Improvement in ActiveRecord::Persistence doc [ci skip]

Fix doc

Revert "Eliminate the EventMachine dependency"

remove duplication section [ci skip]

[ci skip]

We found that inserting all 600 schema_migrations for our mid-sized app takes about a minute on a cloud based CI environment.

I assume that the original code did not use multi-row-insert because SQLite3 was not supporting the syntax back then,
but it's been supported since 3.7.11: http://www.sqlite.org/releaselog/3_7_11.html

Fix undefined error for `ActionController::Parameters`

These tests were failing due to backwards incompatible changes, as apart
of the v1.0.3 release of rails-html-sanitizer.

The cache for `render file:` seems to also be used in the case of
`render(string)`.  If one is supposed to be a hit and the other is
supposed to be a miss, and they both reference the same file, then the
cache could return incorrect values.  This commit clears the cache
between runs so that we get non-cached behavior.

documentation fix

[ci skip] Don’t explicitly mention EventMachine

Since #23152 eliminated the EventMachine dependency, we don’t need to
explicitly mention EventMachine.

Nevertheless, I'm not 100% sure about saying "the websocket-driver loop"
driver… any suggestions, @matthewd or @pixeltrix ? 😅

[ci skip]

Update `Gemfile.lock`

* 5-0-beta-sec:
  bumping version
  fix version update task to deal with .beta1.1
  Eliminate instance level writers for class accessors
  allow :file to be outside rails root, but anything else must be inside the rails view directory
  Don't short-circuit reject_if proc
  stop caching mime types globally
  use secure string comparisons for basic auth username / password

Fix nodoc to internal class error document some of them

[ci skip]
Fixes #20808

[Vipul A M & Julio Lopez]

[close #23009] Limit key length

Pass 2 over testing guide

When verifying size of relation, also verify count is ok.

Change permission to readonly [ci skip]

Add missing source_type if provided on hmt which belongs to an sti re…

Fix AR::Relation#cache_key to remove select scope added by user

This reverts commit 62aa850f, reversing
changes made to 8c1f248c.

There is no reason to disallow mail 2.5 so we don't need to bump the
version constraint since people are still able to use mail 2.6 and get
all the memory saving that was pointed in the pull request description.

ActionCable: Allow adding custom paths for channels

- We don't need the select scope added by user as we only want to max
  timestamp and size of the collection. So we already know which columns
  to select.
- Additionally having user defined columns in select scope blows the cache_key
  method with PostGreSQL because it needs all `selected` columns in the group_by
  clause or aggregate function.
- Fixes #23038.

Fixes #23209

Bump mail gem constraint from [~> 2.5, >= 2.5.4] to ~> 2.6

Fix ActiveRecord::Relation#cache_key for relations with no results