Gem::SpecFetcher#spec_for_dependency

# File tmp/rubies/ruby-3.0.5/lib/rubygems/spec_fetcher.rb, line 152
def spec_for_dependency(dependency, matching_platform=true)
  tuples, errors = search_for_dependency(dependency, matching_platform)

  specs = []
  tuples.each do |tup, source|
    begin
      spec = source.fetch_spec(tup)
    rescue Gem::RemoteFetcher::FetchError => e
      errors << Gem::SourceFetchProblem.new(source, e)
    else
      specs << [spec, source]
    end
  end

  return [specs, errors]
end