IPv6 support for multisite wp_registration_log

[dd32]

Trac ticket: https://core.trac.wordpress.org/ticket/63986#ticket

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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Props dd32, wildworks, tobiasbg, georgestephanis, motylanogha.

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[github-actions]

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[wppoland]

Since the description notes the change is "untested and only validated on a visual review", here's a regression test for the core behavior — an IPv6 REMOTE_ADDR being stored intact by wpmu_log_new_registrations(). It passes on this branch and fails on trunk, where the old /[^0-9., ]/ mask strips the colons and hex digits (e.g. 2001:0db8:…:7334 becomes 200108853…07334).

Goes in tests/phpunit/tests/multisite/wpmuLogNewRegistrations.php:

	/**
	 * Ensures an IPv6 remote address is preserved when logging a registration.
	 *
	 * @ticket 63986
	 */
	public function test_wpmu_log_new_registrations_preserves_ipv6_address() {
		global $wpdb;

		$ipv6                   = '2001:0db8:85a3:0000:0000:8a2e:0370:7334';
		$original_remote_addr   = isset( $_SERVER['REMOTE_ADDR'] ) ? $_SERVER['REMOTE_ADDR'] : null;
		$_SERVER['REMOTE_ADDR'] = $ipv6;

		try {
			wpmu_log_new_registrations( 1, 1 );

			$logged_ip = $wpdb->get_var( "SELECT IP FROM {$wpdb->registration_log} WHERE blog_id = 1 ORDER BY ID DESC LIMIT 1" );
		} finally {
			if ( null === $original_remote_addr ) {
				unset( $_SERVER['REMOTE_ADDR'] );
			} else {
				$_SERVER['REMOTE_ADDR'] = $original_remote_addr;
			}
		}

		$this->assertSame(
			$ipv6,
			$logged_ip,
			'The IPv6 remote address was not stored intact in the registration log.'
		);
	}

Run with -c tests/phpunit/multisite.xml. One note while here: the sanitizing regex only allows lowercase hex (a-f), so an uppercase-hex IPv6 literal would still be partly stripped — worth considering a-fA-F if that's a concern. Happy to push the test as a commit.

[Copilot]

Pull request overview

Adds IPv6 compatibility for multisite registration logging by expanding the stored IP format and updating the multisite schema/upgrade path accordingly.

Changes:

• Allow IPv6 characters when storing $_SERVER['REMOTE_ADDR'] into wp_registration_log.
• Expand registration_log.IP column width from varchar(30) to varchar(39) in the multisite schema.
• Add a multisite upgrade step intended to widen the existing registration_log.IP column.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/wp-includes/ms-functions.php	Updates IP sanitization for wpmu_log_new_registrations() to better accommodate IPv6.
src/wp-admin/includes/upgrade.php	Adds a multisite schema upgrade step to widen the registration_log.IP column (version-gated).
src/wp-admin/includes/schema.php	Updates the multisite schema definition so new installs create registration_log.IP as varchar(39).

Comments suppressed due to low confidence (1)

src/wp-admin/includes/upgrade.php:3775

• Indentation of this query line is inconsistent with the surrounding block (extra tab), which makes the upgrade code harder to read and violates the file’s existing formatting.

				$wpdb->query( "ALTER TABLE $wpdb->registration_log MODIFY IP varchar(39) NOT NULL default ''" );

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