Add support for displaying versions in list command

[coder17934]

Adds a --versions switch to brew cask list that shows the
versions of installed Casks.

Uses the same flag as Homebrew does, see brew list --versions [formulae]

[rolandwalker]

Thanks! We would like to match Homebrew semantics whenever possible.

The only reason I haven't merged this yet is that I intend to update the man page.

[federicobond]

The one problem I see with this implementation is that it lists latest rather than installed versions, so it differs with its homebrew counterpart.

[rolandwalker]

Oh right, and we don't provide an interface to that information yet. This PR would match Homebrew's syntax, but not Homebrew's semantics.

It will be a number of weeks until we add the relevant functionality, but on the other hand it is merely weeks. Let's leave this PR open?

[coder17934]

@federicobond You are absolutely right, I was unsure of how to handle self-updating casks.

@rolandwalker Does that mean that Cask will be able to infer versions of self-updating casks? That would be awesome! Either way, I happy to leave this for now and revisit in a few weeks.

[alebcay]

@Anvar It's technically possible (and it wouldn't be a Cask-specific sort of thing). Versions are labeled in a rather clear and well-standardized format within Mac app bundles, unlike apps in Windows (.exe) and Linux (miscellaneous binary formats).

[rolandwalker]

@Anvar yes, although there are three different version numbers

• the version number in the Cask when you installed
• the version number in the latest Cask definition
• the version number in the app (which may have changed because of self-update)

We have been taking about reading version numbers from the app bundle since #260, but now it is the subject of active work, especially wrt self-updating apps: #3105, #4847, #4412, and many more.

We are also changing the spelling of the link stanza to app, in part to indicate that we will apply new semantics to an app stanza such as extracting the version number from Info.plist inside the bundle. (#4845, #4688).

It will be a while until all these changes come to fruition in the interface, but we are reorganizing the code and Casks to support these features.

[coder17934]

That sounds great, thanks for the update!

[vitorgalvao]

Future planned features would render this useless, so closing.