`migration_keys` includes `name` but `name` is not a column option.

```ruby
  # Before
  t.index ["firm_id", "type", "rating"], name: "company_index", order: {"rating"=>:desc}, using: :btree

  # After
  t.index ["firm_id", "type", "rating"], name: "company_index", order: { rating: :desc }, using: :btree
```

Currently blank comment does not dump to `db/schema.rb`. But created it
even if specified blank.

https://bugs.ruby-lang.org/issues/12739

ActiveModel::Type)

Some code was previously referring to ActiveModel::Type::*. This could
cause issues in the future if any of the ActiveRecord::Type classes were
overridden in the future.

Zlib is used to generate the advisory lock since commit 2c2a8755 .

Using the Migrator fails since then, when it is called without the rails context:

    NameError: uninitialized constant ActiveRecord::Migrator::Zlib

This patch fixes the above error.

We've seen occasional Travis failures mentioning deadlocks. I think
they're escaping from this test.

This was caused by 6d0d83a3. While the
bug it's trying to fix is handled if the association is loaded in an
after_(create|save) callback, it doesn't handle any cases that load the
association before the persistence takes place (validation, or before_*
filters). Instead of caring about the timing of persistence, we can just
ensure that we're not double adding the record instead.

The test from that commit actually broke, but it was not because the bug
has been re-introduced. It was because `Bulb` in our test suite is doing
funky things that look like STI but isn't STI, so equality comparison
didn't happen as the loaded model was of a different class.

Fixes #26661.

`test_native_decimal_insert_manual_vs_automatic` exists inside
`unless current_adapter?(:SQLite3Adapter)`. This condition is
duplicated.

This is not as good a solution as actually hashing both values, but Ruby
doesn't expose that capability other than allocating the array. Unless we were
to do something silly like have a thread local array that is re-used, I don't
see any other way to do this without allocation. This solution may not be
perfect, but it should reasonably avoid collisions to the extent that we need.

Per discussion in pull request #26622:

"Let's change it to PG::Error. The more specific classes mentioned are
subclasses, and the fact the raised exception is a PG::UndefinedColumn
doesn't change the fact that it's also a PG::Error." - matthewd

This clarifies the object that +ActiveRecord::Base.connection.execute+
will return when using Postgresql.

Noticed that the `validate: false` option for `ActiveRecord::Persistence#save` and `#save!` were not formatted as code like the other examples in the documentation.

Test: JSON attribute value nil can be used in where(attr: nil)

Add changelog entry

- If the attribute is not changed, then update_attribute does not run
  SQL query, this effectively means that no change was made to the
  attribute.
- This change was made in https://github.com/rails/rails/commit/0fcd4cf5
  to avoid a SQL call.
- But the change resulted into `nil` being returned when there was no
  change in the attribute value.
- This commit corrects the behavior to return true if there is no change
  in attribute value. This is same as previous behavior of Rails 4.2
  plus benefit of no additional SQL call.
- Fixes #26593.

When the association is autosaved we were storing the details with
string keys. This was creating inconsistency with other details that are
added using the `Errors#add` method. It was also inconsistent with the
`Errors#messages` storage.

To fix this inconsistency we are always storing with symbols. This will
cause a small breaking change because in those cases the details could
be accessed as strings keys but now it can not.

The reason that we chose to do this breaking change is because `#details`
should be considered a low level object like `#messages` is.

Fix #26499.

[Rafael Mendonça França + Marcus Vieira]

assert [1, 3].includes?(2) fails with unhelpful "Asserting failed" message

assert_includes [1, 3], 2 fails with "Expected [1, 3] to include 2" which makes it easier to debug and more obvious what went wrong

[fixes #26441]

Without this the changes to the lock version column will stick around
even after `touch` returns.

Before:

    model.touch
    model.changes
    # => {"lock_version"=>[0, "1"]}

After:

    model.touch
    model.changes
    # {}

All indentation was normalized by rubocop auto-correct at 80e66cc4.
But comments was still kept absolute position. This commit aligns
comments with method definitions for consistency.

* activerecord/mysql2: Avoid setting @connection to nil, just close it

Backport of https://github.com/rails/rails/pull/26434

* Add a CHANGELOG entry

Make name of attribute medium instead of normal

If using namespaced fixtures, get following Ruby warning.

```
activerecord/lib/active_record/fixtures.rb:922: warning: method redefined; discarding old admin_foos
activerecord/lib/active_record/fixtures.rb:922: warning: previous definition of admin_foos was here
```

This is happening because of the multiple set the same path when setting the
fixture name. Fix to remove the duplicate path.

The `elsif` branch is completely duplicated with `else` branch.

Passing `FakeColumn` was removed at #15336 therefore
`test_string_with_crazy_column` is duplicated with
`test_quote_string_no_column`.

`Mutex` was removed at 8eb7561a.

`column_for` was changed to `type_for` to return `type` object at
36bd52b4. But variable name is still `column`. It is very confusing.
Rename variable name `column` to `type` for readability.

This comment was added at eaf54865 but already implemented.