Merge branch 'master' of github.com:rails/rails

2 files changed, 58 insertions, 24 deletions

diff --git a/activerecord/lib/active_record/relation.rb b/activerecord/lib/active_record/relation.rb
index 4aa460a601..530402bf5d 100644
--- a/activerecord/lib/active_record/relation.rb
+++ b/activerecord/lib/active_record/relation.rb
@@ -1,8 +1,8 @@
 module ActiveRecord
   class Relation
     delegate :to_sql, :to => :relation
-    delegate :length, :collect, :find, :map, :each, :to => :to_a
-    attr_reader :relation, :klass
+    delegate :length, :collect, :map, :each, :to => :to_a
+    attr_reader :relation, :klass, :associations_to_preload, :eager_load_associations
 
     def initialize(klass, relation, readonly = false, preload = [], eager_load = [])
       @klass, @relation = klass, relation
@@ -12,6 +12,21 @@ module ActiveRecord
       @loaded = false
     end
 
+    def merge(r)
+      joins(r.relation.joins(r.relation)).
+        group(r.send(:group_clauses).join(', ')).
+        order(r.send(:order_clauses).join(', ')).
+        where(r.send(:where_clause)).
+        limit(r.taken).
+        offset(r.skipped).
+        select(r.send(:select_clauses).join(', ')).
+        eager_load(r.eager_load_associations).
+        preload(r.associations_to_preload).
+        from(r.send(:sources).any? ? r.send(:from_clauses) : nil)
+    end
+
+    alias :& :merge
+
     def preload(*associations)
       create_new_relation(@relation, @readonly, @associations_to_preload + Array.wrap(associations))
     end
@@ -25,23 +40,19 @@ module ActiveRecord
     end
 
     def select(selects)
-      create_new_relation(@relation.project(selects))
+      selects.present? ? create_new_relation(@relation.project(selects)) : create_new_relation
     end
 
-    # TODO : This is temporary. We need .from in Arel.
-    attr_writer :from
     def from(from)
-      relation = create_new_relation
-      relation.from = from
-      relation
+      from.present? ? create_new_relation(@relation.from(from)) : create_new_relation
     end
 
     def group(groups)
-      create_new_relation(@relation.group(groups))
+      groups.present? ? create_new_relation(@relation.group(groups)) : create_new_relation
     end
 
     def order(orders)
-      create_new_relation(@relation.order(orders))
+      orders.present? ? create_new_relation(@relation.order(orders)) : create_new_relation
     end
 
     def reverse_order
@@ -57,11 +68,11 @@ module ActiveRecord
     end
 
     def limit(limits)
-      create_new_relation(@relation.take(limits))
+      limits.present? ? create_new_relation(@relation.take(limits)) : create_new_relation
     end
 
     def offset(offsets)
-      create_new_relation(@relation.skip(offsets))
+      offsets.present? ? create_new_relation(@relation.skip(offsets)) : create_new_relation
     end
 
     def on(join)
@@ -69,7 +80,7 @@ module ActiveRecord
     end
 
     def joins(join, join_type = nil)
-      return self if join.blank?
+      return create_new_relation if join.blank?
 
       join_relation = case join
       when String
@@ -116,7 +127,7 @@ module ActiveRecord
             :conditions => where_clause,
             :limit => @relation.taken,
             :offset => @relation.skipped,
-            :from => @from
+            :from => (@relation.send(:from_clauses) if @relation.send(:sources).any?)
             },
             ActiveRecord::Associations::ClassMethods::JoinDependency.new(@klass, @eager_load_associations, nil))
         end
@@ -289,9 +300,7 @@ module ActiveRecord
     end
 
     def create_new_relation(relation = @relation, readonly = @readonly, preload = @associations_to_preload, eager_load = @eager_load_associations)
-      r = self.class.new(@klass, relation, readonly, preload, eager_load)
-      r.from = @from
-      r
+      self.class.new(@klass, relation, readonly, preload, eager_load)
     end
 
     def where_clause(join_string = "\n\tAND ")
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 2ec8c0d3a2..61fcc7ca46 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -38,7 +38,7 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_scoped_first
-    topics = Topic.scoped
+    topics = Topic.scoped.order('id ASC')
 
     assert_queries(1) do
       2.times { assert_equal "The First Topic", topics.first.title }
@@ -48,7 +48,7 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_loaded_first
-    topics = Topic.scoped
+    topics = Topic.scoped.order('id ASC')
 
     assert_queries(1) do
       topics.all # force load
@@ -244,7 +244,7 @@ class RelationTest < ActiveRecord::TestCase
     author = Author.scoped.find_by_id!(authors(:david).id)
     assert_equal "David", author.name
 
-    assert_raises(ActiveRecord::RecordNotFound) { Author.scoped.find_by_id_and_name!('invalid', 'wt') }
+    assert_raises(ActiveRecord::RecordNotFound) { Author.scoped.find_by_id_and_name!(20, 'invalid') }
   end
 
   def test_dynamic_find_all_by_attributes
@@ -281,7 +281,7 @@ class RelationTest < ActiveRecord::TestCase
     david = authors.find(authors(:david).id)
     assert_equal 'David', david.name
 
-    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find('invalid') }
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find('42') }
   end
 
   def test_find_ids
@@ -294,8 +294,8 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal 'Mary', results[1].name
     assert_equal results, authors.find([authors(:david).id, authors(:mary).id])
 
-    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find(authors(:david).id, 'invalid') }
-    assert_raises(ActiveRecord::RecordNotFound) { authors.find(['invalid', 'oops']) }
+    assert_raises(ActiveRecord::RecordNotFound) { authors.where(:name => 'lifo').find(authors(:david).id, '42') }
+    assert_raises(ActiveRecord::RecordNotFound) { authors.find(['42', 43]) }
   end
 
   def test_exists
@@ -303,7 +303,8 @@ class RelationTest < ActiveRecord::TestCase
     assert davids.exists?
     assert davids.exists?(authors(:david).id)
     assert ! davids.exists?(authors(:mary).id)
-    assert ! davids.exists?("hax'id")
+    assert ! davids.exists?("42")
+    assert ! davids.exists?(42)
 
     fake  = Author.where(:name => 'fake author')
     assert ! fake.exists?
@@ -328,4 +329,28 @@ class RelationTest < ActiveRecord::TestCase
     assert davids.loaded?
   end
 
+  def test_relation_merging
+    devs = Developer.where("salary >= 80000") & Developer.limit(2) & Developer.order('id ASC').where("id < 3")
+    assert_equal [developers(:david), developers(:jamis)], devs.to_a
+
+    dev_with_count = Developer.limit(1) & Developer.order('id DESC') & Developer.select('developers.*')
+    assert_equal [developers(:poor_jamis)], dev_with_count.to_a
+  end
+
+  def test_relation_merging_with_eager_load
+    relations = []
+    relations << (Post.order('comments.id DESC') & Post.eager_load(:last_comment) & Post.scoped)
+    relations << (Post.eager_load(:last_comment) & Post.order('comments.id DESC') & Post.scoped)
+    
+    relations.each do |posts|
+      post = posts.find { |p| p.id == 1 }
+      assert_equal Post.find(1).last_comment, post.last_comment
+    end
+  end
+
+  def test_relation_merging_with_preload
+    [Post.scoped & Post.preload(:author), Post.preload(:author) & Post.scoped].each do |posts|
+      assert_queries(2) { assert posts.first.author }
+    end
+  end
 end