PDFPreviewer became MuPDFPreviewer in 0b717c20.

[ci skip] Use consistent hash syntax in AR docs

[ci skip] fix typo in Active Record Associations guide

[ci skip] Tidy up formatting of (consecutive) examples

AST Guide: install and migrate tasks needed in new app

* PostgreSQL 10 new relkind for partitioned tables

Starting with PostgreSQL 10, we can now have partitioned tables natively

* Add comment

* Remove extra space

* Add test for partition table in postgreSQL10

* Select 'p' for "BASE TABLE" and add a test case
to support PostgreSQL 10 partition tables

* Address RuboCop offense

* Addressed incorrect `postgresql_version`

Fixes #33008.

[Yannick Schutz & Yasuo Honda & Ryuta Kamizono]

Follow up of #33358 for SQLite3.

Sidestep Google Cloud Storage's restrictive per-object rate limit.

Merge pull request #33408 from ycherniavskyi/fix_leaking_special_form_with_attributes_into_html_attributes

Fix leaking special form_with attributes into html attributes

Prevent `RequestEncoder#encode_params` to parse falsey params

Avoid extra scoping in delegating to klass methods in the `scope` block

#33363 has two regressions. First one is that `insert_fixtures_set` is
failed if flags is an array. Second one is that connection flags are not
restored if `set_server_option` is not supported.

use set_server_option if possible

Fix issue with `button_to`'s `to_form_params`

Normalize the date component to 2000-01-01 automatically

5-2-stable: Backport #33361

Backport to `5-2-stable` since the bug was introduced in Rails 5.2,
see 15cb4efa.

Merge pull request #33361 from jhubert/bugfix/fix-added-string-attributes

Fix regression in use of string attribute in the added? method

cherry-pick 05bef140

e4e1b620 broke `to_param` handling:

Related #31201.

If creating custom primary key (like a string) in SQLite, it would also
create an internal index implicitly which named begin with "sqlite_".

It need to be hidden since the internal object names are reserved and
prohibited for public use.

See https://www.sqlite.org/fileformat2.html#intschema

Fixes #33320.

Fix default value for mysql time types with specified precision

Remove vestigial require on ActiveStorage GCSService

new_framework_defaults_5_2.rb is incompatible with load_default "5.2"

`load_default "5.2"` sets
`Rails.application.config.action_view.form_with_generates_ids` to true
but new_framework_defaults_5_2.rb does not mention about it.

refs 36ac675d

Fix route eager loading

Currently, the seen object cache is shared if join nodes have the same
target class. But it is a wrong assumption, we can't share the seen
object cache between different join nodes (e.g. `:readonly_account` and
`:accounts` have the same target class `Account`, but the instances
have the different state `readonly`).

Fixes #26805.
Closes #27737.

Incompatibility of Direct Uploads & Mirror Service

Since #32732 might be fixed only for Rails 6.0, #33255 should be
backported to 5-2-stable directly.

cherry-pick a845ffdb

[Rafael Mendonça França + Stanislas Boyet + bogdanvlviv]

5-2-stable: Fix docs of `assert_enqueued_email_with` [ci skip]

It isn't allowed to execute `assert_enqueued_email_with` without block
See #33243

We might allow to do it in Rails 6.0. See #33258.

This reverts commit a1080821.

Reason: v10.5.0 has been released, and it seems that the issue is fixed.
Ref: https://github.com/nodejs/node/blob/master/doc/changelogs/CHANGELOG_V10.md#10.5.0

Merge pull request #33172 from thomasdziedzic-pd/add-use_authenticated_message_encryption-documentation

add documentation for config.active_support.use_authenticated_message_encryption

* Convert hashes into parameters

Ensure `ActionController::Parameters#transform_values` and
`ActionController::Parameters#transform_values!` converts hashes into
parameters.

* fixup! Convert hashes into parameters

[Rafael Mendonça França + Kevin Sjöberg]

Currently, column aliases which is used for eager loading are calculated
before constructing all table aliases in FROM clause.

`JoinDependency#join_constraints` constructs table aliases for `joins`
first, and then always re-constructs table aliases for eager loading.

If both `joins` and eager loading are given a same table association,
the re-construction would cause the discrepancy between column aliases
and table aliases.

To avoid the discrepancy, the column aliases should be calculated after
all table aliases are constructed.

Fixes #30603.

5-2-stable: Fix `touch` option to behave consistently with `Persistence#touch` method