ProcMacroSrv executed outside of workspace directory

[mattsse]

rust-analyzer version: (eg. output of "Rust Analyzer: Show RA Version" command)
rust-analyzer version: 02904e9 2022-02-14 stable

rustc version: (eg. output of rustc -V)
rustc 1.58.1 (db9d1b20b 2022-01-20)

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTUP_HOME or CARGO_HOME)

It seems like during proc-macro expansion in ProcMacroSrv::expand the task's current dir is not the workspace directory.
I'm not sure how to debug this properly but what I suspect is happening is that the cwd and env vars of the ExpandMacro are not the workspace and workspace env vars. so that, if a proc-macro that expands depending on CARGO_MANIFEST_DIR and expects this path to point to the current workspace, it can generate different token trees for RA inside ProcMacroSrv.

[lnicola]

I don't think rustc guarantees any working directory. But IIUC, this should have been implemented in #11353.

[mattsse]

Right, this rather concerns the env vars, however the cwd also appears to set to an imported crate.
and since CARGO_MANIFEST_DIR is set to an imported crate and not the current workspace, Rust Analyzer: Expand macro recursively shows the code that was expanded while not being in the current workspace.

#11353 seems to be related, but not sure if that's already included in rust-analyzer version: 02904e9 2022-02-14 stable?

[lnicola]

Yeah, #11353 should be included in that version.

[Veykril]

Just looked into this and this seems to work fine?

#[proc_macro]
pub fn foo(ts: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let ct_env = env!("CARGO_MANIFEST_DIR");
    let rt_env = format!("{:?}", std::env::var("CARGO_MANIFEST_DIR"));
    quote::quote!((#ct_env, #rt_env)).into()
}

expands to the same stuff in r-a and rustc. So unless we get more specifics I'll close this for the time being.