fixing incompatibilities with AR

6 files changed, 50 insertions, 14 deletions

diff --git a/lib/arel/algebra/predicates.rb b/lib/arel/algebra/predicates.rb
index 1b9667ac13..b761eab417 100644
--- a/lib/arel/algebra/predicates.rb
+++ b/lib/arel/algebra/predicates.rb
@@ -1,6 +1,6 @@
 module Arel
   module Predicates
-    class Predicate < Struct.new(:children)
+    class Predicate
       def or(other_predicate)
         Or.new(self, other_predicate)
       end
@@ -16,17 +16,13 @@ module Arel
       def not
         self.complement
       end
-
-      def == other
-        super || (self.class === other && children == other.children)
-      end
     end
 
     class Polyadic < Predicate
-      alias :predicates :children
+      attr_reader :predicates
 
       def initialize(*predicates)
-        super(predicates)
+        @predicates = predicates
       end
 
       # Build a Polyadic predicate based on:
@@ -42,6 +38,10 @@ module Arel
         )
       end
 
+      def ==(other)
+        super || predicates == other.predicates
+      end
+
       def bind(relation)
         self.class.new(
           *predicates.map {|p| p.find_correlate_in(relation)}
@@ -62,11 +62,19 @@ module Arel
     end
 
     class Unary < Predicate
-      alias :operand :children
+      attr_reader :operand
+
+      def initialize operand
+        @operand = operand
+      end
 
       def bind(relation)
         self.class.new(operand.find_correlate_in(relation))
       end
+
+      def == other
+        super || self.class === other && operand == other.operand
+      end
     end
 
     class Not < Unary
@@ -75,9 +83,9 @@ module Arel
       end
     end
 
-    class Binary < Predicate
-      alias :operand1 :children
+    class Binary < Unary
       attr_reader :operand2
+      alias :operand1 :operand
 
       def initialize left, right
         super(left)
diff --git a/lib/arel/engines/memory/predicates.rb b/lib/arel/engines/memory/predicates.rb
index e36afa38c2..1527b04056 100644
--- a/lib/arel/engines/memory/predicates.rb
+++ b/lib/arel/engines/memory/predicates.rb
@@ -1,6 +1,6 @@
 module Arel
   module Predicates
-    class Binary < Predicate
+    class Binary < Unary
       def eval(row)
         operand1.eval(row).send(operator, operand2.eval(row))
       end
diff --git a/lib/arel/engines/sql/engine.rb b/lib/arel/engines/sql/engine.rb
index 07940c6ef1..a314a972c0 100644
--- a/lib/arel/engines/sql/engine.rb
+++ b/lib/arel/engines/sql/engine.rb
@@ -4,11 +4,10 @@ module Arel
 
       def initialize(ar = nil)
         @ar = ar
-        @connection = nil
       end
 
       def connection
-        @connection ||= @ar && @ar.connection
+        @ar ? @ar.connection : nil
       end
 
       def adapter_name
diff --git a/lib/arel/engines/sql/predicates.rb b/lib/arel/engines/sql/predicates.rb
index 21d8f840c9..74a36d77c9 100644
--- a/lib/arel/engines/sql/predicates.rb
+++ b/lib/arel/engines/sql/predicates.rb
@@ -1,6 +1,6 @@
 module Arel
   module Predicates
-    class Binary < Predicate
+    class Binary < Unary
       def to_sql(formatter = nil)
         "#{operand1.to_sql} #{predicate_sql} #{operand1.format(operand2)}"
       end
diff --git a/lib/arel/session.rb b/lib/arel/session.rb
index 07809e53ba..f6016431c3 100644
--- a/lib/arel/session.rb
+++ b/lib/arel/session.rb
@@ -1,5 +1,7 @@
 module Arel
   class Session
+    @instance = nil
+
     def self.instance
       @instance || new
     end
diff --git a/spec/engines/sql/unit/engine_spec.rb b/spec/engines/sql/unit/engine_spec.rb
index f782f56938..85a9dc5bfb 100644
--- a/spec/engines/sql/unit/engine_spec.rb
+++ b/spec/engines/sql/unit/engine_spec.rb
@@ -1,12 +1,39 @@
 require 'spec_helper'
 
 module Arel
+  FakeAR = Struct.new(:connection)
+  class FakeConnection < Struct.new :called
+    def initialize c = []; super; end
+
+    def method_missing name, *args, &block
+      called << [name, args, block]
+    end
+  end
+
   describe Sql::Engine do
     before do
       @users = Table.new(:users)
       @users.delete
     end
 
+    describe "method missing" do
+      it "should pass through" do
+        conn = FakeConnection.new
+        engine = Arel::Sql::Engine.new FakeAR.new conn
+        engine.foo
+        conn.called.should == [[:foo, [], nil]]
+      end
+
+      it "should ask for a connection" do
+        conn   = FakeConnection.new
+        ar     = FakeAR.new conn
+        engine = Arel::Sql::Engine.new ar
+
+        ar.connection = nil
+        lambda { engine.foo }.should raise_error
+      end
+    end
+
     describe "CRUD" do
       describe "#create" do
         it "inserts into the relation" do