Generate lib/cucumber/messages_pb.rb on install

Author: vincent-psarga

cucumber-messages/ruby/Makefile

@@ -6,4 +6,4 @@ lib/cucumber/messages_pb.rb: messages.proto
 	protoc -I. -I/usr/local/include --ruby_out lib/cucumber $<
 
 clean:
-	rm -f lib/cucumber/messages_pb.rb
+	rm -f lib/cucumber/messages_pb.rb pkg/cucumber-messages-*.gem

cucumber-messages/ruby/cucumber-messages.gemspec

@@ -10,6 +10,7 @@ Gem::Specification.new do |s|
   s.platform    = Gem::Platform::RUBY
   s.license     = "MIT"
   s.required_ruby_version = ">= 2.3"
+  s.extensions = ["ext/cucumber-messages/extconf.rb".freeze]
 
   s.metadata    = {
                     'bug_tracker_uri'   => 'https://github.com/cucumber/cucumber/issues',
@@ -31,6 +32,7 @@ Gem::Specification.new do |s|
   s.files            = Dir[
     'README.md',
     'LICENSE',
+    'messages.proto',
     'lib/**/*'
   ]
   s.test_files       = Dir['spec/**/*']

cucumber-messages/ruby/ext/cucumber-messages/extconf.rb

@@ -0,0 +1,20 @@
+require "mkmf"
+
+find_executable('protoc')
+
+File.open(File.join(Dir.pwd, 'Makefile'), 'w') do |file|
+  file.write %Q(
+default:
+\tpushd ../.. && protoc -I. -I/usr/local/include --ruby_out lib/cucumber messages.proto && popd
+
+install:
+\t@echo "Not much to do in fact"
+.PHONY: clean
+
+clean:
+\trm ../../lib/cucumber/messages_pb.rb
+.PHONY: clean
+)
+end
+
+$makefile_created = true