Merge pull request #6972 from rubygems/segiddins/reduce-allocations-for-stub-specifications

(cherry picked from commit 84ea4e7)

Author: martinemde

lib/rubygems/basic_specification.rb

@@ -133,9 +133,9 @@ def full_gem_path
 
   def full_name
     if platform == Gem::Platform::RUBY || platform.nil?
-      "#{name}-#{version}".dup.tap(&Gem::UNTAINT)
+      (+"#{name}-#{version}").tap(&Gem::UNTAINT)
     else
-      "#{name}-#{version}-#{platform}".dup.tap(&Gem::UNTAINT)
+      (+"#{name}-#{version}-#{platform}").tap(&Gem::UNTAINT)
     end
   end
 

lib/rubygems/stub_specification.rb

@@ -35,7 +35,7 @@ class StubLine # :nodoc: all
 
     def initialize(data, extensions)
       parts          = data[PREFIX.length..-1].split(" ", 4)
-      @name          = parts[0].freeze
+      @name          = -parts[0]
       @version       = if Gem::Version.correct?(parts[1])
         Gem::Version.new(parts[1])
       else
@@ -113,14 +113,19 @@ def data
 
         Gem.open_file loaded_from, OPEN_MODE do |file|
           file.readline # discard encoding line
-          stubline = file.readline.chomp
+          stubline = file.readline
           if stubline.start_with?(PREFIX)
-            extensions = if /\A#{PREFIX}/ =~ file.readline.chomp
-              $'.split "\0"
-            else
-              StubLine::NO_EXTENSIONS
-            end
+            extline = file.readline
 
+            extensions =
+              if extline.delete_prefix!(PREFIX)
+                extline.chomp!
+                extline.split "\0"
+              else
+                StubLine::NO_EXTENSIONS
+              end
+
+            stubline.chomp! # readline(chomp: true) allocates 3x as much as .readline.chomp!
             @data = StubLine.new stubline, extensions
           end
         rescue EOFError