cargo: warning: skipping duplicate package `case` found at `~\.cargo\git\checkouts\cargo-..`

Yes, I thought about that too! It does however seem a bit beyond my acceptability knowledge and the current issue’s specific topic: to discuss separately?

@PaulDance https://github.com/rust-lang/cargo/issues/10147

Would it be possible to restrict the warning to situations where the package is actually used? That is, when doing cargo install --git or having a git dependency, only issue a warning if that package was actually part of the selected packages? I suspect that won’t be easy since read_packages is pretty low-level, but I think from a user experience, that is what would be expected. Warning about unrelated packages seems to be a false-positive. Also, forcing people to use a workaround like publish=false does not seem ideal.

I would also expect this to actually be an error in the long-run. In the original issue (#10669), this leads to non-deterministic behavior. A warning just says “something’s broken” and then proceeds doing something random, which doesn’t seem good.

Also, the current warning does not seem to be very helpful (particularly for an end-user who may have no idea where this is coming from, or is not well-versed in cargo). There is no actionable advice given to the user, or any context as to how cargo got into this bind. I would expect in the situation with a git dependency that has a duplicate, it would say something like:

error: multiple packages named `foo` found in git repository 
https://github.com/rust-lang/example for dependency `foo` specified in `path/to/Cargo.toml`
    First instance found at `path/in/repo/Cargo.toml`
    Second instance found at `path/in/repo/other-foo/Cargo.toml`
    A git repository must only contain a single package with the name `foo`.

With similar errors for paths overrides and install --git.

(Without the ability to restrict a git repo to a specific path, the solution of being unique isn’t great, but should be fine in most situations.)

We discussed this in the cargo team meeting and came up with a short term and long-term idea

Short term is to see if we can make the warning only appear when the package is publish = true

There is still the wider problem if packages being looked up that are internal. Ideas

• a breadcrumb file that says “stop recursively walking for path/git sources”
• a new manifest key that says “stop recursing and use workspace lookup rules”