in cmd.exe or ConEmu on Windows
• JuiceSSH on Android

[bagajjal]

@JonathanHolvey - Did you check your "Screen Buffer width and Window Size" > 90.
please go through https://github.com/PowerShell/Win32-OpenSSH/wiki/TTY-PTY-support-in-Windows-OpenSSH.

What win32-openssh version are you using? Is it repro all the time?

[JonathanHolvey]

Yeah, I did read through that wiki page before posting. Everything seems to be in order, however the issue persisted. I was running Win32-OpenSSH version 1.0.0.2018.02.02.

In the end I removed Win32-OpenSSH (after forcibly removing the sshd service), and installed MSYS2, configuring the sshd server using this script instead. This works well for me since I work with Linux a lot and use Bash as my shell on Windows.

[dwatley]

@bagajjal Just want to add I can reproduce this as well.

Server: OpenSSH-Win64 v1.0.0.0
Client: Windows 10 1709, ssh.exe included with git from Git SCM: OpenSSH_7.6p1, OpenSSL 1.0.2l 25 May 2017

Did the xterm, buffer settings and SSH_TERM_CONHOST_PARSER bits. Can easily reproduce it every single session. Not an issue in PuTTY or Chrome SSH App. Happy to help debug. Should also note that this doesn't affect the ssh.exe included with OpenSSH-Win64.

Output:

[bagajjal]

@dwatley - ssh.exe included with git doesn't run.

This might be a git ssh.exe problem as it's not seen on putty, Chrome SSH App and OpenSSH-Win64.

[dwatley]

@bagajjal Works for me...

C:\Program Files\Git\usr\bin>.\ssh.exe -V
OpenSSH_7.3p1, OpenSSL 1.0.2j  26 Sep 2016

Multiple people have reported the issue, I think it may be cygwin based ssh builds potentially?

[JonathanHolvey]

JuiceSSH has the same issue when connecting to a Win32-OpenSSH server, so it's not just cygwin.

[dwatley]

@bagajjal - Are you still having trouble reproducing this?

[dwatley]

@bingbing8 @bagajjal - Ping again. Is this in line for next release or is it not yet reproducible for you?

[bagajjal]

@dwatley - Starting from windows 10 October 2018 update, we are going to use conpty supported provided by the Microsoft console team at server side. A bunch of serverside console rendering issues will be resolved including this.

Having said that, we still need to investigate this for down level OS. Fix for downlevel OS is not aimed for next release.

[bagajjal]

This should be fixed by now in windows 10.
For windows 10 below, we provide only basic support.