[Definition] Only sort platforms once in expand_dependencies

lib/bundler/definition.rb

@@ -890,11 +890,12 @@ def concat_ruby_version_requirements(ruby_version, ruby_versions = [])
     end
 
     def expand_dependencies(dependencies, remote = false)
+      sorted_platforms = Resolver.sort_platforms(@platforms)
       deps = []
       dependencies.each do |dep|
         dep = Dependency.new(dep, ">= 0") unless dep.respond_to?(:name)
         next if !remote && !dep.current_platform?
-        platforms = dep.gem_platforms(@platforms)
+        platforms = dep.gem_platforms(sorted_platforms)
         if platforms.empty?
           mapped_platforms = dep.platforms.map {|p| Dependency::PLATFORM_MAP[p] }
           Bundler.ui.warn \
@@ -904,7 +905,7 @@ def expand_dependencies(dependencies, remote = false)
             "To add those platforms to the bundle, " \
             "run `bundle lock --add-platform #{mapped_platforms.join " "}`."
         end
-        Resolver.sort_platforms(platforms).each do |p|
+        platforms.each do |p|
           deps << DepProxy.new(dep, p) if remote || p == generic_local_platform
         end
       end

lib/bundler/dependency.rb

@@ -90,16 +90,14 @@ def initialize(name, version, options = {}, &blk)
       @autorequire = Array(options["require"] || []) if options.key?("require")
     end
 
+    # Returns the platforms this dependency is valid for, in the same order as
+    # passed in the `valid_platforms` parameter
     def gem_platforms(valid_platforms)
       return valid_platforms if @platforms.empty?
 
-      platforms = []
-      @platforms.each do |p|
-        platform = PLATFORM_MAP[p]
-        next unless valid_platforms.include?(platform)
-        platforms |= [platform]
-      end
-      platforms
+      @gem_platforms ||= @platforms.map {|pl| PLATFORM_MAP[pl] }.compact.uniq
+
+      valid_platforms & @gem_platforms
     end
 
     def should_include?