Upgrade/Install: Reduce number of DB queries populating roles.

Reduces the number of database queries made when populating roles during install/multisite site creation by 344 (347 queries down to 3).

`populate_roles()` has been modified to prevent an individual database query each time a role or capability is added to the `WP_Roles` object. Instead the roles option, `{$wpdb->prefix}user_roles` is updated once at the end of the function call.

Introduces a test to ensure that updating the roles option via `WP_Roles` and updating the option in the manner now used by `populate_roles()` results in the same capabilities been applied to a role.

Props fliespl, johnjamesjacoby, ocean90, realloc, rishabhwp, sainathpoojary, sirlouen, spacedmonkey, swissspidy.
Fixes #37687.


Built from https://develop.svn.wordpress.org/trunk@60614


git-svn-id: http://core.svn.wordpress.org/trunk@59950 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/schema.php

@@ -713,6 +713,13 @@ function populate_options( array $options = array() ) {
  * @since 2.0.0
  */
 function populate_roles() {
+	$wp_roles = wp_roles();
+
+	// Disable role updates to the database while populating roles.
+	$original_use_db  = $wp_roles->use_db;
+	$wp_roles->use_db = false;
+
+	// Populate roles
 	populate_roles_160();
 	populate_roles_210();
 	populate_roles_230();
@@ -721,6 +728,14 @@ function populate_roles() {
 	populate_roles_270();
 	populate_roles_280();
 	populate_roles_300();
+
+	// Save the updated roles to the database.
+	if ( $original_use_db ) {
+		update_option( $wp_roles->role_key, $wp_roles->roles, true );
+	}
+
+	// Restore original value for writing to database.
+	$wp_roles->use_db = $original_use_db;
 }
 
 /**

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.9-alpha-60613';
+$wp_version = '6.9-alpha-60614';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.