Gem::Specification#activate_dependencies

# File tmp/rubies/ruby-4.0.0/lib/rubygems/specification.rb, line 1391
def activate_dependencies
  unresolved = Gem::Specification.unresolved_deps

  runtime_dependencies.each do |spec_dep|
    if loaded = Gem.loaded_specs[spec_dep.name]
      next if spec_dep.matches_spec? loaded

      msg = "can't satisfy '#{spec_dep}', already activated '#{loaded.full_name}'"
      e = Gem::LoadError.new msg
      e.name = spec_dep.name

      raise e
    end

    specs = spec_dep.matching_specs(true).uniq(&:full_name)

    if specs.size == 0
      raise Gem::MissingSpecError.new(spec_dep.name, spec_dep.requirement, "at: #{spec_file}")
    elsif specs.size == 1
      specs.first.activate
    else
      name = spec_dep.name
      unresolved[name] = unresolved[name].merge spec_dep
    end
  end

  unresolved.delete self.name
end