Fix eager loading of associations causing table name collisions

[#4463 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/associations.rb

@@ -1737,6 +1737,14 @@ module ActiveRecord
             build(associations)
           end
 
+          def graft(*associations)
+            associations.each do |association|
+              join_associations.detect {|a| association == a} ||
+              build(association.reflection.name, association.find_parent_in(self), association.join_class)
+            end
+            self
+          end
+
           def join_associations
             @joins[1..-1].to_a
           end
@@ -1745,6 +1753,16 @@ module ActiveRecord
             @joins[0]
           end
 
+          def count_aliases_from_table_joins(name)
+            quoted_name = join_base.active_record.connection.quote_table_name(name.downcase)
+            join_sql = join_base.table_joins.to_s.downcase
+            join_sql.blank? ? 0 :
+              # Table names
+              join_sql.scan(/join(?:\s+\w+)?\s+#{quoted_name}\son/).size +
+              # Table aliases
+              join_sql.scan(/join(?:\s+\w+)?\s+\S+\s+#{quoted_name}\son/).size
+          end
+
           def instantiate(rows)
             rows.each_with_index do |row, i|
               primary_id = join_base.record_id(row)
@@ -1789,22 +1807,22 @@ module ActiveRecord
           end
 
           protected
-            def build(associations, parent = nil)
+            def build(associations, parent = nil, join_class = Arel::InnerJoin)
               parent ||= @joins.last
               case associations
                 when Symbol, String
                   reflection = parent.reflections[associations.to_s.intern] or
                   raise ConfigurationError, "Association named '#{ associations }' was not found; perhaps you misspelled it?"
                   @reflections << reflection
-                  @joins << build_join_association(reflection, parent)
+                  @joins << build_join_association(reflection, parent).with_join_class(join_class)
                 when Array
                   associations.each do |association|
-                    build(association, parent)
+                    build(association, parent, join_class)
                   end
                 when Hash
                   associations.keys.sort{|a,b|a.to_s<=>b.to_s}.each do |name|
-                    build(name, parent)
-                    build(associations[name])
+                    build(name, parent, join_class)
+                    build(associations[name], nil, join_class)
                   end
                 else
                   raise ConfigurationError, associations.inspect
@@ -1881,6 +1899,12 @@ module ActiveRecord
               @table_joins   = joins
             end
 
+            def ==(other)
+              other.is_a?(JoinBase) &&
+              other.active_record == active_record &&
+              other.table_joins == table_joins
+            end
+
             def aliased_prefix
               "t0"
             end
@@ -1946,6 +1970,27 @@ module ActiveRecord
               end
             end
 
+            def ==(other)
+              other.is_a?(JoinAssociation) &&
+              other.reflection == reflection &&
+              other.parent == parent
+            end
+
+            def find_parent_in(other_join_dependency)
+              other_join_dependency.joins.detect do |join|
+                self.parent == join
+              end
+            end
+
+            def join_class
+              @join_class ||= Arel::InnerJoin
+            end
+
+            def with_join_class(join_class)
+              @join_class = join_class
+              self
+            end
+
             def association_join
               return @join if @join
 
@@ -2045,27 +2090,25 @@ module ActiveRecord
             end
 
             def join_relation(joining_relation, join = nil)
-              if (relations = relation).is_a?(Array)
-                joining_relation.joins(Relation::JoinOperation.new(relations.first, Arel::OuterJoin, association_join.first)).
-                  joins(Relation::JoinOperation.new(relations.last, Arel::OuterJoin, association_join.last))
-              else
-                joining_relation.joins(Relation::JoinOperation.new(relations, Arel::OuterJoin, association_join))
-              end
+              joining_relation.joins(self.with_join_class(Arel::OuterJoin))
             end
 
             protected
 
               def aliased_table_name_for(name, suffix = nil)
-                if !parent.table_joins.blank? && parent.table_joins.to_s.downcase =~ %r{join(\s+\w+)?\s+#{active_record.connection.quote_table_name name.downcase}\son}
-                  @join_dependency.table_aliases[name] += 1
+                if @join_dependency.table_aliases[name].zero?
+                  @join_dependency.table_aliases[name] = @join_dependency.count_aliases_from_table_joins(name)
                 end
 
-                unless @join_dependency.table_aliases[name].zero?
-                  # if the table name has been used, then use an alias
+                if !@join_dependency.table_aliases[name].zero? # We need an alias
                   name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}"
-                  table_index = @join_dependency.table_aliases[name]
                   @join_dependency.table_aliases[name] += 1
-                  name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index+1}" if table_index > 0
+                  if @join_dependency.table_aliases[name] == 1 # First time we've seen this name
+                    # Also need to count the aliases from the table_aliases to avoid incorrect count
+                    @join_dependency.table_aliases[name] += @join_dependency.count_aliases_from_table_joins(name)
+                  end
+                  table_index = @join_dependency.table_aliases[name]
+                  name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index}" if table_index > 1
                 else
                   @join_dependency.table_aliases[name] += 1
                 end

activerecord/lib/active_record/relation/finder_methods.rb

@@ -188,7 +188,6 @@ module ActiveRecord
     def construct_relation_for_association_calculations
       including = (@eager_load_values + @includes_values).uniq
       join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, including, arel.joins(arel))
-
       relation = except(:includes, :eager_load, :preload)
       apply_join_dependency(relation, join_dependency)
     end

activerecord/lib/active_record/relation/query_methods.rb

@@ -80,48 +80,14 @@ module ActiveRecord
       @arel ||= build_arel
     end
 
-    def build_arel
+    def custom_join_sql(*joins)
       arel = table
-
-      joined_associations = []
-      association_joins = []
-
-      joins = @joins_values.map {|j| j.respond_to?(:strip) ? j.strip : j}.uniq
-
-      # Build association joins first
-      joins.each do |join|
-        association_joins << join if [Hash, Array, Symbol].include?(join.class) && !array_of_strings?(join)
-      end
-
-      if association_joins.any?
-        join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, association_joins.uniq, nil)
-        to_join = []
-
-        join_dependency.join_associations.each do |association|
-          if (association_relation = association.relation).is_a?(Array)
-            to_join << [association_relation.first, association.association_join.first]
-            to_join << [association_relation.last, association.association_join.last]
-          else
-            to_join << [association_relation, association.association_join]
-          end
-        end
-
-        to_join.each do |tj|
-          unless joined_associations.detect {|ja| ja[0] == tj[0] && ja[1] == tj[1] }
-            joined_associations << tj
-            arel = arel.join(tj[0]).on(*tj[1])
-          end
-        end
-      end
-
       joins.each do |join|
         next if join.blank?
 
         @implicit_readonly = true
 
         case join
-        when Relation::JoinOperation
-          arel = arel.join(join.relation, join.join_class).on(*join.on)
         when Hash, Array, Symbol
           if array_of_strings?(join)
             join_string = join.join(' ')
@@ -131,6 +97,51 @@ module ActiveRecord
           arel = arel.join(join)
         end
       end
+      arel.joins(arel)
+    end
+
+    def build_arel
+      arel = table
+
+      joined_associations = []
+      association_joins = []
+
+      joins = @joins_values.map {|j| j.respond_to?(:strip) ? j.strip : j}.uniq
+
+      joins.each do |join|
+        association_joins << join if [Hash, Array, Symbol].include?(join.class) && !array_of_strings?(join)
+      end
+
+      stashed_association_joins = joins.select {|j| j.is_a?(ActiveRecord::Associations::ClassMethods::JoinDependency::JoinAssociation)}
+
+      non_association_joins = (joins - association_joins - stashed_association_joins).reject {|j| j.blank?}
+      custom_joins = custom_join_sql(*non_association_joins)
+
+      join_dependency = ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, association_joins, custom_joins)
+
+      join_dependency.graft(*stashed_association_joins)
+
+      @implicit_readonly = true unless association_joins.empty? && stashed_association_joins.empty?
+
+      to_join = []
+
+      join_dependency.join_associations.each do |association|
+        if (association_relation = association.relation).is_a?(Array)
+          to_join << [association_relation.first, association.join_class, association.association_join.first]
+          to_join << [association_relation.last, association.join_class, association.association_join.last]
+        else
+          to_join << [association_relation, association.join_class, association.association_join]
+        end
+      end
+
+      to_join.each do |tj|
+        unless joined_associations.detect {|ja| ja[0] == tj[0] && ja[1] == tj[1] && ja[2] == tj[2] }
+          joined_associations << tj
+          arel = arel.join(tj[0], tj[1]).on(*tj[2])
+        end
+      end
+
+      arel = arel.join(custom_joins)
 
       @where_values.uniq.each do |where|
         next if where.blank?

activerecord/test/cases/associations/cascaded_eager_loading_test.rb

@@ -29,6 +29,15 @@ class CascadedEagerLoadingTest < ActiveRecord::TestCase
     assert_equal 2, authors[1].categorizations.size
   end
 
+  def test_eager_association_loading_with_hmt_does_not_table_name_collide_when_joining_associations
+    assert_nothing_raised do
+      Author.joins(:posts).eager_load(:comments).where(:posts => {:taggings_count => 1}).all
+    end
+    authors = Author.joins(:posts).eager_load(:comments).where(:posts => {:taggings_count => 1}).all
+    assert_equal 1, assert_no_queries { authors.size }
+    assert_equal 9, assert_no_queries { authors[0].comments.size }
+  end
+
   def test_eager_association_loading_with_cascaded_two_levels_with_two_has_many_associations
     authors = Author.find(:all, :include=>{:posts=>[:comments, :categorizations]}, :order=>"authors.id")
     assert_equal 2, authors.size