"CTRL+M" is captured as "Enter" in console app on Linux

[MrM40]

Description

In .Net 6 vb.net Console.ReadKey() read "CTRL+M" as "Enter"

Any other CTRL+ combinations seems to work fine e.g. "CTRL+L":

I worked fine in .net core 2.2

Tried on OpenSUSE 15.3 and Debian 11 Linux boxes (also directly on the VGA/keyb console).
And tested nn these terminals: Kitty and Windows Terminal.

.net runtime installation on the Linux box:

Reproduction Steps

Debug Console.ReadKey() and see what .net interpret the key keystroke CTRL+M

Expected behavior

ConsoleKeyInfo.Modifiers should be Control
and
ConsoleKeyInfo.Key should be M

Actual behavior

Read as Enter

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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Issue Details

---

Description

In .Net 6 vb.net Console.ReadKey() read "CTRL+M" as "Enter"

Any other CTRL+ combinations seems to work fine e.g. "CTRL+L":

I worked fine in .net core 2.2

Tried on OpenSUSE 15.3 and Debian 11 Linux boxes (also directly on the VGA/keyb console).
And tested nn these terminals: Kitty and Windows Terminal.

.net runtime installation on the Linux box:

Reproduction Steps

Debug Console.ReadKey() and see what .net interpret the key keystroke CTRL+M

Expected behavior

ConsoleKeyInfo.Modifiers should be Control
and
ConsoleKeyInfo.Key should be M

Actual behavior

Read as Enter

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	MrM40
Assignees:	-
Labels:	area-System.Console
Milestone:	-

[danmoseley]

Can you try with the latest daily build of .NET 7?

[MrM40]

I will tomorrow....thanks for the suggestion.

[MrM40]

Ohhh....I see I need to reinstall (or at least update) my Visual Studio 2022 for 7.0 support, which I don't dare right now. It's my production PC :-/
If you already have a 7.0 environment up an running, can you make a quick test-project?
Or perhaps just take a quick look in the 6.0 code.....I wouldn't be suppressed if it was just the switch-value for CTRL-M which wasn't updated (I have no clue where to look myself)

[danmoseley]

You do not need to modify VS in any way. Installations of .NET are side by side. See

https://github.com/dotnet/runtime/blob/main/docs/project/dogfooding.md

You will just change the TargetFramework of your test project, by editing it directly.

[adamsitnik]

Hi @MrM40

Every Unix Terminal maps keys pressed by the user to their byte representation that .NET reads via read() sys-call.

The best utility for finding out the mappings is using showkey -a Linux command line tool.

In the following picture I've pressed Enter, Ctrl+J and Ctrl+M:

As you can see, Ctrl+M is just mapped to exactly same byte as Enter (0x0d) by the Terminal. This is a Unix convention; .NET has no control over that. We can't map Ctrl+M to Ctrl+M because it would mean that we would need to map Enter to Ctrl+M as well.

We have rewritten Console.ReadKey for .NET 7 and in #72193 I've listed all limitations:

• Ctrl+M is mapped to Enter with carriage return character (\r)
• Ctrl+J is mapped to Ctrl+Enter with new line character (\n)
• Ctrl+I is mapped to Tab
• Clr+H is mapped to Ctrl+Backspace

This is by design.

[MrM40]

@adamsitnik
Confirmed!
I guess it wasn't work in .NET Core 2.2 after all :-/
Thanks for sharing your wisdom and sorry for the "noise".