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.

Remove unnecessary db call when replacing.

Replace map.flatten(1) with flat_map

Avoid namespacing routes inside engines

when an exception happens in an action before the response has been
committed, then we should re-raise the exception in the main thread.
This lets us reuse the existing exception handling.

detect the type of controller we're testing and return the right type of
response based on that controller.  This allows us to stop doing the
weird sleep thing.

When replacing a has_many association with the same one, there is no
need to do a round-trip to the db to create/and drop a new transaction.

[fixes #14220]

use `secrets.secret_key_base` instead of `config.secret_key_base`

use secrets.yml instead of secret_token.rb

Correct `select` examples and doc, ref [522c0fdb] [ci skip]

Fix a few typos. #present_in has been changed to #presence_in through
commit d61baee5.

`includes` uses SQL parsing when String joins are involved.

Use secrets.yml instead of secret_token.rb in the docs

This is a partial revert of 22b3481b.
The current implementation of `references_eager_loaded_tables?` needs to know
every table involved in the query. With the current API this is not possible
without SQL parsing.

While a2dab46c deprecated SQL parsing for `includes`.
It did not issue deprecation warnings when String joins are involved. This resulted
in a breaking change after the deprecated behavior was removed (22b3481b).

We will need to rethink the usage of `includes`, `preload` and `eager_load` but for now,
this brings back the old *working* behavior.

Fix a bug affecting validations of enum attributes

This fixes a bug where any enum attribute of a model
would be evaluated always as 0 when calling the
database on validations.

This fix converts the value of the enum attribute
to its integer value rather than the string before
building the relation as the bug occured when the
string finally gets converted to integer using
string.to_i which converts it to 0.

[Vilius Luneckas, Ahmed AbouElhamayed]

fix test cases

Active Record is specifically for databases. Refs #12101.

Cache#fetch_multi returns a Hash instead of an Array

The current implementation of `fetch_multi` returns an array and has no
means to easily backtrack which names yielded which results. By changing
the return value to a Hash we retain the name information. Hash#values
can be used on the response if only the values are needed.

[skip ci] Fixes docs typo in nested resource path helpers

Now that Validator #setup is called from the initializer, we need a
reference to the model's class to be passed in to allow the validators
to continue functioning when used at the instance level.

Closes #14134.

Goes along with fea1cdcf and
59ec4562.

Fix controller test not resetting @_url_options

Benchmark:

Benchmark.ips do |x|
  x.report("home")       { "home".underscore }
  x.report("Home")       { "Home".underscore }
  x.report("homeBase")   { "homeBase".underscore }
  x.report("home::base") { "home::base".underscore }
end

Before:

Calculating -------------------------------------
                home      2598 i/100ms
                Home      2463 i/100ms
            homeBase      2300 i/100ms
          home::base      2086 i/100ms
-------------------------------------------------
                home    28522.3 (±14.7%) i/s -     140292 in   5.065102s
                Home    29165.8 (±14.9%) i/s -     140391 in   5.000475s
            homeBase    26218.5 (±7.1%) i/s -     131100 in   5.030485s
          home::base    27712.3 (±5.9%) i/s -     139762 in   5.064077s

After:

Calculating -------------------------------------
                home     23163 i/100ms
                Home      2432 i/100ms
            homeBase      2160 i/100ms
          home::base      2265 i/100ms
-------------------------------------------------
                home  1501614.8 (±10.2%) i/s -    7412160 in   5.009540s
                Home    28754.0 (±8.5%) i/s -     143488 in   5.033886s
            homeBase    25331.1 (±5.6%) i/s -     127440 in   5.047940s
          home::base    27089.9 (±5.5%) i/s -     135900 in   5.033516s

We should not rely on to_s to return the name of the class