1 files changed, 18 insertions, 14 deletions
diff --git a/lib/rubygems/specification.rb b/lib/rubygems/specification.rb
index d59f57c49f..4e1a3a3801 100644
--- a/lib/rubygems/specification.rb
+++ b/lib/rubygems/specification.rb
@@ -182,6 +182,7 @@ class Gem::Specification < Gem::BasicSpecification
     @@default_value[k].nil?
   end
 
+  @@stubs = nil
   @@stubs_by_name = {}
 
   # Sentinel object to represent "not found" stubs
@@ -800,10 +801,8 @@ class Gem::Specification < Gem::BasicSpecification
   def self.stubs
     @@stubs ||= begin
       pattern = "*.gemspec"
-      stubs = installed_stubs(dirs, pattern) + default_stubs(pattern)
-      stubs = stubs.uniq {|stub| stub.full_name }
+      stubs = stubs_for_pattern(pattern, false)
 
-      _resort!(stubs)
       @@stubs_by_name = stubs.select {|s| Gem::Platform.match_spec? s }.group_by(&:name)
       stubs
     end
@@ -820,26 +819,31 @@ class Gem::Specification < Gem::BasicSpecification
     end
   end
 
-  EMPTY = [].freeze # :nodoc:
-
   ##
   # Returns a Gem::StubSpecification for installed gem named +name+
   # only returns stubs that match Gem.platforms
 
   def self.stubs_for(name)
-    if @@stubs_by_name[name]
-      @@stubs_by_name[name]
+    if @@stubs
+      @@stubs_by_name[name] || []
     else
-      pattern = "#{name}-*.gemspec"
-      stubs = installed_stubs(dirs, pattern).select {|s| Gem::Platform.match_spec? s } + default_stubs(pattern)
-      stubs = stubs.uniq {|stub| stub.full_name }.group_by(&:name)
-      stubs.each_value {|v| _resort!(v) }
-
-      @@stubs_by_name.merge! stubs
-      @@stubs_by_name[name] ||= EMPTY
+      @@stubs_by_name[name] ||= stubs_for_pattern("#{name}-*.gemspec")
     end
   end
 
+  ##
+  # Finds stub specifications matching a pattern from the standard locations,
+  # optionally filtering out specs not matching the current platform
+  #
+  def self.stubs_for_pattern(pattern, match_platform = true) # :nodoc:
+    installed_stubs = installed_stubs(Gem::Specification.dirs, pattern)
+    installed_stubs.select! {|s| Gem::Platform.match_spec? s } if match_platform
+    stubs = installed_stubs + default_stubs(pattern)
+    stubs = stubs.uniq {|stub| stub.full_name }
+    _resort!(stubs)
+    stubs
+  end
+
   def self._resort!(specs) # :nodoc:
     specs.sort! do |a, b|
       names = a.name <=> b.name