Proposal: add cargo to rust formula

[RSully]

I'm not sure if homebrew would prefer this as a separate formula or --with-cargo as an option within the rust formula.

For comparison:

• homebrew-php separates composer into its own formula
• node installs npm by default

My vote goes to installing cargo by default within the rust formula.

[DomT4]

I'd be 👍 on this but at last check Cargo wasn't stable yet? Or at least doesn't have a stable release?

Having to clone the git and then build Cargo from source manually is a bit of an additional pain, especially when we could be cloning slightly different Cargo sources into Rust on a day to day basis. Cargo also has 4 major dependencies that Rust doesn't.

The upside of npm inside Node is that it has stable releases, and doesn't force any additional dependencies. (Largely because Node ships those dependencies, which isn't trouble-free either, but eh).

[RSully]

That's a good point I overlooked: there aren't even any 0.x releases of Cargo from what I can see 😦.

Maybe I should close this until they start tagging versions?

[DomT4]

I'd await feedback from one of the maintainers to be sure, but my gut feeling is that Homebrew won't be able to support Cargo until they start tagging releases that both work every time and don't make any sudden, unexpected changes outside of that release schedule.

[diimdeep]

Last time I checked Cargo can't be compiled with current Rust version, that's why It is recommended to use Cargo with nightly Rust

[RSully]

Alright then, we should revisit this once a release of Cargo is tagged.

[DomT4]

SGTM 👍

[kron4eg]

Now when rust 1.0.0 beta came out, it's time to review this issue

[DomT4]

Are Cargo tagging usable releases yet?

[kron4eg]

@DomT4 nope :(

[DomT4]

I guess that's the primary problem. We'd probably need tagged releases that won't break against Rust stable.

[lloeki]

Seems like somehow cargo has a peculiar versioning scheme:

At the moment there aren't concrete plans to make releases of Cargo. The Cargo nightly that corresponds to releases of Rust is in this file: https://github.com/rust-lang/rust-packaging/blob/master/cargo-revs.txt. Note that it's only set up to permanently record cargo revisions for stable releases of Rust.

That is, a cargo release is whatever gets packaged within a rust release. Currently (rust 1.0.0-beta) this is (look for the SHA1):

$ ./cargo --version
cargo 0.0.1-pre-nightly (84d6d2c 2015-03-31) (built 2015-03-31)

[lloeki]

We'd probably need tagged releases that won't break against Rust stable.

There are two distinct situations one may have to consider:

1. building cargo against homebrew's rust
2. running cargo against homebrew's rust

Which one are we talking about here? Since cargo needs to fetch a cargo snapshot to build itself, it may not be that far of a stretch to allow the build process to fetch a nightly rust (as done by .travis.install.deps.sh, which is part of the README-documented workflow), at least while this is not solved. If the cargo crew isn't keen for tagging releases, maybe will this be a candidate for homebrew-head-only?

FWIW here's what I came up with, which builds the only cargo tag release (0.0.1-pre), as well as HEAD:

class Cargo < Formula
  homepage "https://crates.io"
  head "https://github.com/rust-lang/cargo", :using => :git
  version "0.0.1-pre"
  url "https://github.com/rust-lang/cargo/archive/v0.0.1-pre.tar.gz"
  sha256 "3c61260e8511fec344033a888f5dfcf3f0f13de86eecffd5903023082f475e5a"

  option "with-local-rust", "Build with Homebrew's rust"

  depends_on "cmake" => :build
  depends_on "python" => :build
  depends_on "pkg-config" => :build
  depends_on "curl" => :build unless build.with? "local-rust"
  depends_on "openssl"
  depends_on "rust"

  def install
    if build.head?
      system "git", "submodule", "update", "--init"
    end

    args = []
    if build.with? "local-rust"
      args << "--local-rust-root=#{Formula["rust"].opt_prefix}"
    else
      system "./.travis.install.deps.sh"
      args << "--local-rust-root=\"$PWD\"/rustc"
    end
    args << "--prefix=#{prefix}"
    system "./configure", *args
    system "make"
    system "make", "install"

    rm_rf prefix/"lib/rustlib/components"
    rm_rf prefix/"lib/rustlib/install.log"
    rm_rf prefix/"lib/rustlib/rust-installer-version"
    rm_rf prefix/"lib/rustlib/uninstall.sh"
  end

  test do
    system "#{bin}/cargo"
  end
end

[MikeMcQuaid]

Seems to me cargo should be part of the Rust formula.

[lloeki]

My thought exactly (way more inline with upstream), but a separate formula was best to get acquainted with the build sequence.

[MikeMcQuaid]

My thought exactly (way more inline with upstream), but a separate formula was best to get acquainted with the build sequence.

👍 Would you be able to submit a pull request? I can't promise we'll be able to merge it immediately but it definitely seems like something we'll want.

[lloeki]

Will do.

[lloeki]

Rust formula including cargo is theoretically ready: waiting for rust build to complete, which takes approximately ages and a half.

[lloeki]

==> Summary
/usr/local/Cellar/rust/1.0.0-beta: 5628 files, 291M, built in 81.0 minutes

Off we go onto the aforementioned Pull Request.