ConPTY doesn't set KeyEvent::_virtualScanCode for certain characters like : (which bothers GoW less)

[perlmaster]

Environment

Windows 10
Any other software?

# Steps to reproduce

1. Run cmd.exe under windows terminal preview
2. navigate to a directory containing text files
3. Run the command "less -MN *.txt"
4. When you reach the end of the 1st file enter the "less" command ":n" to go to the next file

# Expected behavior
"less" should start displaying the next file.

# Actual behavior
I get the following error message "no previous regular expression". This does not happen when I run less under a cmd.exe session the old fashioned way.

[DHowett-MSFT]

less doesn't ship with Windows, so you're going to need to share exactly which less you are using. Otherwise, we can't exactly debug the issue.

[perlmaster]

according to "less --version" I am running less version 378

[zadjii-msft]

I think @DHowett-MSFT meant more of "are you using wsl's less, cygwin's less, some unknown less.exe?"

[perlmaster]

I downloaded "less" a long time ago. I don't remember exactly where I got it.

The command "less --version" produces the following

less 378
Copyright (C) 2002 Mark Nudelman

less comes with NO WARRANTY, to the extent permitted by law.
For information about the terms of redistribution,
see the file named README in the less distribution.
Homepage: http://www.greenwoodsoftware.com/less

In the documentation I got at the time, there is the following paragraph:

   Copyright (C) 2002  Mark Nudelman

   less is part of the GNU project and is free software.  You
   can redistribute it and/or modify it under  the  terms  of
   either  (1) the GNU General Public License as published by
   the Free Software Foundation; or  (2)  the  Less  License.

Although I have cygwin, I do not use it.

[zadjii-msft]

So the less I have on WSL is just about 100 versions more updated - could you maybe try a newer less version?

zadjii@migrie-slaptop:~$ less --version
less 487 (GNU regular expressions)
Copyright (C) 1984-2016  Mark Nudelman

I can only find posts about sed creating that "no previous regular expression" error, so I'm not really sure how that's getting into less, or how the terminal might be feeding bad characters into it.

What keyboard layout are you using?

[perlmaster]

I must be having a slow day. Who or what is WSL ?

[perlmaster]

Sorry, it just occured to me that WSL == Windows Subsystem for Linux

[perlmaster]

Does anyone know where I can find a compiled binary version of less ? So far the only thing I have found is source code and I have always had issues trying to compile anything that requires the bourne shell to run a script named "configure" which starts the whole build process. On my windows 10 64 bit system I can't get sh.exe to run properly

[DHowett-MSFT]

That's a really good question, honestly. It looks like the GoW project produces binaries of these tools with reasonable frequency, but their terminal emulator bridge leaves a little bit to be desired. Perhaps their less works slightly better than the one you've got?

Sorry, I know it's not much. 😄

[ghost]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment.

[perlmaster]

The GoW version of less did not solve the problem. I am continuing my search for some kind of solution.

[DHowett-MSFT]

That is very good news for us, because now we have learned of a distribution of less that we can use for a repro. Thank you!

What keyboard layout are you using? Standard en-US PC104?

[perlmaster]

I am not sure about the exact specs for my keyboard, but it is definitely en-US. I am unable to determine if it is PC104 , I have checked in the control panels and nothing speaks of PC104

[perlmaster]

just for the record I have the same issue wether I use my laptop keyboard or my wired USB keyboard

[0xd4d]

Try less that's part of Git for Windows

[perlmaster]

I already had git for windows 2.15.0 on my system. I was not aware that it had all those extra executables. It had less version 481. That version of less seems to be working just fine !

That solves my specific issue. Thanks to all who helped !

[DHowett-MSFT]

And we've got a root cause, too!

It looks like some versions of less for windows are checking the scancode of the keyboard key that's pressed, and when that key comes in off a pty (which Windows Terminal, VSCode, Visual Studio, etc. use), that scancode isn't set.

pseudoconsole

↓ wch:0 '\0' mod:Shift (16) repeat:1 vk:16 vsc:42
↓ wch:0 '\0' mod:Shift (16) repeat:1 vk:16 vsc:42
↓ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:0 <--- bad (0)
↓ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:0 <---
↑ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:0 <---
↑ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:0 <---
↑ wch:0 '\0' mod:None (0) repeat:1 vk:16 vsc:42
↑ wch:0 '\0' mod:None (0) repeat:1 vk:16 vsc:42

conhost

↓ wch:0 '\0' mod:Shift (16) repeat:1 vk:16 vsc:42
↓ wch:0 '\0' mod:Shift (16) repeat:1 vk:16 vsc:42
↓ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:39 <--- good (39)
↓ wch:58 ':' mod:Shift (16) repeat:1 vk:186 vsc:39 <--- good (39)
↑ wch:0 '\0' mod:None (0) repeat:1 vk:16 vsc:42
↑ wch:0 '\0' mod:None (0) repeat:1 vk:16 vsc:42

[DHowett-MSFT]

And as a final followup, it's because somewhere deep in the console host, we're doing a "vkey to vsc" translation, but we're providing it a character instead of a vkey. 🤦‍♂

[DHowett-MSFT]

diff --git a/src/types/convert.cpp b/src/types/convert.cpp
index c2049ded9..bc87bab18 100644
--- a/src/types/convert.cpp
+++ b/src/types/convert.cpp
@@ -206,7 +206,8 @@ std::deque<std::unique_ptr<KeyEvent>> SynthesizeKeyboardEvents(const wchar_t wch
                                                        SHIFT_PRESSED));
     }

-    const WORD virtualScanCode = gsl::narrow<WORD>(MapVirtualKeyW(wch, MAPVK_VK_TO_VSC));
+    auto vk = keyState & 0xFF;
+    const WORD virtualScanCode = gsl::narrow<WORD>(MapVirtualKeyW(vk, MAPVK_VK_TO_VSC));
     KeyEvent keyEvent{ true, 1, LOBYTE(keyState), virtualScanCode, wch, 0 };

     // add modifier flags if necessary

[ghost]

🎉This issue was addressed in #3199, which has now been successfully released as Windows Terminal Preview v0.6.2951.0.:tada:

Handy links:

• Release Notes
• Store Download