C# - #IP1 Recived, Expected get extra "$ "

Challenges
1

I’m stuck on Stage #IP1.

I’ve tried to follow working code examples, chatting with ChatGPT and Co-Pilot but i just cant seam to find the problem that is causing this error.

Here are my logs:

[compile]   Determining projects to restore...
[compile]   All projects are up-to-date for restore.
[compile]   codecrafters-shell -> /tmp/codecrafters-build-csharp/codecrafters-shell.dll
[compile] 
[compile] Build succeeded.
[compile]     0 Warning(s)
[compile]     0 Error(s)
[compile] 
[compile] Time Elapsed 00:00:04.23
[compile] Moved ./.codecrafters/run.sh → ./your_program.sh
[compile] Compilation successful.
[tester::#IP1] Running tests for Stage #IP1 (Run a program)
[tester::#IP1] [setup] export PATH=/tmp/quz:$PATH
[tester::#IP1] [setup] Available executables:
[tester::#IP1] [setup] - custom_exe_3579
[tester::#IP1] Running ./your_program.sh
[your-program] $ custom_exe_3579 Emily
[your-program] $ Program was passed 2 args (including program name).
[tester::#IP1] Output does not match expected value.
[tester::#IP1] Expected: "Program was passed 2 args (including program name)."
[tester::#IP1] Received: "$ Program was passed 2 args (including program name)."
[your-program] Arg #0 (program name): /tmp/quz/custom_exe_3579
[your-program] Arg #1: Emily
[your-program] Program Signature: 8866694463
[tester::#IP1] Assertion failed.
[tester::#IP1] Test failed (try setting 'debug: true' in your codecrafters.yml to see more details)

And here’s a snippet of my code:

_paths = Environment.GetEnvironmentVariable("PATH")?.Split(':') ?? [];

private static void Repl()
{
    Console.Write("$ ");
    var userInput = Console.ReadLine();
    RunCommand(userInput);
}

private static void RunCommand(string? userInput)
{
    if (string.IsNullOrEmpty(userInput))
    {
        return;
    }

    var command = userInput.Split(' ');
    var builtin = command[0];

    if (builtin == "exit")
        Exit(command);
    else if (builtin == "echo")
        Echo(command);
    else if (builtin == "type")
        Type(command);
    else if (ExecutableInPath(builtin, out var location))
        Process.Start(location, string.Join(' ', command[1..]));
    else
        Console.WriteLine($"{userInput}: command not found");
}

private static bool ExecutableInPath(string arguments, out string location)
{
    location = string.Empty;
    foreach (var path in _paths)
    {
        var fullPath = Path.Combine(path, arguments);
        if (File.Exists(fullPath))
        {
            location = fullPath;
            return true;
        }
    }
    return false;
}

If my code snippets isnt sufficient enough I will provide this link to my GitHub.

Any help is greatly appreciated :smiley:
Best Regards,
A fella programmer!

3

Some updates that might be worth taking a look at. I got it “working”, well kinda working.

These are the changes I made :

 else if (ExecutableInPath(builtin, out var location))
 {
     var startInfo = new ProcessStartInfo
     {
         FileName = command[0],
         Arguments = string.Join(' ', command[1..]),
         RedirectStandardOutput = true,
         RedirectStandardError = true,
         UseShellExecute = false,
         CreateNoWindow = true,
     };

     var process = new Process { StartInfo = startInfo };
     process.Start();

     // Print stdout
     Console.Write(process.StandardOutput.ReadToEnd());
     Console.Error.Write(process.StandardError.ReadToEnd());

     process.WaitForExit();
     //Process.Start(location, string.Join(' ', command[1..]));
 }

It might look normal but as the “FileName” I now use command[0] instead of the “location” variable. This means that instead of the full path it now uses only the file name, for example “custom_exe_5370” instead of “/tmp/foo/custom_exe_5370”.

I think that this is wrong since im running windows and C# from my knowledge needs the entire path in order to open a program not only the name. Am I wrong here or is this the correct solution?

5

I wrote mine in C for both Windows and Linux, not C# so the following may contain errors. But, neither C# nor Windows needs the full path.

From a cursory glance, it looks like Process.Start on Windows uses CreateProcess (C winapi function) with ApplicationName=NULL but composes an CommandLine argument. This is one of 3 ways to use CreateProcess and in this case CreateProcess takes the first token to resolve the path, so it can be absolute, or just an extensionless name. It looks this up in the current directory, Windows directories, and the PATH locations.

On Linux it resolves the path quite close, but does not use “predefined OS” search like on Windows: runtime/src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs at main · dotnet/runtime · GitHub . When it resolves the path if you give an “rooted” path (which I guess means start with /) then it uses exactly that. Otherwise, it looks like it tries the currently executing programs folder, then the current working directory, and finally PATH folders.

As whether it is right? I think the only important thing is that argv[0] should be whatever was written. So myscript.sh might live in /home/user/myscripts/myscript.sh (assuming myscripts on PATH) but if the only myscript.sh 123 was the shell command then argv[0]=myscript.sh IMO. And the default cases above by C# looks like they handle it.

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