1 files changed, 43 insertions, 8 deletions

diff --git a/lib/bundler/gem_helpers.rb b/lib/bundler/gem_helpers.rb
index 03c1f33fe2..6d926ce83f 100644
--- a/lib/bundler/gem_helpers.rb
+++ b/lib/bundler/gem_helpers.rb
@@ -31,16 +31,50 @@ module Bundler
 
     def platform_specificity_match(spec_platform, user_platform)
       spec_platform = Gem::Platform.new(spec_platform)
-      return [-1, -1, -1] if spec_platform == user_platform
-      return [5, 5, 5] if spec_platform.nil? || spec_platform == Gem::Platform::RUBY || user_platform == Gem::Platform::RUBY
+      return PlatformMatch::EXACT_MATCH if spec_platform == user_platform
+      return PlatformMatch::WORST_MATCH if spec_platform.nil? || spec_platform == Gem::Platform::RUBY || user_platform == Gem::Platform::RUBY
 
-      [
+      PlatformMatch.new(
+        PlatformMatch.os_match(spec_platform, user_platform),
+        PlatformMatch.cpu_match(spec_platform, user_platform),
+        PlatformMatch.platform_version_match(spec_platform, user_platform)
+      )
+    end
+    module_function :platform_specificity_match
+
+    def select_best_platform_match(specs, platform)
+      specs.select {|spec| spec.match_platform(platform) }.
+        min_by {|spec| platform_specificity_match(spec.platform, platform) }
+    end
+    module_function :select_best_platform_match
+
+    PlatformMatch = Struct.new(:os_match, :cpu_match, :platform_version_match)
+    class PlatformMatch
+      def <=>(other)
+        return nil unless other.is_a?(PlatformMatch)
+
+        m = os_match <=> other.os_match
+        return m unless m.zero?
+
+        m = cpu_match <=> other.cpu_match
+        return m unless m.zero?
+
+        m = platform_version_match <=> other.platform_version_match
+        m
+      end
+
+      EXACT_MATCH = new(-1, -1, -1).freeze
+      WORST_MATCH = new(1_000_000, 1_000_000, 1_000_000).freeze
+
+      def self.os_match(spec_platform, user_platform)
         if spec_platform.os == user_platform.os
           0
         else
           1
-        end,
+        end
+      end
 
+      def self.cpu_match(spec_platform, user_platform)
         if spec_platform.cpu == user_platform.cpu
           0
         elsif spec_platform.cpu == "arm" && user_platform.cpu.to_s.start_with?("arm")
@@ -49,17 +83,18 @@ module Bundler
           1
         else
           2
-        end,
+        end
+      end
 
+      def self.platform_version_match(spec_platform, user_platform)
         if spec_platform.version == user_platform.version
           0
         elsif spec_platform.version.nil?
           1
         else
           2
-        end,
-      ]
+        end
+      end
     end
-    module_function :platform_specificity_match
   end
 end