add command 'cask outdated'

[axiac]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew tests with your changes locally?

---

Disclaimer for the unchecked item

A couple of weeks ago I was missing the brew cask outdated command. I checked the Issues and PRs on the Homebrew/brew repo and I couldn't find anything related so I decided to give it a try.
When I was ready to make a pull request I discovered PR #2250 was already created two days before and I learned about issue Homebrew/homebrew-cask#29301. I went back to coding, implemented the --greedy option too and now I have a complete PR for the cask outdated feature.

How it works:

When the --greedy options is not present in the command line, a Cask that has auto_updates true or version 'latest' is ignored, as required.

When --greedy is present, the value of auto_updates is ignored and the Cask is processed as explained below; the casks that have version 'latest' are always displayed as outdated.

The version of the Cask from tap is compared against the currently installed version of the application (versions.last). The Cask is outdated if the currently installed version is different than the version from the tap. In this case, all the local versions of the application are compared to the tap version and all that are different are reported as "outdated".

If the current installed version is the same as the tap version, the Cask is not reported as outdated, even if there are other (different) local versions.

Output formatting

The format of the command is the same as the output of brew outdated, including the processing of --verbose and --quiet command line options.

Other points of interest

The new functionality is accompanied by tests. The documentation (the man page) was updated.

[vitorgalvao]

It does happen occasionally.

[vitorgalvao]

The Cask is outdated if the currently installed version is smaller than the version from the tap.

You can’t compare “size”, because versions are non-standard, for us. A version can just as well be a number or an intelligible string. The only comparison that can be made is “is it different?”.

[ilovezfs]

I think sortable versions might also be a prerequisite for this making any sense.

[axiac]

You both are right regarding the version comparison. I had semantic versioning in mind but I overlooked that, as strings, "10" is smaller than "9". And semantic versioning is a foolish assumption in this case, anyway.

Simplified the version comparison in a new commit.

[reitermarkus]

ARGV.verbose? -> verbose?

[axiac]

Are you sure? It says: Error: undefined method `verbose?' for Hbc::CLI::Outdated:Class

[reitermarkus]

Ah, then it's CLI.verbose?, I thought it would use the CLI namespace.

[reitermarkus]

Use #select here.

[axiac]

#select is the function I was looking for (but it seems I was too lazy to read the complete list of Array methods and I concluded too early). Thank you!

[reitermarkus]

Let's not cache this. At the moment we are only using it only once anyways, but even if we were to use it multiple times, something will probably have changed between these calls.

[axiac]

#outdated? and outdated_versions are both called when --verbose. This is why the information is cached (versions is expensive).

Is it ok to (drop caching and the #outdated_versions method and) let #outdated? return a boolean and the list of outdated versions?

[reitermarkus]

Use != here instead of <.

[axiac]

This is the output format used by brew outdated and it is also the one suggested in Homebrew/homebrew-cask#29301

[reitermarkus]

See the discussion here: #2250 (comment)

[axiac]

I understood the reasons about using != to compare the versions and I changed the code.

Please remark the puts in front of that line. It is not a version comparison, "<" is part of the text that is displayed to the user:

$ brew cask outdated
cyberduck (5.3.7.23440, 5.3.8.23611) < 5.3.9.23624
virtualbox (5.1.14-112924) < 5.1.16-113841
virtualbox-extension-pack (5.1.14-112924) < 5.1.16-113841

[reitermarkus]

Yes, that is exactly the reason. Displaying < when we are only comparing with != doesn't make sense.

[axiac]

I got your point now. But I still wonder what kind of magic allows brew outdated compare the Formula versions using <.

[reitermarkus]

This is because Formulae use the comparable PkgVersion class, and Hbc::DSL::Version is a subclass of String, so it only performs a String comparison.

[reitermarkus]

Make this if version == current.

[reitermarkus]

This should be:

      if greedy
        return versions if version.latest?
      else
        return [] if auto_updates
      end

Otherwise, when I have the :latest version installed, but there is an updated cask with version 1.0.0, it will not show up as outdated.

[reitermarkus]

This must be removed after changing the above to if greedy.

[reitermarkus]

Remove this comment.

[reitermarkus]

Remove this comment.

[reitermarkus]

No need for the if here, version != v is enough.

[reitermarkus]

Or even select(&version.method(:!=)).

[reitermarkus]

Ok, I changed my mind, I think select { |v| version != v } is clearer.

[axiac]

It is clearer, indeed.

[reitermarkus]

Make this expect(c).to be_outdated everywhere.

[axiac]

It's expect(c).to_not be_outdated. Got it.

[reitermarkus]

Right, but use .not_to instead of .to_not.

[reitermarkus]

Instead of this, use allow(Hbc::CLI).to receive(:verbose?).and_return(true).

[axiac]

This eliminates the need to reset CLI.verbose in after, isn't it?

[reitermarkus]

Exactly.

[reitermarkus]

Define these like

let(:basic_cask) { Hbc::CaskLoader.load_from_file(TEST_FIXTURE_DIR/"cask/Casks/basic-cask.rb") }

above the before block.

[reitermarkus]

I think these are automatically removed after each test.

[joshka]

Heya, I'm disappointed that we ended up duplicating effort, but this looks much neater than my PR (#2250). I also learnt a bunch of ruby and rspec reading your version. Thanks :)

[reitermarkus]

No need to test this, since this is basically the same for every command and I think this is already tested elsewhere.

[axiac]

@reitermarkus you want to spoil my perfect code coverage ;-)
I agree it is not needed; I just exercised the things you taught me in your previous review (.not_to, mocking method calls) and I enjoyed using them. I removed the test now and rebased the branch.

[reitermarkus]

@reitermarkus you want to spoil my perfect code coverage ;-)

Fixed that for you, by adding a test for the help methods. 😄

[axiac]

@joshka Thank you for your appreciation. I'm sorry my PR rendered your work useless, it was not my intention. You can still implement cask upgrade (the second part of issue Homebrew/homebrew-cask#29301), I promise I won't do it. I don't feel the need for it; cask reinstall does (almost) the same thing for outdated casks.

[reitermarkus]

Thanks @axiac and @joshka for working on this!