Diagnostics missing due to wrong paths being joined

[aldanor]

Interesting, in one of workspaces I see completions, auto-formatting works, but no diagnostics. Looking at rust-analyzer logfile, there's errors like:

ERROR flycheck 0: File with cargo diagnostic not found in VFS: file not found: workspace-dir/foo/bar/src/x.rs
ERROR flycheck 0: File with cargo diagnostic not found in VFS: file not found: workspace-dir/foo/foo/src/y.rs

whereas the actual layout is

workspace-dir/foo/src/y.rs
workspace-dir/bar/src/x.rs

(I'm working on crate foo that depends on bar, within the workspace, and for some reason everything is erroneously prefixed with its root path 'foo'; however it's a [package] whereas there's root Cargo.toml in workspace-dir with workspace members).

[aldanor]

@ethowitz Same thing happening in another monorepo workspace.

2025-10-28T19:25:14.072332Z ERROR flycheck 0: File with cargo diagnostic not found in VFS: file not found: /path/to/repo/crates/foo/bar/crates/foo/bar/src/lib.rs

This is a large monorepo workspace with root Cargo.toml at /path/to/repo and a specific crate bar, member of that workspace, with its manifest at /path/to/repo/crates/foo/bar/Cargo.toml.

[aldanor]

After a bit of testing, seems it's caused by #38 if you don't have invocationStrategy: 'once' in your RA lsp config 🤔

[ethowitz]

@aldanor Hiya! Yeah, I had updated the README to reflect the new requirement that check.invocationStrategy needs to be set to "once", but unfortunately there's not a great way to surface this new requirement. Definitely open to suggestions if you can think of a good way to communicate this to anyone already using the crate :)

For some additional context, I made the change in #38 to fix an issue where always reporting the buildfile to be the workspace Cargo.toml caused rust-analyzer to get confused and "unindex" crates when opening/closing files between them (e.g. Opening a file in crate A followed by opening a file in crate B led to rust analyzer "forgetting" everything it knew about crate A. When returning to the file in crate A, LSP features were no longer present, so autocompletion/symbol search/etc. wouldn't work).

Does setting check.invocationStrategy to "once" completely resolve the issue for you? Have you noticed any other strange behavior?

[aldanor]

Yea - after testing it a little bit more on the latest main with invocationStrategy=once, it does seem to work I think, cannot tell if there's any artifacts.

[ethowitz]

Sounds good! I'm gonna close this for now, but feel free to reopen if you notice any more issues :)