Increase test coverage for subclasses_of. Closes #7335.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6036 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 45 insertions, 6 deletions

diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 2219d1fd7e..63cf492fe5 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Increase test coverage for subclasses_of. Closes #7335. [Roman2K, Nicholas Seckar]
+
 * Remove unused code from Duration#inspect.  Closes #7180.  [Rich Collins]
 
 * Added test coverage for Inflector.inflections.clear.  Closes #7179. [Rich Collins]
diff --git a/activesupport/lib/active_support/core_ext/object/extending.rb b/activesupport/lib/active_support/core_ext/object/extending.rb
index e15b4bf385..8a82f71c0f 100644
--- a/activesupport/lib/active_support/core_ext/object/extending.rb
+++ b/activesupport/lib/active_support/core_ext/object/extending.rb
@@ -6,11 +6,11 @@ class Object #:nodoc:
   def subclasses_of(*superclasses)
     subclasses = []
     ObjectSpace.each_object(Class) do |k|
-      next if # Exclude this class if
-        (k.ancestors & superclasses).empty? || # It's not a subclass of our supers
-        superclasses.include?(k) || # It *is* one of the supers
-        eval("! defined?(::#{k})") || # It's not defined.
-        eval("::#{k}").object_id != k.object_id
+      next unless # Exclude this class unless
+        superclasses.any? { |superclass| k < superclass } &&        # It *is* a subclass of our supers
+        eval("defined?(::#{k}) && ::#{k}.object_id == k.object_id") # It *is* defined
+          # Note that we check defined? in case we find a removed class that has
+          # yet to be garbage collected.
       subclasses << k
     end
     subclasses
diff --git a/activesupport/test/core_ext/object_and_class_ext_test.rb b/activesupport/test/core_ext/object_and_class_ext_test.rb
index e48d87a198..1fbb853bc9 100644
--- a/activesupport/test/core_ext/object_and_class_ext_test.rb
+++ b/activesupport/test/core_ext/object_and_class_ext_test.rb
@@ -11,6 +11,16 @@ class ClassJ < ClassI; end
 class ClassK
 end
 module Nested
+  class << self
+    def on_const_missing(&callback)
+      @on_const_missing = callback
+    end
+    private
+      def const_missing(mod_id)
+        @on_const_missing[mod_id] if @on_const_missing
+        super
+      end
+  end
   class ClassL < ClassK
   end
 end
@@ -41,9 +51,12 @@ class ClassExtTest < Test::Unit::TestCase
   end
 
   def test_subclasses_of
+    cj = ClassJ
     assert_equal [ClassJ], Object.subclasses_of(ClassI)
     ClassI.remove_subclasses
     assert_equal [], Object.subclasses_of(ClassI)
+  ensure
+    Object.const_set :ClassJ, cj
   end
 
   def test_subclasses_of_should_find_nested_classes
@@ -60,7 +73,31 @@ class ClassExtTest < Test::Unit::TestCase
     subclasses = Object.subclasses_of(ClassK)
     assert subclasses.include?(new_class)
     assert ! subclasses.include?(old_class)
-  end
+  ensure
+    Nested.const_set :ClassL, old_class unless defined?(Nested::ClassL)
+  end
+  
+  def test_subclasses_of_should_not_trigger_const_missing
+    const_missing = false
+    Nested.on_const_missing { const_missing = true }
+    
+    subclasses = Object.subclasses_of ClassK
+    assert !const_missing
+    assert_equal [ Nested::ClassL ], subclasses
+    
+    removed = Nested.send :remove_const, :ClassL   # keep it in memory
+    subclasses = Object.subclasses_of ClassK
+    assert !const_missing
+    assert subclasses.empty?
+  ensure
+    Nested.const_set :ClassL, removed unless defined?(Nested::ClassL)
+  end
+  
+  def test_subclasses_of_with_multiple_roots
+    classes = Object.subclasses_of(ClassI, ClassK)
+    assert_equal %w(ClassJ Nested::ClassL), classes.collect(&:to_s).sort
+  end
+  
 end
 
 class ObjectTests < Test::Unit::TestCase