This has several advantages:
1. It takes up less space on disk in-between builds in the nix store.
2. It uses less space in the binary cache for vendor derivation packages.
3. It uses less network traffic downloading from the binary cache.
4. It plays nicely with hashed mirrors like tarballs.nixos.org, which only
substitute --flat hashes on single files (not recursive directory hashes).
5. It's consistent with how simple `fetchurl` src derivations work.
6. It provides a stronger abstraction between input src-package and output
package, e.g., it's harder to accidentally depend on the src derivation at
runtime by referencing something like `${src}/etc/index.html`. Likewise, in
the store it's harder to get confused with something that is just there as a
build-time dependency vs. a runtime dependency, since the build-time
src dependencies are tarred up.
Disadvantages are:
1. It takes slightly longer to untar at the start of a build.
As currently implemented, this attaches the compacted vendor.tar.gz feature as a
rider on `verifyCargoDeps`, since both of them are relatively newly implemented
behavior that change the `cargoSha256`.
If this PR is accepted, I will push forward the remaining rust packages with a
series of treewide PRs to update the `cargoSha256`s.
Also move the build-time dependencies to nativeBuildInputs, and drop perl as it no longer seems to be necessary (CMake is not looking for it any more).
A recent upgrade of cargo-vendor changed its output slightly, which
broke all cargoSha256 hashes in nixpkgs.
See https://github.com/NixOS/nixpkgs/issues/60668 for more information.
Since then, a few hashes have been fixed in master by hand, but there
were a lot still to do, so I did all of the ones left over with some
scripts I wrote.
The one hash I wasn’t able to update was habitat's, because it’s
currently broken and the build doesn’t get far enough to produce a
hash anyway.
`updateScript` lets us update packages automatically.
For packages that are hosted on the gnome mirror it's very easy to add
that. Inspired by https://github.com/NixOS/nixpkgs/issues/36150
I thought of filing a PR, but it would seem a useless step,
even though the release seems to bring lots of changes:
http://www.doxygen.nl/manual/changelog.html#log_1_8_15
My relatively simple use case still works (atop 18.09).
