Additional fix for argument-splat ordering differences.

Explicitly unpack the expanded args to avoid execution order diff.

See #26854

In https://bugs.ruby-lang.org/issues/12860 I argue that MRI's
execution order here is incorrect. The splatting of the 'c' args
should happen before the shift, but it happens after. On JRuby, it
behaves the way you would expect, leading to the 'c' args splat
still containing the block and producing an error like "cannot
convert proc to symbol" when the send attempts to coerce
it.

This patch makes the unpacking order explicit with a multi-assign,
which behaves properly on all implementations I tested.

don't create db directory when skip active_record

Fix copy_time_to: Copy nsec instead of usec

This is a follow up to #25681, specifically this comment:
https://github.com/rails/rails/pull/25681#issuecomment-238294002

The way the thread local variable is stored is an implementation detail
and subject to change. It makes no sense to only generate a reader or
writer as you'd have to know where to read from or where it writes to.

[ci skip]

This was pointed out on
https://github.com/rails/rails/issues/15583#issuecomment-239212831

The comment was lost in the changes made by
fcd0ac06 and
3e1373a7

[ci skip] Fix return values of Hash Extensions examples

The hashes returned in some examples of the following sections had items in a different order than their receivers. That may mislead readers into believing those methods will not preserve element order.

Extensions to Hash/Working with Keys/transform_keys and transform_keys!
Extensions to Hash/Working with Keys/stringify_keys and stringify_keys!
Extensions to Hash/Working with Keys/symbolize_keys and symbolize_keys!
Extensions to Hash/Slicing

Query cache doesn't type cast bind parameters since it isn't
actually querying the database, so it can't pass those values in.  Type
casting in the query cache method would cause the values to be type cast
twice in the case that there is a cache miss (since the methods it calls
will type cast *again*).  If logging is disabled, then adding the type
cast code to the query cache method will needlessly typecast the values
(since the only reason those values are type cast is for display in the
logs).

Fixes #26828.

Mask forking filesystem event on JRuby.

`copy_time_to` is a helper function for date and time calculations.
It's being used by `prev_week`, `next_week` and `prev_weekday` to keep
the time fraction when jumping around between days.

Previously the nanoseconds part was lost during the operation. This
lead to problems in practice if you were using the `end_of_day`
calculation. Resulting in the time fraction of `end_of_day` not being
the same as next week's `end_of_day`.

With this fix `copy_time_to` doesn't forget the `nsec` digits.

Wait for file events to propagated for slower Listen backends.

[ci skip] Fix indentation of code examples

This commit fixes the generated HTML of the two code examples.

update doc about `change_column_default` [ci skip]

Follow up to #20018.

[ci skip] Fix typo in Guides: Contributing

Bump bundler version in the before_install hook of travis

- We were running into issues with old bundler versions on 4.2
  builds. So we bumped the bundler version on 4-2-stable branch in
  https://github.com/rails/rails/pull/26592.
- This commit applies same change to master as per discussion in
  https://github.com/rails/rails/pull/26592#issuecomment-254026755.

Allow any key in Renderer environment hash

[ci skip]

Make `process` a non-private method and update documentation.

initialize errors with name of class and other params

* Clarify the default behavior of log_formatter

Updates language to remove reference to production.rb and fix quoting

When rendering arbitrary templates, it is helpful to not overwrite `env` keys with nil if they don't match any found in the `RACK_KEY_TRANSLATION`

This allows the developer to set the environment to exactly what is needed for rendering.

Introduce a benchmark template

This replaces boilerplate in the “benchmark your code” section of the
contributors’ guide with an executable template. I also amended the text
to encourage best practices and codified it in the template.

For now this is only good for relatively self-contained changes that can
be inlined into a simple script. In the future, this can be expanded to
cover how to measure the difference between two commits.

The output looks like this:

```
==================================== Empty =====================================

Warming up --------------------------------------
              blank?   225.963k i/100ms
         fast_blank?   238.147k i/100ms
Calculating -------------------------------------
              blank?      8.825M (± 6.4%) i/s -     44.063M in   5.014824s
         fast_blank?      9.311M (± 6.3%) i/s -     46.439M in   5.009153s

Comparison:
         fast_blank?:  9310694.8 i/s
              blank?:  8824801.7 i/s - same-ish: difference falls within error


================================= Single Space =================================

Warming up --------------------------------------
              blank?    56.581k i/100ms
         fast_blank?   232.774k i/100ms
Calculating -------------------------------------
              blank?    813.985k (±16.7%) i/s -      4.017M in   5.076576s
         fast_blank?      9.547M (± 5.2%) i/s -     47.719M in   5.013204s

Comparison:
         fast_blank?:  9547414.0 i/s
              blank?:   813985.0 i/s - 11.73x  slower


================================== Two Spaces ==================================

Warming up --------------------------------------
              blank?    58.265k i/100ms
         fast_blank?   244.056k i/100ms
Calculating -------------------------------------
              blank?    823.343k (±16.2%) i/s -      4.020M in   5.014213s
         fast_blank?      9.484M (± 4.9%) i/s -     47.347M in   5.005339s

Comparison:
         fast_blank?:  9484021.6 i/s
              blank?:   823343.1 i/s - 11.52x  slower


=============================== Mixed Whitspaces ===============================

Warming up --------------------------------------
              blank?    53.919k i/100ms
         fast_blank?   237.103k i/100ms
Calculating -------------------------------------
              blank?    763.435k (±16.8%) i/s -      3.720M in   5.018029s
         fast_blank?      9.672M (± 5.8%) i/s -     48.369M in   5.019356s

Comparison:
         fast_blank?:  9672467.2 i/s
              blank?:   763435.4 i/s - 12.67x  slower


=============================== Very Long String ===============================

Warming up --------------------------------------
              blank?    34.037k i/100ms
         fast_blank?   240.366k i/100ms
Calculating -------------------------------------
              blank?    409.731k (± 8.9%) i/s -      2.042M in   5.028235s
         fast_blank?      9.794M (± 4.3%) i/s -     49.035M in   5.016328s

Comparison:
         fast_blank?:  9794225.2 i/s
              blank?:   409731.4 i/s - 23.90x  slower
```

Quote table name properly

Support index.length for MySQL 8.0.0-dmr