Fixes #32610. Closes #32614.

Lua scripts in redis are *blocking*, meaning that no other client can
execute any commands while the script is running. See
https://redis.io/commands/eval#atomicity-of-scripts.

This results in the following exceptions once the number of keys is
sufficiently large:

    BUSY Redis is busy running a script.
    You can only call SCRIPT KILL or SHUTDOWN NOSAVE.

This commit replaces the lua-based implementation with one that uses
`SCAN` and `DEL` in batches. This doesn't block the server.

The primary limitation of `SCAN`, i.e. potential duplicate keys, is of
no consequence here, because `DEL` ignores keys that do not exist.

Before this change missing timezone data for any of the time zones
defined in `ActiveSupport::Timezone::MAPPING` caused a `comparison of
NilClass with ActiveSupport::TimeZone failed` exception.

Attempting to get a timezone by passing a number/duration to `[]` or
calling `all` directly will try to sort sort the values of `zones_map`.
Those values are initialized by the return value of `create(zonename)`
which returns `nil` if `TZInfo` is unable to find the timezone
information.

In our case the exception was triggered by an outdated tzdata package
which did not include information for the "recently" added time zones.

Before 078421ba `zones_map` only
returned the information that have been loaded into `@lazy_zone_map`
which ignored time zones for which the data could not be loaded, this
change restores the previous behaviour.

(See previous commit for a description of the issue)

We only add the header when releasing to avoid some conflicts.

[ci skip]

- Add missing dots.
- Remove reference to itself on GitHub.
  Usually, we add references to fixed issues only in a changelog.

Follow up #32223

Equality comparisons between dates and times can take some extra time to
comprehend. I tend to think of a date or time as "before" or "after"
another date or time, but I naturally read `<` and `>` as "less than"
and "greater than." This change seeks to make date/time comparisons more
human readable.

Previously, URI.enscape could handle Unicode input (without any actual
escaped characters), or input with escaped characters (but no actual
Unicode characters) - not both.

    URI.unescape("\xe3\x83\x90")  # => "バ"
    URI.unescape("%E3%83%90")  # => "バ"
    URI.unescape("\xe3\x83\x90%E3%83%90")  # =>
                                         # Encoding::CompatibilityError

We need to let `gsub` handle this for us, and then force back to the
original encoding of the input.  The result String will be mangled if
the percent-encoded characters don't conform to the encoding of the
String itself, but that goes without saying.
Signed-off-by: NAshe Connor <ashe@kivikakk.ee>

now support translations through I18n.

        {
          fr: {
            number: {
              nth: {
                ordinals: lambda do |_key, number:, **_options|
                  if number.to_i.abs == 1
                    'er'
                  else
                    'e'
                  end
                end,

                ordinalized: lambda do |_key, number:, **_options|
                  "#{number}#{ActiveSupport::Inflector.ordinal(number)}"
                end
              }
            }
          }
        }

Remove extra comments `# Asking for private method` in activesupport/test/core_ext/module_test.rb
Improve docs of using `delegate` with `:private`
Update changelog of #31944

Previously it was removed by #32106 since it was backported to `5-2-stable`.

[ci skip]

Remove railties' changelog added by 7340596d
since it was backported to `5-2-stable` via ac99916f

Remove activesupport's changelog added by 1077ae96
since it was backported to `5-2-stable` via a2b97e4f

Remove activesupport's changelog added by 0d41a76d
since it was backported to `5-2-stable` via cdce6a70

Remove activestorage's changelog added by d57c52a3
since it was backported to `5-2-stable` via 5292cdf5

Follow up c113bdc9

Fixes #31909.
Closes #31911.

Some timezones like `Europe/London` have multiple mappings in
`ActiveSupport::TimeZone::MAPPING` so return all of them instead
of the first one found by using `Hash#value`. e.g:

  # Before
  ActiveSupport::TimeZone.country_zones("GB") # => ["Edinburgh"]

  # After
  ActiveSupport::TimeZone.country_zones("GB") # => ["Edinburgh", "London"]

Fixes #31668.

This faithfully preserves grapheme clusters (characters composed of other
characters and combining marks) and other multibyte characters.

```ruby
"foo".freeze.strip_heredoc.frozen?  # => true
```

Fixes the case where frozen string literals would inadvertently become
unfrozen:

```ruby

foo = <<-MSG.strip_heredoc
  la la la
MSG

foo.frozen?  # => false !??
```

Skipping over 2.4.0 to sidestep the `"symbol_from_string".to_sym.dup` bug.

References #32028

Provides both a forked process and threaded parallelization options. To
use add `parallelize` to your test suite.

Takes a `workers` argument that controls how many times the process
is forked. For each process a new database will be created suffixed
with the worker number; test-database-0 and test-database-1
respectively.

If `ENV["PARALLEL_WORKERS"]` is set the workers argument will be ignored
and the environment variable will be used instead. This is useful for CI
environments, or other environments where you may need more workers than
you do for local testing.

If the number of workers is set to `1` or fewer, the tests will not be
parallelized.

The default parallelization method is to fork processes. If you'd like to
use threads instead you can pass `with: :threads` to the `parallelize`
method. Note the threaded parallelization does not create multiple
database and will not work with system tests at this time.

parallelize(workers: 2, with: :threads)

The threaded parallelization uses Minitest's parallel exector directly.
The processes paralleliztion uses a Ruby Drb server.

For parallelization via threads a setup hook and cleanup hook are
provided.

```
class ActiveSupport::TestCase
  parallelize_setup do |worker|
    # setup databases
  end

  parallelize_teardown do |worker|
    # cleanup database
  end

  parallelize(workers: 2)
end
```

[Eileen M. Uchitelle, Aaron Patterson]

:tada::tada::tada:

* Support hash as first argument for `assert_difference`.

This allows to specify multiple numeric differences in the same assertion.
Example:

    assert_difference 'Article.count' => 1, 'Notification.count' => 2 do
      # post :create, params: { article: {...} }
    end

* Support error message when passing a hash as a first parameter

* Format CHANGELOG properly

[Julien Meichelbeck + Rafael Mendonça França]

Instead of providing a configuration option to set the hash function,
switch to SHA-1 for new apps and allow upgrading apps to opt in later
via `new_framework_defaults_5_2.rb`.

currently it's not possible to know what the hit rates are from read_multi

Using `truncate` to limit the length of the digest has the unwanted side
effect of adding an ellipsis when the input is longer than the limit.

Also:
 - Don't instantiate a new object for every digest
 - Rename the configuration option to `hash_digest_class`
 - Update the CHANGELOG entry to describe how to use the feature

and defaults to `Digest::MD5`.

Replaced calls to `::Digest::MD5.hexdigest` with calls to `ActiveSupport::Digest.hexdigest`.

Support `expires_in` in `ActiveSupport::Cache::MemCacheStore#increment`
and `#decrement`.

Closes #30716.

Make `ActiveSupport::TimeWithZone` match Ruby's handling of ambiguous
times by choosing the later period, e.g.

Ruby:
```
ENV["TZ"] = "Europe/Moscow"
Time.local(2014, 10, 26, 1, 0, 0)   # => 2014-10-26 01:00:00 +0300
```

Before:
```
>> "2014-10-26 01:00:00".in_time_zone("Moscow")
TZInfo::AmbiguousTime: 26/10/2014 01:00 is an ambiguous local time.
```

After:
```
>> "2014-10-26 01:00:00".in_time_zone("Moscow")
=> Sun, 26 Oct 2014 01:00:00 MSK +03:00
```

Fixes #17395.

Compression has long been available, but opt-in and at a 16kB threshold.
It wasn't enabled by default due to CPU cost. Today it's cheap and
typical cache data is eminently compressible, such as HTML or JSON
fragments.

Compression dramatically reduces Memcached/Redis mem usage, which means
the same cache servers can store more data, which means higher hit
rates.

To disable compression, pass `compress: false` to the initializer.

* Supports vanilla Redis, hiredis, and Redis::Distributed.
* Supports Memcached-like sharding across Redises with Redis::Distributed.
* Fault tolerant. If the Redis server is unavailable, no exceptions are
  raised. Cache fetches are treated as misses and writes are dropped.
* Local cache. Hot in-memory primary cache within block/middleware scope.
* `read_/write_multi` support for Redis mget/mset. Use Redis::Distributed
  4.0.1+ for distributed mget support.
* `delete_matched` support for Redis KEYS globs.

While using `assert_changes`, I came across some unexpected behavior:
if you provide a `to:` argument, and the expression matches but didn't
actually change, the assertion will pass.

The way `assert_changes` reads, I assumed that it would both assert
that there was any change at all, _and_ that the expression changed to
match my `to:` argument.

In the case of just a `from:` argument, `assert_changes` does what I
expect as well. It asserts that the before value `=== from` and that
the after value changed.

My key change is that `assert_changes` will now _always_ assert that
expression changes, no matter what combination of `from:` and `to:`
arguments

[ci skip]

In #11474 we prevented TWZ ranges being iterated over which matched
Ruby's handling of Time ranges and as a consequence `include?` stopped
working with both Time ranges and TWZ ranges. However in
ruby/ruby@b061634 support was added for `include?` to use `cover?` for
'linear' objects. Since we have no way of making Ruby consider TWZ
instances as 'linear' we have to override `Range#include?`.

Fixes #30799.

Acronym inflections are stored with lowercase keys in the hash but
the match wasn't being lowercased before being looked up in the hash.
This shouldn't have any performance impact because before it would
fail to find the acronym and perform the `downcase` operation anyway.

Fixes #31052.