1 files changed, 16 insertions, 2 deletions
diff --git a/tool/rbinstall.rb b/tool/rbinstall.rb
index 9d10f59a5d..5162498ecd 100755
--- a/tool/rbinstall.rb
+++ b/tool/rbinstall.rb
@@ -18,10 +18,17 @@ require 'shellwords'
 require 'optparse'
 require 'optparse/shellwords'
 require 'ostruct'
+require_relative 'vcs'
 
 STDOUT.sync = true
 File.umask(0)
 
+begin
+  $vcs = VCS.detect(File.expand_path('../..', __FILE__))
+rescue VCS::NotFoundError
+  $vcs = nil
+end
+
 def parse_args(argv = ARGV)
   $mantype = 'doc'
   $destdir = nil
@@ -555,13 +562,20 @@ module Gem
       super
       yield(self) if defined?(yield)
       self.executables ||= []
-      self.date ||= RUBY_RELEASE_DATE
     end
 
     def self.load(path)
       src = File.open(path, "rb") {|f| f.read}
       src.sub!(/\A#.*/, '')
-      eval(src, nil, path)
+      spec = eval(src, nil, path)
+      spec.date ||= last_date(path) || RUBY_RELEASE_DATE
+      spec
+    end
+
+    def self.last_date(path)
+      return unless $vcs
+      return unless time = $vcs.get_revisions(path)[2]
+      time.strftime("%Y-%m-%d")
     end
 
     def to_ruby