Merge branch 'master' into experiment

* master: (49 commits)
  avoid creating a set if no where values are removed
  remove bind values for where clauses that were removed
  push partitioning up so bind elimination can get the removed wheres
  push partion logic down and initialization logic up
  the rake task `db:test:prepare` needs to load the configuration
  In batches test @total was assigned but not used. Use it in tests instead of Post.count
  partition the where values so we can access the removed ones
  eliminate some conditionals
  change method name to reflect what it actually does.
  save the where values in variables so we don't need to look them up all the time
  pass where values to the helper function rather than rely on internal state
  Spelling correction in Upgrading Guide
  Add has_named_route? to the mapper API
  No need CHANGELOG entry for a test fix
  Fix wrong `case_sensitive` in uniqueness validity test
  Fix typo in test name and documentation
  Missing ending ``` at 14.2 Merging of scopes
  copy edits[ci skip]
  Revert "Corrected documentation and added some more for the classify method in inflectors"
  Revert "Changed the CHANGELOG for active_support and improved the doc for inflector method classify"
  ...

8 files changed, 62 insertions, 33 deletions

diff --git a/activerecord/lib/active_record/associations/builder/association.rb b/activerecord/lib/active_record/associations/builder/association.rb
index 5c37f42794..6a3658f328 100644
--- a/activerecord/lib/active_record/associations/builder/association.rb
+++ b/activerecord/lib/active_record/associations/builder/association.rb
@@ -1,3 +1,15 @@
+# This is the parent Association class which defines the variables
+# used by all associations.
+#
+# The hierarchy is defined as follows:
+#  Association 
+#    - SingularAssociation
+#      - BelongsToAssociation
+#      - HasOneAssociation
+#    - CollectionAssociation
+#      - HasManyAssociation
+#      - HasAndBelongsToManyAssociation
+
 module ActiveRecord::Associations::Builder
   class Association #:nodoc:
     class << self
@@ -58,6 +70,13 @@ module ActiveRecord::Associations::Builder
     def validate_options
       options.assert_valid_keys(valid_options)
     end
+    
+    # Defines the setter and getter methods for the association
+    # class Post < ActiveRecord::Base
+    #   has_many :comments
+    # end
+    # 
+    # Post.first.comments and Post.first.comments= methods are defined by this method...
 
     def define_accessors
       define_readers
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
index fdead16761..9c6690b721 100644
--- a/activerecord/lib/active_record/associations/builder/collection_association.rb
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -1,3 +1,5 @@
+# This class is inherited by the has_many and has_many_and_belongs_to_many association classes 
+
 require 'active_record/associations'
 
 module ActiveRecord::Associations::Builder
@@ -66,6 +68,8 @@ module ActiveRecord::Associations::Builder
       model.send("#{full_callback_name}=", Array(options[callback_name.to_sym]))
     end
 
+    # Defines the setter and getter methods for the collection_singular_ids.
+
     def define_readers
       super
 
diff --git a/activerecord/lib/active_record/associations/builder/singular_association.rb b/activerecord/lib/active_record/associations/builder/singular_association.rb
index f06426a09d..96ccbeb8a3 100644
--- a/activerecord/lib/active_record/associations/builder/singular_association.rb
+++ b/activerecord/lib/active_record/associations/builder/singular_association.rb
@@ -1,3 +1,5 @@
+# This class is inherited by the has_one and belongs_to association classes 
+
 module ActiveRecord::Associations::Builder
   class SingularAssociation < Association #:nodoc:
     def valid_options
@@ -13,6 +15,8 @@ module ActiveRecord::Associations::Builder
       define_constructors if constructable?
     end
 
+    # Defines the (build|create)_association methods for belongs_to or has_one association
+    
     def define_constructors
       mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
         def build_#{name}(*args, &block)
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 2a00ac1386..efd7ecb97c 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -237,11 +237,11 @@ module ActiveRecord
         end
       end
 
-      # Destroy +records+ and remove them from this association calling
-      # +before_remove+ and +after_remove+ callbacks.
+      # Deletes the +records+ and removes them from this association calling
+      # +before_remove+ , +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
       #
-      # Note that this method will _always_ remove records from the database
-      # ignoring the +:dependent+ option.
+      # Note that this method removes records from the database ignoring the
+      # +:dependent+ option.
       def destroy(*records)
         records = find(records) if records.any? { |record| record.kind_of?(Fixnum) || record.kind_of?(String) }
         delete_or_destroy(records, :destroy)
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 71b64de5ea..e82c195335 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -422,9 +422,9 @@ module ActiveRecord
         @association.delete_all
       end
 
-      # Deletes the records of the collection directly from the database.
-      # This will _always_ remove the records ignoring the +:dependent+
-      # option.
+      # Deletes the records of the collection directly from the database
+      # ignoring the +:dependent+ option. It invokes +before_remove+,
+      # +after_remove+ , +before_destroy+ and +after_destroy+ callbacks.
       #
       #   class Person < ActiveRecord::Base
       #     has_many :pets
diff --git a/activerecord/lib/active_record/querying.rb b/activerecord/lib/active_record/querying.rb
index f78ccb01aa..3d85898c41 100644
--- a/activerecord/lib/active_record/querying.rb
+++ b/activerecord/lib/active_record/querying.rb
@@ -14,7 +14,7 @@ module ActiveRecord
     # Executes a custom SQL query against your database and returns all the results. The results will
     # be returned as an array with columns requested encapsulated as attributes of the model you call
     # this method from. If you call <tt>Product.find_by_sql</tt> then the results will be returned in
-    # a Product object with the attributes you specified in the SQL query.
+    # a +Product+ object with the attributes you specified in the SQL query.
     #
     # If you call a complicated SQL query which spans multiple tables the columns specified by the
     # SELECT will be attributes of the model, whether or not they are columns of the corresponding
@@ -29,9 +29,10 @@ module ActiveRecord
     #   Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id"
     #   # => [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
     #
-    #   # You can use the same string replacement techniques as you can with ActiveRecord#find
+    # You can use the same string replacement techniques as you can with <tt>ActiveRecord::QueryMethods#where</tt>:
+    #
     #   Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date]
-    #   # => [#<Post:0x36bff9c @attributes={"title"=>"The Cheap Man Buys Twice"}>, ...]
+    #   Post.find_by_sql ["SELECT body FROM comments WHERE author = :user_id OR approved_by = :user_id", { :user_id => user_id }]
     def find_by_sql(sql, binds = [])
       result_set = connection.select_all(sanitize_sql(sql), "#{name} Load", binds)
       column_types = {}
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index 434af3c5f8..f69e9b2217 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -360,7 +360,7 @@ db_namespace = namespace :db do
     end
 
     # desc 'Check for pending migrations and load the test schema'
-    task :prepare do
+    task :prepare => :load_config do
       unless ActiveRecord::Base.configurations.blank?
         db_namespace['test:load'].invoke
       end
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index eea43aff0e..c114ea0c0d 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -99,8 +99,15 @@ module ActiveRecord
       end
 
       def merge_multi_values
-        relation.where_values = merged_wheres
-        relation.bind_values  = merged_binds
+        lhs_wheres = relation.where_values
+        rhs_wheres = values[:where] || []
+        lhs_binds  = relation.bind_values
+        rhs_binds  = values[:bind] || []
+
+        removed, kept = partition_overwrites(lhs_wheres, rhs_wheres)
+
+        relation.where_values = kept + rhs_wheres
+        relation.bind_values  = filter_binds(lhs_binds, removed) + rhs_binds
 
         if values[:reordering]
           # override any order specified in the original relation
@@ -123,33 +130,27 @@ module ActiveRecord
         end
       end
 
-      def merged_binds
-        if values[:bind]
-          (relation.bind_values + values[:bind]).uniq(&:first)
-        else
-          relation.bind_values
-        end
-      end
-
-      def merged_wheres
-        values[:where] ||= []
+      def filter_binds(lhs_binds, removed_wheres)
+        return lhs_binds if removed_wheres.empty?
 
-        if values[:where].empty? || relation.where_values.empty?
-          relation.where_values + values[:where]
-        else
-          sanitized_wheres + values[:where]
-        end
+        set = Set.new removed_wheres.map { |x| x.left.name }
+        lhs_binds.dup.delete_if { |col,_| set.include? col.name }
       end
 
       # Remove equalities from the existing relation with a LHS which is
       # present in the relation being merged in.
-      def sanitized_wheres
-        seen = Set.new
-        values[:where].each do |w|
-          seen << w.left if w.respond_to?(:operator) && w.operator == :==
+      # returns [things_to_remove, things_to_keep]
+      def partition_overwrites(lhs_wheres, rhs_wheres)
+        if lhs_wheres.empty? || rhs_wheres.empty?
+          return [[], lhs_wheres]
+        end
+
+        nodes = rhs_wheres.find_all do |w|
+          w.respond_to?(:operator) && w.operator == :==
         end
+        seen = Set.new(nodes) { |node| node.left }
 
-        relation.where_values.reject do |w|
+        lhs_wheres.partition do |w|
           w.respond_to?(:operator) && w.operator == :== && seen.include?(w.left)
         end
       end