Merged in f41dba27
[ci skip]

postgres, map scaled intervals to string datatype

* There is no need to delete the primary key from cloned attributes,
  since it sets the same pk to nil afterwards.
* Check for empty? instead of any? to run initialize callbacks.

Improve error message for memcache session store when dalli isn't loaded

transaction.

Check 0180e090 for more reasoning about
that.

Check 0180e090 for more reasoning about
that.

Due to a change in builder, nil values and empty strings now generates
closed tags, so instead of this:

    <pseudonyms nil=\"true\"></pseudonyms>

It generates this:

    <pseudonyms nil=\"true\"/>

Document this change in Rails so that people can track it down easily if
necessary.

Since 810a50da, the new policy is to
keep old changelogs in their own branches, to avoid manual syncing
across different branches.

Please check that commit for more reasoning about the new policy.

Use Dalli for memcache session store

AS::Callbacks: deprecate monkey patch of object callbacks

Fix eagerly loading associations without primary keys

There is no memcache gem left in repo.

Fix Changelog example in Action Mailer [ci skip]

Update Active Record CHANGELOG for #7419 [ci skip]

Ensure valid migration filename on generating migration

move validation to AR

Fixed around callback with lambda example

This is a follow up to issue #7535

I have also chosen a variable name that matches the
parameter in the definition of load_missing_constant.

Those who say source code should be without comments lie.

Basically, const_missing had a loop to try parent namespaces
if the constant lookup failed, but at the same time delegated
to load_missing_constant which in turn also walks up parent
namespaces calling const_missing by hand. In the case of missing
constants this results in repeated work in some funky nested way.

Allow delivery method options to be set per mail instance

This will solve the issue that abort the connection transaction when we
skip the tests.

AR supporting new JSON data type on PostgreSQL >= 9.2