Solved a false positives problem, after creating specs which demonstr…

…ated it.

lib/array.rb

@@ -12,7 +12,9 @@ def stepwise
   end
   def comparing_collect
     accumulator = [] # collect implementation copied from Rubinius
-    stepwise {|element1, element2| accumulator << element1 if yield(element1, element2)}
+    stepwise do |element1, element2|
+      accumulator << element1 if yield(element1, element2)
+    end
     accumulator.compact
   end
 end

lib/node_analysis.rb

@@ -18,7 +18,8 @@ def homonyms
     end
     def diff(threshold)
       @method_definitions.comparing_collect do |method_definition_1, method_definition_2|
-        threshold >= (method_definition_1.body - method_definition_2.body).size
+        next if method_definition_1.flatten.size < method_definition_2.flatten.size
+        threshold >= (method_definition_1.body.flatten - method_definition_2.body.flatten).size
       end
     end
   end

spec/diff_false_positives/app/models/post.rb

@@ -0,0 +1,5 @@
+class Post < ActiveRecord::Base
+  def recent
+    find(:all)
+  end
+end

spec/diff_false_positives/app/models/user.rb

@@ -0,0 +1,9 @@
+class User < ActiveRecord::Base
+  def login(credentials)
+    find(:first, :conditions => ["name = ? and password = ?", credentials[:name], credentials[:password]])
+  end
+
+  def dropdown
+    find(:all).collect { |u| [u.name, u.name] }
+  end
+end

spec/model_spec.rb

@@ -152,4 +152,12 @@
     @model.parse("spec/two_node_diff")
     @model.method_definitions[0].filename.should == "spec/two_node_diff/second_file.rb"
   end
+  it "doesn't return false positives for one-node diffs" do
+    @model.parse("spec/diff_false_positives")
+    @model.diff(1).should == []
+  end
+  it "doesn't return false positives for five-node diffs" do
+    @model.parse("spec/diff_false_positives")
+    @model.diff(5).should == []
+  end
 end