Does not work correctly in procedural macros called from examples

[DCNick3]

Suppose we have a library crate smol-lib.

When the library is called in context of an example for this library (i.e. smol-lib/examples/smol.rs) trying to look up the name of the same library (smol-lib), this library resolves that the crate is itself.

This makes sense, but, unfortunately, doesn't correspond to the way you would use the crate from an example: you would not write use crate::SmolStruct as inside the library code, but rather use smol_lib::SmolStruct, the same way as you would in a downstream crate.

This is problematic, because it doesn't allow to write examples for the repo using macros and, at the same time, using macros both inside and outside of smol-lib.

Probably some logic should be added to handle the examples case, not sure how it could be done though

[DCNick3]

Seems quite similar to the problem in #10, but there doesn't seem to be the same magic env var like CARGO_TARGET_TMPDIR described at https://doc.rust-lang.org/cargo/reference/environment-variables.html

[bkchr]

Seems quite similar to the problem in #10, but there doesn't seem to be the same magic env var like CARGO_TARGET_TMPDIR described at https://doc.rust-lang.org/cargo/reference/environment-variables.html

Maybe there exists something similar.

[ModProg]

You can use CARGO_CRATE_NAME.

I'm using this and it works as long as you don't name any of your examples the same as your crate:

let htmx = match (
    proc_macro_crate::crate_name("htmx"),
    std::env::var("CARGO_CRATE_NAME").as_deref(),
) {
    (Ok(FoundCrate::Itself), Ok("htmx")) => quote!(crate),
    (Ok(FoundCrate::Name(name)), _) => {
        let ident = Ident::new(&name, Span::call_site());
        quote!(::#ident)
    }
    _ => quote!(::htmx),
};

Only issue is, rust-analyzer currently has a bug: rust-lang/rust-analyzer#15572

[ModProg]

So it turns out this workaroud doesn't work for doctests, because those compile with the same crate name.

[ModProg]

I found a solution, that basically allows using ::crate_name inside your crate in place of crate:

You can use extern crate self as my_crate_name; to make ::my_crate_name work even inside your own crate.

by bjorn3 on zulip