update Rakefile for correct build step (#360)

Author: jamis

Rakefile

@@ -53,8 +53,10 @@ RSpec::Core::RakeTask.new(:rspec)
 
 desc 'Build the bson gem'
 task :build => [ :clean_all, *(jruby? ? :compile : nil) ] do
-  output = "--output=#{ENV['GEM_FILE_NAME']}" if ENV['GEM_FILE_NAME']
-  system "gem build #{output} bson.gemspec"
+  command = [ 'gem', 'build' ]
+  command << "--output=#{ENV['GEM_FILE_NAME']}" if ENV['GEM_FILE_NAME']
+  command << ENV['GEMSPEC'] || 'bson.gemspec'
+  system(*command)
 end
 
 # `rake version` is used by the deployment system so get the release version
@@ -66,22 +68,10 @@ task :version do
   puts BSON::VERSION
 end
 
-# `rake gem_file_name` is used by the deployment system so get the name of
-# the gem file to be generated. It must do nothing more than just print the
-# name of the gem file to generate.
-desc 'Print the name of the gem file to generate.'
-task :gem_file_name do
-  require 'bson/version'
-  base = "bson-#{BSON::VERSION}"
-  base << '-java' if jruby?
-  puts "#{base}.gem"
-end
-
 task :clean_all => :clean do
-  FileUtils.rm_f(File.join(File.dirname(__FILE__), 'lib', "bson_native.bundle"))
-  FileUtils.rm_f(File.join(File.dirname(__FILE__), 'lib', "bson_native.so"))
-  FileUtils.rm_f(File.join(File.dirname(__FILE__), 'lib', "bson_native.o"))
-  FileUtils.rm_f(File.join(File.dirname(__FILE__), 'lib', "bson-ruby.jar"))
+  %w[ bson-ruby.jar bson_native.bundle bson_native.so bson_native.o ].each do |file|
+    FileUtils.rm_f(File.join(File.dirname(__FILE__), 'lib', file))
+  end
 end
 
 task :spec => :compile do
@@ -93,15 +83,6 @@ end
 # been built (and signed via GPG), so we just need `rake release` to
 # push the gem to rubygems.
 task :release do
-  require 'bson/version'
-
-  # confirm: there ought to be two gems, one for MRI, and one for Java. These
-  # will have been previously generated by the 'BSON Release' GitHub action.
-  gems = Dir['*.gem']
-  if gems.length != 2
-    abort "Expected two gem files to be ready to release; got #{gems.length}"
-  end
-
   if ENV['GITHUB_ACTION'].nil?
     abort <<~WARNING
       `rake release` must be invoked from the `BSON Release` GitHub action,
@@ -116,6 +97,13 @@ task :release do
     WARNING
   end
 
+  # confirm: there ought to be two gems, one for MRI, and one for Java. These
+  # will have been previously generated by the 'build' job.
+  gems = Dir['*.gem']
+  if gems.length != 2
+    abort "Expected two gem files to be ready to release; got #{gems.inspect}"
+  end
+
   gems.each do |gem|
     system 'gem', 'push', gem
   end