Save database version in site meta (Multisite)

[spacedmonkey]

Currently there is there a table in multisite called blog_versions. All this table stores is the database version as number and the date updated. With plans to add site meta in #37923 this new table should be used. This has a number of benefits, including functions to CRUD these values in the database. Once this data is in the blogmeta, table, the blog_versions table can be removed all together. If require a SQL view can be used blog_versions from data stored in blogmeta.

[spacedmonkey]

Related: #19755 #37923

[spacedmonkey]

I think we are ready for this in 5.3.

[leogermani]

Looks like this patch needs refresh.

Working on this and on unit tests at the DevDay WCEU2019

[leogermani]

refreshed patch

[leogermani]

Patch

I've refreshed the patch, but looking at it I realized it only updates this info when a db upgrade runs... Isn't it a good idea to add this to the multisite activation somehow to make sure this information is always present? even in a fresh install?

Tests

I was not able to write the tests and would need some help here. Calling wp_upgrade() does not seem to trigger the actual function in the tests environment. Maybe something to do with the pluggable functions... Or maybe Im just missing somehting... Im not sure...

This is what I was working on for tests (draft code)

/**
 * @ticket 41685
 */
public function test_update_db_info_upon_db_update() {
	
	if ( ! is_site_meta_supported() ) {
		$this->markTestSkipped( 'Tests only runs with the blogmeta database table installed' );
	}
	
	global $wp_db_version;
	// force a fake upgrade
	$wp_db_version ++;
	
	wp_upgrade();
	
	$x = get_site_meta( self::$site_id, 'db_version', true );
	
	// check if current site metadata was upgraded...
}

[whyisjake]

Got confirmation over in #19755 for this approach.

[whyisjake]

In 46193:

Networks and Sites: Save database version in site meta (Multisite)

Currently there is there a table in multisite called blog_versions. All this table stores is the database version as number and the date updated. With plans to add site meta in #37923 this new table should be used. This has a number of benefits, including functions to CRUD these values in the database. Once this data is in the blogmeta, table, the blog_versions table can be removed all together. If require a SQL view can be used blog_versions from data stored in blogmeta.

Props spacedmonkey, leogermani.

Fixes #41685. See #19755.

[whyisjake]

In 46194:

Multisite: Remove the redundant blog_versions table.

As part of the Multisite installation process, a blog_versions table is created. This table is never read from (except immediately prior to updating it), it's only ever inserted into or updated. It is not used to determine which blogs need to be upgraded.
This table was introduced in 3.0 when the WPMU schema was merged #11644 and it appears the table has never been used in core and is therefore redundant and may as well be removed.

Props johnbillion, nacin, ryan, johnjamesjacoby, whyisjake.

Fixes #19755. See #41685.

[justinahinon]

Adding needs-dev-notes tag since I drafted a shared note for this and #19755.

​https://make.wordpress.org/core/?p=66113&preview=1&_ppp=ddb7b957d8

[desrosj]

Dev note: ​https://make.wordpress.org/core/2019/10/15/enhancements-to-the-network-sites-screen-in-wordpress-5-3/