What's the new recommended syntax for OS conditional?

[huahaiy]

I had this in my formula:

class Datalevin < Formula
  desc "Simple, fast and durable Datalog database"
  homepage "https://github.com/juji-io/datalevin"
  version "0.5.3"
  license "EPL-1.0"

  if OS.linux?
    url "https://github.com/juji-io/datalevin/releases/download/0.5.3/dtlv-0.5.3-ubuntu-latest-amd64.zip"
    sha256 "e44b501028834d12e59daf3c6a374cfd39be20460a12e72a3d58e313c82e7c8c"
  else
    url "https://github.com/juji-io/datalevin/releases/download/0.5.3/dtlv-0.5.3-macos-latest-amd64.zip"
    sha256 "ef12240fbe429ec6a5a10728121d789d10e2a82f575d0c7867c44db6ea5f5875"
  end

  bottle :unneeded

  def install
    bin.install "dtlv"
  end
end

It worked. Until today. then github action test-bot produces this error:

==> Running TapSyntax#run!
==> brew readall --aliases huahaiy/brew
==> brew style huahaiy/brew
==> FAILED
Formula/datalevin.rb:7:6: C: [Correctable] Don't use 'if OS.linux?', use 'on_linux do' instead.
  if OS.linux?
     ^^^^^^^^^

1 file inspected, 1 offense detected, 1 offense auto-correctable
Error: Don't use 'if OS.linux?', use 'on_linux do' instead.

==> brew audit --tap=huahaiy/brew --except=version
Error: 1 failed step!
brew style huahaiy/brew
Error: Process completed with exit code 1.

What's the new syntax for my case? Thanks.

[carlocab]

brew says this is [Correctable], so you can leave it to brew to work out the correct syntax with brew style --fix datalevin.

[Bo98]

To add why: the usefulness is that on_linux do etc allows one to "simulate" another OS for information collection purposes (e.g. brew info or brew audit). This isn't used much right now but may be more in the future.

This does not matter inside install blocks etc as brew will never attempt an install for another OS, so the if OS.linux? conditional is still the way to go there. brew style recognises that and adjusts its recommendations accordingly.

[huahaiy]

@Bo98 @carlocab Fixed the style, now I got another error:

  brew test-bot --only-tap-syntax
  shell: /usr/bin/bash -e {0}
==> Using Homebrew/homebrew-test-bot 239af84 (Merge pull request #660 from carlocab/git)
==> Using Homebrew/brew 3.2.11-103-gbf95782ee (Merge pull request #12019 from valrus/services-plist-add-process-type)
==> Using Homebrew/linuxbrew-core a55e1a81ac4 (wangle: update 2021.09.06.00 bottle.)
==> Testing huahaiy/homebrew-brew 26a8f99 (update):

==> Running TapSyntax#run!
==> brew readall --aliases huahaiy/brew
==> brew style huahaiy/brew
==> FAILED
Formula/datalevin.rb:10:5: C: on_macos cannot include url. Only depends_on, patch, resource, deprecate!, disable!, conflicts_with, keg_only, and ignore_missing_libraries are allowed.
    url "https://github.com/juji-io/datalevin/releases/download/0.5.8/dtlv-0.5.8-macos-latest-amd64.zip"
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Formula/datalevin.rb:11:5: C: on_macos cannot include sha256. Only depends_on, patch, resource, deprecate!, disable!, conflicts_with, keg_only, and ignore_missing_libraries are allowed.
    sha256 "d051099a857083ec7a3fbfa11bf8262c0537d6d96acd12bcdadfecc21ef9b369"
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Formula/datalevin.rb:15:5: C: on_linux cannot include url. Only depends_on, patch, resource, deprecate!, disable!, conflicts_with, keg_only, and ignore_missing_libraries are allowed.
    url "https://github.com/juji-io/datalevin/releases/download/0.5.8/dtlv-0.5.8-ubuntu-latest-amd64.zip"
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Formula/datalevin.rb:16:5: C: on_linux cannot include sha256. Only depends_on, patch, resource, deprecate!, disable!, conflicts_with, keg_only, and ignore_missing_libraries are allowed.
    sha256 "aa966a9906acdc0e80768b5744f093978f44176fb3c4d55ff9e0b9cea58ef638"
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

1 file inspected, 4 offenses detected
Error: `on_macos` cannot include `url`. Only `depends_on`, `patch`, `resource`, `deprecate!`, `disable!`, `conflicts_with`, `keg_only`, and `ignore_missing_libraries` are allowed.
Error: `on_macos` cannot include `sha256`. Only `depends_on`, `patch`, `resource`, `deprecate!`, `disable!`, `conflicts_with`, `keg_only`, and `ignore_missing_libraries` are allowed.
Error: `on_linux` cannot include `url`. Only `depends_on`, `patch`, `resource`, `deprecate!`, `disable!`, `conflicts_with`, `keg_only`, and `ignore_missing_libraries` are allowed.
Error: `on_linux` cannot include `sha256`. Only `depends_on`, `patch`, `resource`, `deprecate!`, `disable!`, `conflicts_with`, `keg_only`, and `ignore_missing_libraries` are allowed.

==> brew audit --tap=huahaiy/brew --except=version
Error: 1 failed step!
brew style huahaiy/brew
Error: Process completed with exit code 1.

What do I do?

[Bo98]

Hmm, that is indeed a problem for taps that was perhaps overlooked. I'd file a bug report at https://github.com/Homebrew/brew.

[huahaiy]

For record, this is fixed in Homebrew/brew#12040