The filename without the .toml extension has been deprecated for years, and recent cargo now prints a lot of warnings when the deprecated file name is present.
.toml
Writing to the new file name should work in all environments we care about, so I think %cargo_prep can just write to the non-deprecated location unconditionally.
%cargo_prep
This has been implemented in https://pagure.io/fedora-rust/rust-packaging/c/146c0bec7738d7e3302f61391e3ea62522053446?branch=main and released as part of v26.3.
Metadata Update from @decathorpe: - Issue status updated to: Closed (was: Open)