Added post install hook to gemspec

lib/rubygems/specification.rb

@@ -135,6 +135,7 @@ class Gem::Specification
     :metadata                  => {},
     :name                      => nil,
     :platform                  => Gem::Platform::RUBY,
+    :post_install              => nil,
     :post_install_message      => nil,
     :rdoc_options              => [],
     :require_paths             => ['lib'],
@@ -374,6 +375,19 @@ def files
 
   attr_accessor :metadata
 
+  ##
+  # A block that gets called after the gem is installed.
+  #
+  # Usage:
+  #   spec.post_install do
+  #     # something amazing...
+  #   end
+
+  def post_install(&block)
+    return unless block_given?
+    Gem.post_install_hooks << block
+  end
+
   ##
   # Adds a development dependency named +gem+ with +requirements+ to this
   # gem.
@@ -1937,6 +1951,7 @@ def ruby_code(obj)
     when Time              then obj.strftime('%Y-%m-%d').dump
     when Numeric           then obj.inspect
     when true, false, nil  then obj.inspect
+    when Proc              then obj.inspect
     when Gem::Platform     then "Gem::Platform.new(#{obj.to_a.inspect})"
     when Gem::Requirement  then "Gem::Requirement.new(#{obj.to_s.inspect})"
     else raise Gem::Exception, "ruby_code case not handled: #{obj.class}"

test/rubygems/test_gem_installer.rb

@@ -957,6 +957,34 @@ def test_install_with_message
     assert_match %r|I am a shiny gem!|, @ui.output
   end
 
+  def test_install_with_successful_post_install
+    @spec.post_install do
+      @ui.say "Running post install hook!"
+    end
+
+    use_ui @ui do
+      path = Gem::Builder.new(@spec).build
+
+      @installer = Gem::Installer.new path
+      @installer.install
+    end
+
+    assert_match %r|Running post install hook!|, @ui.output
+  end
+
+  def test_install_with_failed_post_install
+    @spec.post_install do
+      raise Exception
+    end
+
+    assert_raises Exception do
+      path = Gem::Builder.new(@spec).build
+
+      @installer = Gem::Installer.new path
+      @installer.install
+    end
+  end
+
   def test_install_wrong_ruby_version
     use_ui @ui do
       installer = Gem::Installer.new old_ruby_required

test/rubygems/test_gem_specification.rb

@@ -82,6 +82,7 @@ def test_self_attribute_names
       metadata
       name
       platform
+      post_install
       post_install_message
       rdoc_options
       require_paths