access path to the project from a crate's build script

[lucasfernog]

I'm writing a library that needs to access the CARGO_MANIFEST_DIR from the app that uses it, is that possible? The objective is read application assets at compile time.

[ehuss]

I'm not sure I understand the question. You can can call std::env::var("CARGO_MANIFEST_DIR") from a build script to get the project directory (whichever project is using the build script).

[lucasfernog]

When cargo starts building my crate (let's name it my-tool), it assigns the CARGO_MANIFEST_DIR environment variable to the path of this crate's manifest (e.g. /path/to/my-tool). What I'd like to know is the path of the manifest of the crate that's using my-tool as a dependency (let's name it my-app).

Is the only option here to force the my-app/build.rs to call my-tool/build.rs?

[ehuss]

Ah, I think I see what you mean. No, dependencies do not have any information about the packages that depend on it. Your my-app/build.rs would need to specy my-tool as a build dependency and interact with it via its API. Perhaps an analogous example is the cc crate where you load it as a build dependency, and then pass relative paths into it.

[lucasfernog]

Alright, thank you for the help!