search

rust-lang / cargo

The Rust package manager
https://doc.rust-lang.org/cargo
Apache License 2.0
12.66k stars 2.41k forks source link

Environment variable for Cargo Workspace #3946

Open Ygg01 opened 7 years ago

Ygg01 commented 7 years ago

T-cargo notes:

A CARGO_RUSTC_CURRENT_DIR is added as a nightly only environment variable. See https://github.com/rust-lang/cargo/issues/3946#issuecomment-1832514876. Seek for feedback.

Hi, while working on using workspace in html5ever, I've ran into issue of needing the CARGO_WORKSPACE directory, and being unable, to find it. What I resorted to is essentially, &Path(cargo_manifest).join("..") which feels hacky.

Could CARGO_WORKSPACE be added as environment variable? I'm not sure what it should be when there is no workspace defined, I assume it should either return Err or default it to CARGO_MANIFEST_DIR.

Sidenote I'm willing to work on this issue, if I could get quick pointers, to what I need to do.

epage commented 3 months ago

@bukowa Making file! usable at runtime is one of the use cases we've been working towards with the unstable CARGO_RUSTC_CURRENT_DIR env variable. There has been debate between Cargo and Libs on which should solve the problem and we need to work to resolve it.

epage commented 3 weeks ago

From #13644

Discussed this with @Amanieu at RustConf about this.

In stepping through the use cases, he is now leaning towards file_absolute!(). This potentially would warn or error if trim paths is enabled.

file! documentation should be updated to either

* unspecified and should only be used for diagnostic output and not for programmatic usage

* specified precisely.

This might need to go through compiler (MCP) and libs-api (ACP)...

As we work towards that, we'll need to remove CARGO_RUSTC_CURRENT_DIR.

Another thought I had was that we could change CARGO_RUSTC_CURRENT_DIR to always be CARGO_MANIFEST_DIR if we fixed the rendering if paths from compiler errors. However, this would likely make panic messages confusing.