Add the ability to 'add' `mas` dependencies to Brewfile

[boldandbrad]

Goal

Add the ability to add Brewfile lines of the following format: mas "name", id: 12345678

Assumptions

1. The "name" value itself does not matter to mas for install, only the "id" does (mas install [ID])
2. Recent versions of macOS prohibit mas from installing applications that have not been previously purchased/installed on a Mac by the active Apple ID - mas known issues

Potential Command Structures

• brew add --mas [PARAM(S)]

  • Syntax is consistent with brew add --cask/formula
  • Requires refactor of existing code to implement

• brew mas [PARAM(S)]

  • Not consistent with existing structure
  • Could require inconsistent implementation of eventual brew drop/brew mas drop
  • Does not require refactor of existing code to implement

Potential Params

• Only [ID]

  • Easy for user to obtain via mas list if it was previously installed (Assumption 2)
  • brew add runs mas info [ID] to get the app's "name" automatically

• Only [NAME]

  • Easy for user to obtain via mas list if it was previously installed (Assumption 2)
  • brew add runs mas search [NAME] to get the app's "id" automatically - might require parsing and user input if a direct match is not found

• Both [NAME:ID]

  • Easy for user to obtain both via mas list if it was previously installed (Assumption 2)
  • brew add does not need to invoke mas info or mas search
  • Could make it difficult to support adding multiple mas dependencies at once (if we want to support that)

Inspiration/Reference

• brew bundle dump implementation for mas dependencies: mac_app_store_dumper_spec.rb
• Initial discussion/context in #1

[superatomic]

Thank you so much for this detailed write-up! This is very helpful.

In addition, dumping mas apps is also implemented here: mac_app_store_dumper.rb I'm not quite sure what the spec file is (it might be test cases?) but I tend to find that the implementations normally are in the lib/ directory.

[superatomic]

I think all three ways of specifying mas applications can work with the brew add command in general alongside formulae and casks by using a bit of special syntax. Since the colon (:) doesn't appear in any formula names, it's a perfect character to indicate a mas app.

The form of a mas app would be ID:NAME, or /^\d+:[^:]+$/ as a regular expression. In addition, we could also accept different segments of the full syntax, like :NAME to search for the id by name, or ID: to let the name be automatically filled in. And because the only formula/cask that is just numbers is the cask 7777, the trailing colon at the end of the ID could be optional, with priority being for the formulae and casks first.

For example, this line would add the mas app with the ID 1482454543, the mas apps named xcode and bear, and the casks 7777 and firefox to the Brewfile:

brew add 1482454543 497799835:xcode :bear 7777 firefox

To add the mas app with an ID of 7777 instead of the cask, both brew add --mas 7777 and brew add 7777: would work.

---

Now, this is just one way of solving it. The advantage of using the colon separator this way is that it allows for there to be no confusion about what is meant to be a mas app, and to me, removing sections of the full ID:NAME format to have them be filled in feels natural. It also allows for typing brew add ID in all cases except for app 7777, which doesn't actually appear to be a valid app.

If you have any different ideas or improvements to this one, please let me know. Also, I swapped the order of the ID and NAME just because :firefox looked better than firefox: to me, and because it kind of makes sense for the most important bit of information (the id) to come first. Tell me if you preferred it the other way around.

[boldandbrad]

I like your suggested implementation for a few reasons:

• Supports adding multiple items to the Brewfile at once (and across all types)
• Consistent with the current structure
• Easy for the user as the tool handles multiple cases automatically if the user doesn't have all pieces of information available
• The order of ID:NAME actually makes more sense considering that's consistent with how mas list and mas search output

The only other things I'll note are...

• NAME should support being surrounded in quotes. Some app names in the App Store have spaces in them. Although the value doesn't matter for mas or brewfile, if people prefer the exact name, or copy it from mas output, they will need to wrap it in quotes so it doesn't get read as multiple formulae -> brew add :"Canary Mail"
• Although I don't personally use Whalebrew, we might want to check to make sure that our regex implementation wouldn't make it impossible or difficult to add whalebrew support later if others come along with that need. I can do some research on this if you like.

[boldandbrad]

After digging a little bit through the whalebrew repo, I don't think we need to worry about our regex. It seems like whalebrew formulae don't include : and almost all of them start with whalebrew/ which would be fairly easy to catch aside from potential conflict with the homebrew whalebrew formulae itself. Either way, it shouldn't be a concern for this issue.

[superatomic]

Regarding supporting names in quotes, I believe the shell itself can already handle that. By putting single quotes, double quotes, or escaping spaces, the name will be interpreted as one name once it is received by the argument parser.

For example, with current functionality, typing any of these:

brew add :"Canary Mail"
brew add :'Canary Mail'
brew add :Canary\ Mail
brew add :Canary' 'Mail
brew add ':Canary Mail'

Outputs the same exact error message:

Error: No available formula with the name ":canary mail".

Built-in commands like brew install also behave in the same way.