flash doesn't pass objects #15522 [ci skip]
do not hold on to a stale connection object. fixes #15998
Tiny follow-up to #15987 and 088b4c3e [ci skip]
Revert "Merge pull request #15394 from morgoth/fix-automatic-maintaining-test-schema-for-sql-format"

This reverts commit 46139d33c06715e74ad450428ece3ee84da98579, reversing
changes made to 8f247871bb18b2e3036a05df5f62cbfe3b402586.

Conflicts:
	activerecord/CHANGELOG.md
Move pk initialization logic onto `AttributeSet`

Better encapsulates its internals from `ActiveRecord::Base`.
Don't error when `dup`ing a record with no PK
Merge pull request #16007 from nishantmodak/flash_msg_as_string

flash doesn't pass objects #15522 [ci skip]
Merge pull request #16016 from sgrif/sg-dup

Don't error when `dup`ing a record with no PK
Fix typo
Fix SQL injection when querying against ranges and bitstrings

Fix CVE-2014-3483 and protect against CVE-2014-3482.
Quote range strings when quoting PG ranges

The test case for CVE-2014-3483 doesn't actually send the generated SQL
to the database. The generated SQL is actually invalid for real inputs.
Merge pull request #16022 from sgrif/sg-range-quoting

Quote range strings when quoting PG ranges
Merge pull request #16015 from sgrif/sg-ensure-initialized

Move pk initialization logic onto `AttributeSet`

Conflicts:
	activerecord/lib/active_record/attribute_set.rb
automatically include ActiveModel::Validations when include ActiveModel::SecurePassword
Merge pull request #16024 from aditya-kapoor/include-validations

automatically include ActiveModel::Validations when include ActiveModel::SecurePassword
`DateTime#to_f` now preserves fractional seconds.

Previously this method always returns `.0` in the fractional part. This commit
changes it to preserve the fractional seconds instead.

Fixes #15994.
Merge pull request #16001 from johnpaulashenfelter/jp_fix_datetime_to_f

`DateTime#to_f` now preserves fractional seconds.
Only automatically include validations when enabled

This is a follow up to #16024.
Fix escape_once double-escaping hex-encoded entities

(This is a manual merge of #9102)
The hex escape sequence can be of any length