As a member of the crates.io team but only expressing my opinion, not that of the team: in general, I'm not opposed to this idea if someone wants to send in the code for it. I'm not sure that the problem it solves is particularly important to people compared to other problems people have with crates.io, but I'd be fine with this.

Thank you for putting in the work to narrowly define an incremental solution that doesn't increase the amount of manual work that the crates.io team will need to do on an ongoing basis!

kornel: kornel: The reserved name won't appear in search results until cargo publish makes it a real permanent crate.

makes it a real permanent crate. Optionally: opening a crate page of a reserved name directly could display "reserved by $user", so the current convention of "contact me if you want this name" is preserved.

Today, if I want to check if a crate name is available, I search for the name I want. If I'm reading this correctly, with this change, I could do a search for a crate name, not get any results, and then I'd go to use the crate name and get an error message on publish that the crate name isn't available because it's been reserved (and does that error message say who has reserved it?)

So I think this proposal could use some more detail around how someone would go about finding out if a crate name is taken, reserved, or available, and some more detail about what the error messages will say.