Problem

Sometimes a cargo publish run of multiple packages will fail. It is then necessary to restart it.

It would be nice if we could run the whole publication from the top, and simply skip crates that were already published. There are probably other uses.

Proposed Solution

cargo publish --idempotent

If the current version of the crate has already been published, skips the crate and exits with a success status.

(Ideally it would download the crate and check it's identical to what is proposed to publish now, but I think that crates.io does unpredictable-to-cargo mangling of the uploaded data which makes such a check infeasible.)

Notes

No response