[rubygems/rubygems] Fix force_ruby_platform ignored when lockfile includes the current specific platform

https://github.com/rubygems/rubygems/commit/9ca371adf8

lib/bundler/definition.rb

@@ -496,6 +496,7 @@ module Bundler
 
     def current_ruby_platform_locked?
       return false unless generic_local_platform == Gem::Platform::RUBY
+      return false if Bundler.settings[:force_ruby_platform] && !@platforms.include?(Gem::Platform::RUBY)
 
       current_platform_locked?
     end

spec/bundler/runtime/platform_spec.rb

@@ -232,6 +232,20 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
     expect(the_bundle).to include_gems "nokogiri 1.4.2", "platform_specific 1.0 RUBY"
   end
 
+  it "allows specifying only-ruby-platform even if the lockfile is locked to a specific compatible platform" do
+    install_gemfile <<-G
+      source "#{file_uri_for(gem_repo1)}"
+      gem "nokogiri"
+      gem "platform_specific"
+    G
+
+    bundle "config set force_ruby_platform true"
+
+    bundle "install"
+
+    expect(the_bundle).to include_gems "nokogiri 1.4.2", "platform_specific 1.0 RUBY"
+  end
+
   it "doesn't pull platform specific gems on truffleruby", :truffleruby do
     install_gemfile <<-G
      source "#{file_uri_for(gem_repo1)}"