How to debug build.rs file?

[ZhaoXiangXML]

I'm trying to debug a build.rs script in vscode, I tried with the following config:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "lldb",
            "request": "launch",
            "name": "build",
            "cargo": {
                "args": [
                    "build",
                    "-vv"
                ],
                "filter": {
                    "name": "physx-sys",
                    "kind": "lib"
                }
            },
        }
    ]
}

However the breakpoints did not hit.

[vadimcn]

Cargo is not executed under the debugger. Try this.

[Sewer56]

There may be some extra steps involved in more modern Rust versions, it seems like the source file isn't being picked up.
Possible to breakpoint via std::intrinsics::breakpoint();, but you only get assembly.

[Sewer56]

Ah, okay. Figuring this out was non-trivial, took 40 mins or so, because this knowledge is niche.

[profile.dev.build-override]
debug = true

You need to disable optimisations for the build to get the breakpoint to work.
It's missing either symbols, or is too optimized.