node-pty terminals jump to bottom when a .NET Core console app requests for a cursor position

From @tylerl0706 on July 21, 2018 3:13

Environment

• Environment: VSCode and Hyper
• OS version: macOS & Fedora 28

Details

node-pty terminals jump to the bottom when a .NET Core console app requests for a cursor position. In other terminals (iterm, terminal.app), it does not.

This only happens on unix/linux OS’s - Windows works as expected.

This is easily reproducible in PowerShell since it’s built on .NET Core.

Steps to reproduce

1. have PowerShell on unix
2. hit enter a bunch (until the page starts scrolling)
3. run this

while ($true) { $null = [Console]::CursorTop; Start-Sleep 1 }

1. scroll up

Note the use of [Console]::CursorTop which is the cursor query. In .NET Core, this emits the report cursor position ansi escape sequence on unix-like platforms

Actual behavior

The console window jumps down to the prompt

Expected behavior

The console window does not move

Copied from original issue: Microsoft/node-pty#211

[Tyriar]

@tylerl0706 can you clone my fork, checkout 1579_emit_pos_directly and test if this fixes it by running the demo?

[TylerLeonhardt]

@Tyriar sorry for the delay! I was heads down on OneWeek 👍

I can confirm that branch fixes the problem 🎉