this is as close as it's been

2 files changed, 35 insertions, 0 deletions

diff --git a/spec/arel/integration/joins/with_adjacency_spec.rb b/spec/arel/integration/joins/with_adjacency_spec.rb
index 4ffdf1f64f..ab63fecb46 100644
--- a/spec/arel/integration/joins/with_adjacency_spec.rb
+++ b/spec/arel/integration/joins/with_adjacency_spec.rb
@@ -107,6 +107,13 @@ module Arel
                   .on(@predicate)   \
               .should disambiguate_attributes(@relation1[:id], @relation2[:id])
             end
+            
+            it '' do
+              r0 = @relation1.select(@predicate)
+              r1 = r0.alias
+              r = r0.join(r1).on(@predicate)
+              r.should disambiguate_attributes(r0[:id], r1[:id])
+            end
           end
           
           describe 'when the right relation is extremely compound' do
diff --git a/spec/matchers/disambiguate_attributes.rb b/spec/matchers/disambiguate_attributes.rb
new file mode 100644
index 0000000000..bee7d22b0c
--- /dev/null
+++ b/spec/matchers/disambiguate_attributes.rb
@@ -0,0 +1,28 @@
+module DisambiguateAttributesMatcher
+  class DisambiguateAttributes
+    def initialize(attributes)
+      @attributes = attributes
+    end
+    
+    def matches?(actual)
+      @actual = actual
+      attribute1, attribute2 = @attributes
+      @actual[attribute1].descends_from?(attribute1) &&
+        !@actual[attribute1].descends_from?(attribute2) &&
+        @actual[attribute2].descends_from?(attribute2)
+    end
+    
+    def failure_message
+      ""
+      # "expected #{@actual} to disambiguate its attributes"
+    end
+    
+    def negative_failure_message
+      "expected #{@actual} to not disambiguate its attributes"
+    end
+  end
+  
+  def disambiguate_attributes(*attributes)
+    DisambiguateAttributes.new(attributes)
+  end
+end
\ No newline at end of file