Workaround for Window 10 conhost bug in 170819 broke Vim colors

[GrzegorzKozub]

Versions

ConEmu build: 170819 x64
OS version: Windows 10 Pro version 1703 build 15063.632 x64
Used shell version: cmd, powershell

Problem description

I noticed a regression between builds 170814 and 170819.

Terminal version of Vim 8 displays incorrect colors when switching modes and displaying error messages. This happens with default ConEmu settings and I did not find any option that would remedy the issue. As for Vim, the only non-default option I'm setting is highlight EndOfBuffer ctermfg=BG to be able to quickly reproduce the problem. This setting aims to hide tildas below Vim's buffer end.

The problem is caused by commit 4382393. I confirmed that hypothesis by reverting just that single commit on master, building in Release with x64 flavour and seeing the issue had disappeared.

Steps to reproduce

1. Place highlight EndOfBuffer ctermfg=BG in %home%\vimfiles\vimrc
2. Run ConEmu 170819 or newer
3. Run terminal Vim 8 in that ConEmu session via vim.exe
4. Switch Vim modes, type something, try quitting without saving changes

Actual results

5. As soon as you hit the first key in Vim, tildas are back
6. When you try to quit with a dirty buffer, error message color spills into the space after the end of Vim's buffer

Expected results

5. Tildas are hidden
6. Error message color remains in Vim's status line

Additional files

Here's the scenario with plain cmd.exe where the problem does not appear:

Same for build 170814, no issues:

And here's the recording of the regression described above captured from build 170819:

Now, I apologise if this is a manifestation of another, already reported issue, but I don't know C++ to be able to tell. Let me know if I can be of any help.

Thanks!

[GrzegorzKozub]

Confirmed as fixed in version 171025. Thanks!