Merge pull request #161 from Noemj/master

Mysql2 prepared statements bind substitution fix

lib/arel/visitors/bind_visitor.rb

@@ -12,13 +12,23 @@ def accept node, &block
       end
 
       private
+
+      def visit_Arel_Nodes_Assignment o
+        if o.right.is_a? Arel::Nodes::BindParam
+          "#{visit o.left} = #{visit o.right}"
+        else
+          super
+        end
+      end
+
       def visit_Arel_Nodes_BindParam o
         if @block
           @block.call
         else
           super
         end
       end
+
     end
   end
 end

test/visitors/test_bind_visitor.rb

@@ -1,9 +1,28 @@
 require 'helper'
 require 'arel/visitors/bind_visitor'
+require 'support/fake_record'
 
 module Arel
   module Visitors
-    class TestBindVisitor < MiniTest::Unit::TestCase
+    class TestBindVisitor < MiniTest::Unit::TestCase 
+
+      ##
+      # Tests visit_Arel_Nodes_Assignment correctly
+      # substitutes binds with values from block
+      def test_assignment_binds_are_substituted
+        table = Table.new(:users)
+        um = Arel::UpdateManager.new Table.engine
+        bp = Nodes::BindParam.new '?'
+        um.set [[table[:name], bp]]
+        visitor = Class.new(Arel::Visitors::ToSql) {
+          include Arel::Visitors::BindVisitor
+        }.new Table.engine.connection
+
+        assignment = um.ast.values[0]
+        actual = visitor.accept(assignment) { "replace" } 
+        actual.must_be_like "\"name\" = replace"
+      end
+
       def test_visitor_yields_on_binds
         visitor = Class.new(Arel::Visitors::Visitor) {
           def initialize omg