Process.Start() doesn't work in netcoreapp2.1 but good in 2.0

[LincolnYang1]

Process.Start() doesn't work in netcoreapp2.1 but good in 2.0

i have below simple code to demo the issue, it works well in netcoreapp2.0 but not in netcoreapp2.1
system is aws cloud,
Linux version 4.9.81-35.56.amzn1.x86_64 (mockbuild@gobi-build-64010) (gcc version 7.2.1 20170915 (Red Hat 7.2.1-2) (GCC) ) #1 SMP Fri Feb 16 00:18:48 UTC 2018

        static void Main(string[] args)
        {
            var fileName = args[0];
            Console.WriteLine($"{fileName} : exists: {File.Exists(fileName)}");
            
            var processStartInfo = new ProcessStartInfo(fileName)
            {
                Arguments = "--info",
                UseShellExecute = true
            };
            var process = Process.Start(processStartInfo) ?? throw new Exception("failed to start process");
            process.WaitForExit();
        }

run-time parameter is, /opt/dotnet/dotnet is the dotnet executable path
dotnet testapp.dll /opt/dotnet/dotnet

project file is

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.0</TargetFramework>
    <RuntimeIdentifiers>rhel.7.4-x64</RuntimeIdentifiers>
  </PropertyGroup>
</Project>

Build and Publish

if change project to 2.0, build and publish with dotnet core 2.0, it works fine.

dotnet build --runtime rhel.7.4-x64
dotnet publish --runtime rhel.7.4-x64 -c Release --framework netcoreapp2.0

but if change to 2.1
dotnet build --runtime rhel.7.4-x64
dotnet publish --runtime rhel.7.4-x64 -c Release --framework netcoreapp2.1

it throw error, there is Win32Exception throw out.

Unhandled Exception: System.ComponentModel.Win32Exception: No such file or directory
at System.Diagnostics.Process.StartCore(ProcessStartInfo startInfo)
at System.Diagnostics.Process.Start()
at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
at testapp.Program.Main(String[] args) in source\repos\testapp\testapp\Program.cs:line 14

[LincolnYang1]

find some clue,
in 2.0, it use "/bin/sh" as shell, source: https://github.com/dotnet/corefx/blob/release/2.0.0/src/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs

private bool StartCore(ProcessStartInfo startInfo)
        {
            string filename;
            string[] argv;

            if (startInfo.UseShellExecute)
            {
                if (startInfo.RedirectStandardInput || startInfo.RedirectStandardOutput || startInfo.RedirectStandardError)
                {
                    throw new InvalidOperationException(SR.CantRedirectStreams);
                }

                const string ShellPath = "/bin/sh";

                filename = ShellPath;
                argv = new string[3] { ShellPath, "-c", startInfo.FileName + " " + startInfo.Arguments};

but in 2.1, it uses one of "xdg-open", "gnome-open", "kfmclient" to open file, this make "UseShellExecute" behave totally not same as 2.0
src: https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.Process/src/System/Diagnostics/Process.Linux.cs

        private string GetPathToOpenFile()
        {
            string[] allowedProgramsToRun = { "xdg-open", "gnome-open", "kfmclient" };
            foreach (var program in allowedProgramsToRun)
            {
                string pathToProgram = FindProgramInPath(program);
                if (!string.IsNullOrEmpty(pathToProgram))
                {
                    return pathToProgram;
                }
            }
            return null;
        }

[omajid]

For your case, you probably want to set UseShellExecute to false to run dotnet --info, or pretty much any other program. Unless you actually care about /bin/bash being used to invoke it? I can't see how that would be useful in your example.

[LincolnYang1]

thanks for reply,
sample code just to demo inconsistency of UseShellExecute between 2.0 and 2.1, the actual code is more complicate and need UseShellExecute 2.0 feature,
after migrate to 2.1 it suddenly doesn't work, since "xdg-open", "gnome-open", "kfmclient" are not really shell, like /bin/sh and /bin/bash , does it make sense to obey its original definition?

[omajid]

@LincolnYang1 I suggest bringing it up here: https://github.com/dotnet/corefx/issues/24704. That's an ongoing discussion about this exact same issue.

In the meantime, can you invoke /bin/bash explicitly?

[Petermarcu]

Yes, lets move this discussion to dotnet/corefx#24704. I'll close this one here.