brew/Library/Homebrew/requirements/language_module_requirement.rb
Dominyk Tiller c5520d0050 languages: flag missing dependency requirement (#194)
This is in part designed to handle situations described in https://github.com/Homebrew/legacy-homebrew/issues/42273
where we tell someone to install a special dependency, but because we (rightly, IMO)
resolve special dependencies first users can end up being told to execute a command
on a tool that isn't yet installed and isn't immediately obvious how to install it.

In the situation raised there, with the `sile` formula people are being told to
`luarocks install xyz` but we hadn't installed Lua for them first, so they just
get a `command not found: luarocks` message. Perhaps it should be obvious enough
how to install said tools by looking at the formula's dependencies,
but it's not a huge burden on us to make life easier than that.

Shuffled over from https://github.com/Homebrew/legacy-homebrew/pull/42576.
2016-05-07 20:58:20 +01:00

55 lines
1.5 KiB
Ruby

require "requirement"
class LanguageModuleRequirement < Requirement
fatal true
def initialize(language, module_name, import_name = nil)
@language = language
@module_name = module_name
@import_name = import_name || module_name
super([language, module_name, import_name])
end
satisfy(:build_env => false) { quiet_system(*the_test) }
def message
s = <<-EOS.undent
Unsatisfied dependency: #{@module_name}
Homebrew does not provide special #{@language.to_s.capitalize} dependencies; install with:
`#{command_line} #{@module_name}`
EOS
unless [:python, :perl, :ruby].include? @language
s += <<-EOS.undent
You may need to: `brew install #{@language}`
EOS
end
s
end
def the_test
case @language
when :lua then %W[/usr/bin/env luarocks-5.2 show #{@import_name}]
when :lua51 then %W[/usr/bin/env luarocks-5.1 show #{@import_name}]
when :perl then %W[/usr/bin/env perl -e use\ #{@import_name}]
when :python then %W[/usr/bin/env python -c import\ #{@import_name}]
when :python3 then %W[/usr/bin/env python3 -c import\ #{@import_name}]
when :ruby then %W[/usr/bin/env ruby -rubygems -e require\ '#{@import_name}']
end
end
def command_line
case @language
when :lua then "luarocks-5.2 install"
when :lua51 then "luarocks-5.1 install"
when :perl then "cpan -i"
when :python then "pip install"
when :python3 then "pip3 install"
when :ruby then "gem install"
end
end
end