Console output gets messed up after GetCursorPosition is called, if application has been started with "dotnet run".

[perjahn]

Description

• In Linux, output of console gets messed up after abrupt exit, if application has called Console.GetCursorPosition.
• Reproduce: Create a console app that is calling Console.GetCursorPosition and then waits in a loop. Start application with "dotnet run", and then break the application using Ctrl+C.
• After the .net/c# application has quit, text output in terminal gets disabled.

Configuration

• Using dotnet 6.0.400.
• Native Kubuntu 22.04 and Docker (mcr.microsoft.com/dotnet/sdk) on both Macos and Linux.
• Architecture x64 and arm64.
• Appear to be specific to linux, b/c it works well on native terminals in Macos (arm64).

Regression

Haven't tested with older dotnet versions than 6.0, but 6.0.200 has the same problem.

Example application (that disables console output after Ctrl+C)

class Program
{
    public static void Main()
    {
        var pos = System.Console.GetCursorPosition();
        while (true) { }
    }
}

Another example application (that also disables console output after exit)

class Program
{
    public static void Main()
    {
        var pos = System.Console.GetCursorPosition();
        System.Environment.FailFast(string.Empty);
    }
}

Project file

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>
</Project>

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Issue Details

---

Description

• In Linux, output of console gets messed up after abrupt exit, if application has called Console.GetCursorPosition.
• Reproduce: Create a console app that is calling Console.GetCursorPosition and then waits in a loop. Start application with "dotnet run", and then break the application using Ctrl+C.
• After the .net/c# application has quit, text output in terminal gets disabled.

Configuration

• Using dotnet 6.0.400.
• Native Kubuntu 22.04 and Docker (mcr.microsoft.com/dotnet/sdk) on both Macos and Linux.
• Architecture x64 and arm64.
• Appear to be specific to linux, b/c it works well on native terminals in Macos (arm64).

Regression

Haven't tested with older dotnet versions than 6.0, but 6.0.200 has the same problem.

Example application (that disables console output after Ctrl+C)

class Program
{
    public static void Main()
    {
        var pos = System.Console.GetCursorPosition();
        while (true) { }
    }
}

Another example application (that also disables console output after exit)

class Program
{
    public static void Main()
    {
        var pos = System.Console.GetCursorPosition();
        System.Environment.FailFast(string.Empty);
    }
}

Project file

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>
</Project>

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

[adamsitnik]

Hi @perjahn

It looks like you have hit issue #64166, which was already fixed in .NET 7 and is currently being backported to .NET 6 (#64985). The fix is going to be released very soon as part of .NET 6.0.9.

Is there any chance you could try reproducing it with .NET 7?

[perjahn]

Yes, it's reproducible with .net7. I've tested with the latest mcr.microsoft.com/dotnet/nightly/sdk docker image, and using TargetFramework net7.0. Running this image on both macos and kubuntu.
Kubuntu/x64 had dotnet 7.0.0-rc.1.22409.3 in the docker image and Macos/arm64 had dotnet 7.0.100-rc.1.22415.4 in the docker image. Same problem when running a console app with "dotnet run" and exiting it abruptly. :(

[adamsitnik]

@perjahn thank you for verification!

@tmds is there any chance you could take a look?

[tmds]

I can't reproduce this on Fedora using .NET 7.
When I terminate the dotnet run using Ctrl+C the console echo is working.

When I do the same thing in a container, it also works.
I start my container using podman run -ti mcr.microsoft.com/dotnet/nightly/sdk and then use these commands:

dotnet new console -o /tmp/console
cd /tmp/console
cat >Program.cs <<EOF
class Program
{
    public static void Main()
    {
        var pos = System.Console.GetCursorPosition();
        while (true) { }
    }
}
EOF
dotnet build
dotnet run

Are these steps similar to what you are doing with docker?

For the System.Environment.FailFast(string.Empty); the terminal doesn't get reset.
afaik it has been like this for all .NET versions.