This actually not an issue fixing ; the changelog is referring to the
introducing pull request itself.

origin: https://github.com/rails/rails/commit/f6aeb8b1a3687c8523e4a56309fe3736011b2935#commitcomment-5569649

This is a result of the discussion at https://github.com/rails/rails/pull/14263/files#r10291489

This is a follow up to a668beff

Follow up of #10732 - Allow string hash values on AR order method

Make exists? use bound values.

This reverts commit 475c9658, reversing
changes made to 705915ab.

We decided that this is not worth busting everyone's cache as this
seems like a very unlikely problem. The problem only occurs when the
user is 1) not using a namespace, or 2) using the same namesapce for
different *kinds* of cache items. The recommended "fix" is to put
those cache items into their own namspace:

    id = 1
    Rails.cache.fetch(id, namespace: "user"){ User.find(id) }

    ids = [1]
    Rails.cache.fetch(ids, namespace: "users"){ User.find(ids) }

See the discussion on #14269 for details.

Cache key should be different when is Array.

This behavior has almost no performance impact:

String not allowed  66.910000   0.030000  66.940000 ( 67.024976)
String allowed      69.360000   0.030000  69.390000 ( 69.503096)

Benchmarked with http://git.io/Y0YuRw.

Variants in ActionView::Digestor

HAML and probably other generators extend this class and invoke
filename_with_extensions with the old signature (without format).
This makes the second argument optional and defaults it to the #format
method which could be overridden as well.

Closes #14132.

Take variants into account when calculating template digests in
ActionView::Digest.

Digestor#digest now takes a hash as an argument to support variants and
allow more flexibility in the future. Old-style arguments have been
deprecated.

Fixes #14242

Fix enum test unused variable warning.

Related - https://github.com/rails/rails/commit/5c55aafd38f45ac019573f98438ffdbdc8c580f9

Add Enum type to postgresql adapter's oids to prevent unknown OID warnings

There's no need to rely on Active Support's Hash#reverse_merge for
simple cases with default values, since we can just merge from the
default rather than reverse merge from the options.

This also avoids the creation of one extra hash object by moving to a
Hash#merge! call.

Fixes #14254 ActionView button_tag helper default options values issue.

When we build a query with an inline value that is a numeric (e.g.
because it's out of range for an int4) PostgreSQL doesn't use an index
on the column, since it's now comparing numerics and not int4s.

This leads to a _very_ slow query.

When we use bound parameters instead of inline values PostgreSQL
raises numeric_value_out_of_range since no automatic coercion happens.

`cache.fetch(['foo'])` and `cache.fetch('foo')` should generate
different cache keys as they are not equivalents.

[related #8615]
[related #8614]

Add spaces to the log message of ActionController:: LogSubscriber#deep_munge

The 'cow' => 'kine' inflection has gone with c300dca9 but it should
not be removed from the tested irregularities since it ensures that
inflections work with words that do not begin with the same letters.

Refactor actionpack ActionDispatch::Request tests

Fix PG warnings.

- unused variable in PG Adapter.
- Ambiguous argument warning from range_test for use - to + Infinity range without brackets.