How to debug a file-based app

[newpost]

How to debug a file-based app

In upcoming .NET 10 previews we’re aiming to improve the experience of working with file-based apps in VS Code, with enhnanced IntelliSense for the new file-based directives, improved performance, and support for debugging. At the command line we’re exploring support for file-based apps with multiple files, and ways to make running file-based apps faster.

[DamianEdwards]

Debugging support is currently being worked on. It will be supported in VS Code with the C# and C# Dev Kit extensions and will be tracked as part of dotnet/roslyn#78755

[dabbinavo]

For anyone searching for a solution for this.

This is the workaround I am using till debugging of single file apps is supported natively by the C# Extension.

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "C# Debugger: Current File",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "C#: Build current file",
            "program": "${env:TEMP}/dotnet/runfile/${fileBasenameNoExtension}.dll",
            "cwd": "${fileDirname}",
            "console": "integratedTerminal"
        },
        {
            "name": "C# Debugger: Current File with Arguments",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "C#: Build current file",
            "program": "${env:TEMP}/dotnet/runfile/${fileBasenameNoExtension}.dll",
            "args": "${input:csDebugArgs}",
            "cwd": "${fileDirname}",
            "console": "integratedTerminal"
        }
    ],
    "inputs": [
        {
            "id": "csDebugArgs",
            "type": "promptString",
            "description": "Program arguments (optional, space-separated)",
            "default": ""
        }
    ]
}

tasks.json

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "C#: Build current file",
            "command": "dotnet",
            "type": "process",
            "options": {
                "cwd": "${workspaceFolder}"
            },
            "args": [
                "build",
                "${file}",
                "--output",
                "${env:TEMP}/dotnet/runfile"
            ],
            "problemMatcher": "$msCompile",
            "group": "build"
        }
    ]
}

[DamianEdwards]

@dabbinavo not sure why you need a workaround? Debugging file-based apps is supported in VS Code and should only require hitting F5 or clicking the launch arrow button in the top-right of the editor file tab.

[dabbinavo]

@DamianEdwards Is this also true without the C# DevKit extension?

[DamianEdwards]

@dabbinavo https://github.com/dotnet/vscode-csharp/blob/release/debugger.md

[dabbinavo]

@DamianEdwards Just with C# Extension:

cs-file-based-app.mp4

[DamianEdwards]

@RikkiGibson @jjonescz @claudiaregio I admit I'm not clear on the expectation here, but documentation seems to indicate that debugging with C# extension only (no C#DK) is possible?

[jjonescz]

Yes, you can actually pass a file-based app instead of a project in the dotnet launch configuration like

// .vscode/launch.json
{
    "configurations": [
        {
            "name": "C#: my file launch profile",
            "type": "dotnet",
            "request": "launch",
            "projectPath": "${workspaceFolder}/file.cs"
        }
    ]
}

That should be supported with the base C# extension AFAIK.
Unfortunately, last time I looked, that launch configuration didn't support command line arguments.

[DamianEdwards]

@jjonescz I get this when trying that:

[DamianEdwards]

@jjonescz more experimentation got me to here:

[jjonescz]

Sorry, I was wrong, that also only works with DevKit. It's a way to specify a launch profile in vscode's launch.json instead of relying on debugging just the active file, but not a way to debug without devkit. I should know, I implemented file-based app debugging and I implemented it in the DevKit repository 🤦