cli/parser: rescue formula specification errors

[apainintheneck]

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Closes #16123

This came up recently where an outdated formula definition caused the program to crash with an ambiguous message when a user wanted to upgrade a cask instead. Catching these errors allows them to get handled later on improving error messages and defaults. Now if the only formula with the given name is invalid it will default to using the cask unless --formula is specified.

After changes:

$ brew install -n vagrant
Error: Failed to load formula: vagrant
formulae require at least a URL
Warning: Treating vagrant as a cask.
==> Would install 1 cask:
vagrant
$ brew install -n vagrant --formula
Error: formulae require at least a URL
Warning: Removed Sorbet lines from backtrace!
Rerun with --verbose to see the original backtrace
/usr/local/Homebrew/Library/Homebrew/formula.rb:306:in `determine_active_spec'
/usr/local/Homebrew/Library/Homebrew/formula.rb:237:in `initialize'
/usr/local/Homebrew/Library/Homebrew/formulary.rb:494:in `new'
/usr/local/Homebrew/Library/Homebrew/formulary.rb:494:in `get_formula'
/usr/local/Homebrew/Library/Homebrew/formulary.rb:771:in `factory'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:126:in `block in load_formula_or_cask'
/usr/local/Homebrew/Library/Homebrew/api.rb:197:in `with_no_api_env_if_needed'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:118:in `load_formula_or_cask'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:83:in `block in to_formulae_and_casks'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:81:in `each'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:81:in `flat_map'
/usr/local/Homebrew/Library/Homebrew/cli/named_args.rb:81:in `to_formulae_and_casks'
/usr/local/Homebrew/Library/Homebrew/cmd/install.rb:195:in `install'
/usr/local/Homebrew/Library/Homebrew/brew.rb:86:in `<main>'

[Bo98]

Eventually upstream will hopefully fix the formula specification, but then the user will get depends_on :linux issues so would still be nice to have better prioritisation for brew upgrade at some point.

[MikeMcQuaid]

Thanks again @apainintheneck!

[apainintheneck]

@Bo98 What do you mean by better prioritization? I guess we could try to resolve name conflicts by defaulting to the installed package if only one package with that name is installed for brew upgrade. Is that what you had in mind?

[Bo98]

Yeah. Feels more secure since it would prevent a tap from hijacking an existing install without the user really noticing sometimes.