Merge branch 'master' into set_binds

* master: (2794 commits)
  doc, API example on how to use `Model#exists?` with multiple IDs. [ci skip]
  Restore DATABASE_URL even if it's nil in connection_handler test
  [ci skip] - error_messages_for has been deprecated since 2.3.8 - lets reduce any confusion for users
  Ensure Active Record connection consistency
  Revert "ask the fixture set for the sql statements"
  Check `respond_to` before delegation due to: https://github.com/ruby/ruby/commit/d781caaf313b8649948c107bba277e5ad7307314
  Adding Hash#compact and Hash#compact! methods
  MySQL version 4.1 was EOL on December 31, 2009 We should at least recommend modern versions of MySQL to users.
  clear cache on body close so that cache remains during rendering
  add a more restricted codepath for templates fixes #13390
  refactor generator tests to use block form of Tempfile
  Fix typo [ci skip]
  Move finish_template as the last public method in the generator
  Minor typos fix [ci skip]
  make `change_column_null` reversible. Closes #13576.
  create/drop test and development databases only if RAILS_ENV is nil
  Revert "Speedup String#to"
  typo fix in test name. [ci skip].
  `core_ext/string/access.rb` test what we are documenting.
  Fix typo in image_tag documentation
  ...

Conflicts:
	activerecord/lib/active_record/associations/join_dependency/join_association.rb
	activerecord/lib/active_record/relation/query_methods.rb

1 files changed, 57 insertions, 13 deletions

diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index a8905ed739..4669c072a1 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -10,9 +10,6 @@ module ActiveRecord
       # The +attributes+ parameter can be either a Hash or an Array of Hashes. These Hashes describe the
       # attributes on the objects that are to be created.
       #
-      # +create+ respects mass-assignment security and accepts either +:as+ or +:without_protection+ options
-      # in the +options+ parameter.
-      #
       # ==== Examples
       #   # Create a single new object
       #   User.create(first_name: 'Jamie')
@@ -184,6 +181,7 @@ module ActiveRecord
       became = klass.new
       became.instance_variable_set("@attributes", @attributes)
       became.instance_variable_set("@attributes_cache", @attributes_cache)
+      became.instance_variable_set("@changed_attributes", @changed_attributes) if defined?(@changed_attributes)
       became.instance_variable_set("@new_record", new_record?)
       became.instance_variable_set("@destroyed", destroyed?)
       became.instance_variable_set("@errors", errors)
@@ -267,7 +265,7 @@ module ActiveRecord
     # This method raises an +ActiveRecord::ActiveRecordError+ when called on new
     # objects, or when at least one of the attributes is marked as readonly.
     def update_columns(attributes)
-      raise ActiveRecordError, "can not update on a new record object" unless persisted?
+      raise ActiveRecordError, "cannot update on a new record object" unless persisted?
 
       attributes.each_key do |key|
         verify_readonly_attribute(key.to_s)
@@ -333,10 +331,54 @@ module ActiveRecord
       toggle(attribute).update_attribute(attribute, self[attribute])
     end
 
-    # Reloads the attributes of this object from the database.
-    # The optional options argument is passed to find when reloading so you
-    # may do e.g. record.reload(lock: true) to reload the same record with
-    # an exclusive row lock.
+    # Reloads the record from the database.
+    #
+    # This method finds record by its primary key (which could be assigned manually) and
+    # modifies the receiver in-place:
+    #
+    #   account = Account.new
+    #   # => #<Account id: nil, email: nil>
+    #   account.id = 1
+    #   account.reload
+    #   # Account Load (1.2ms)  SELECT "accounts".* FROM "accounts" WHERE "accounts"."id" = $1 LIMIT 1  [["id", 1]]
+    #   # => #<Account id: 1, email: 'account@example.com'>
+    #
+    # Attributes are reloaded from the database, and caches busted, in
+    # particular the associations cache.
+    #
+    # If the record no longer exists in the database <tt>ActiveRecord::RecordNotFound</tt>
+    # is raised. Otherwise, in addition to the in-place modification the method
+    # returns +self+ for convenience.
+    #
+    # The optional <tt>:lock</tt> flag option allows you to lock the reloaded record:
+    #
+    #   reload(lock: true) # reload with pessimistic locking
+    #
+    # Reloading is commonly used in test suites to test something is actually
+    # written to the database, or when some action modifies the corresponding
+    # row in the database but not the object in memory:
+    #
+    #   assert account.deposit!(25)
+    #   assert_equal 25, account.credit        # check it is updated in memory
+    #   assert_equal 25, account.reload.credit # check it is also persisted
+    #
+    # Another common use case is optimistic locking handling:
+    #
+    #   def with_optimistic_retry
+    #     begin
+    #       yield
+    #     rescue ActiveRecord::StaleObjectError
+    #       begin
+    #         # Reload lock_version in particular.
+    #         reload
+    #       rescue ActiveRecord::RecordNotFound
+    #         # If the record is gone there is nothing to do.
+    #       else
+    #         retry
+    #       end
+    #     end
+    #   end
+    #
     def reload(options = nil)
       clear_aggregation_cache
       clear_association_cache
@@ -349,14 +391,16 @@ module ActiveRecord
         end
 
       @attributes.update(fresh_object.instance_variable_get('@attributes'))
-      @columns_hash = fresh_object.instance_variable_get('@columns_hash')
 
-      @attributes_cache = {}
+      @column_types           = self.class.column_types
+      @column_types_override  = fresh_object.instance_variable_get('@column_types_override')
+      @attributes_cache       = {}
       self
     end
 
     # Saves the record with the updated_at/on attributes set to the current time.
-    # Please note that no validation is performed and no callbacks are executed.
+    # Please note that no validation is performed and only the +after_touch+
+    # callback is executed.
     # If an attribute name is passed, that attribute is updated along with
     # updated_at/on attributes.
     #
@@ -383,7 +427,7 @@ module ActiveRecord
     #   ball.touch(:updated_at)   # => raises ActiveRecordError
     #
     def touch(name = nil)
-      raise ActiveRecordError, "can not touch on a new record object" unless persisted?
+      raise ActiveRecordError, "cannot touch on a new record object" unless persisted?
 
       attributes = timestamp_attributes_for_update_in_model
       attributes << name if name
@@ -399,7 +443,7 @@ module ActiveRecord
 
         changes[self.class.locking_column] = increment_lock if locking_enabled?
 
-        @changed_attributes.except!(*changes.keys)
+        changed_attributes.except!(*changes.keys)
         primary_key = self.class.primary_key
         self.class.unscoped.where(primary_key => self[primary_key]).update_all(changes) == 1
       end