How do I debug with cargo-aoc

[dantho]

I'm having no luck debugging (using VS Code and ) while running with cargo-aoc. The debugger ignores my break-traps in dayN.rs I'm a bit of a newbie. This should work, right? Is there something in this .vscode launch.json file that's wrong? (I can debug Hello World with a similar setup.)

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "(Windows) Launch",
            "type": "cppvsdbg",
            "request": "launch",
            "program": "${workspaceFolder}/target/debug/advent-of-code-2020.exe",
            "args": [],
            "stopAtEntry": false,
            "cwd": "${workspaceFolder}",
            "environment": [],
            "externalConsole": false
        }
    ]
}

[mjpieters]

cargo aoc generates a new, nested Rust project under target/aoc; the binary you want to run is target/aoc/aoc-autobuild/target/release/aoc-autobuild. This is generated, built and run when you use cargo aoc on the command-line. Make sure you run cargo aoc before debugging; the generated code applies to a single day (by default, the most recent, use the command-line switches to change what day driver is generated).

I opened a feature request (two years ago) to help with debugging by only generating the binary, not also run it (see #64, PR in #69), but neither have seen movement unfortunately.

In the meantime, I use vscode-lldb features to trigger a build and extract the right binary path for the debugger, I don't know if cppvsdbg has something similar. For lldb, don't set program, but set cargo instead, and have it run cargo build --manifest-path target/aoc/aoc-autobuild/Cargo.toml --bin=aoc-autobuild; lldb will extract the right binary and you can then start debugging. This will only work if cargo aoc was run before to generate the nested project.

[dantho]

Thanks for the reply, @mjpieters !

Because of your reply, I finally dug in and got Rust debugging working in VS Code. I tried using whatever debugger I had installed, and the executable you pointed me to. It didn't work. But then I loaded the VSCode Add-in "CodeLLDB", ran its command "LLDB: Generate Launch Configurations from Cargo.toml" and I can now debug my code and my tests!

Love it. Thanks again.

[MaddyGuthridge]

For anyone else that comes across this issue, this is the launch.json that worked for me:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "type": "lldb",
            "request": "launch",
            "name": "Debug current day",
            "cargo": {
                "args": [
                    "build",
                    "--manifest-path=target/aoc/aoc-autobuild/Cargo.toml",
                    "--bin=aoc-autobuild"
                ],
            },
            "args": [],
            "cwd": "${workspaceFolder}"
        }
    ]
}