Upgrade/Install: Introduce the `wp_installed_email` filter for filtering the contents of the email sent when WordPress is installed, without needing to override the `wp_new_blog_notification()` pluggable function.

Props Dharm1025, nikolam, johnbillion

Fixes #42133

Built from https://develop.svn.wordpress.org/trunk@49048


git-svn-id: http://core.svn.wordpress.org/trunk@48810 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/upgrade.php

@@ -586,17 +586,18 @@ function wp_install_maybe_enable_pretty_permalinks() {
 
 if ( ! function_exists( 'wp_new_blog_notification' ) ) :
 	/**
-	 * Notifies the site admin that the setup is complete.
+	 * Notifies the site admin that the installation of WordPress is complete.
 	 *
-	 * Sends an email with wp_mail to the new administrator that the site setup is complete,
+	 * Sends an email to the new administrator that the installation is complete
 	 * and provides them with a record of their login credentials.
 	 *
 	 * @since 2.1.0
 	 *
 	 * @param string $blog_title Site title.
-	 * @param string $blog_url   Site url.
-	 * @param int    $user_id    User ID.
-	 * @param string $password   User's Password.
+	 * @param string $blog_url   Site URL.
+	 * @param int    $user_id    Administrator's user ID.
+	 * @param string $password   Administrator's password. Note that a placeholder message is
+	 *                           usually passed instead of the actual password.
 	 */
 	function wp_new_blog_notification( $blog_title, $blog_url, $user_id, $password ) {
 		$user      = new WP_User( $user_id );
@@ -629,7 +630,40 @@ https://wordpress.org/
 			$login_url
 		);
 
-		wp_mail( $email, __( 'New WordPress Site' ), $message );
+		$installed_email = array(
+			'to'      => $email,
+			'subject' => __( 'New WordPress Site' ),
+			'message' => $message,
+			'headers' => '',
+		);
+
+		/**
+		 * Filters the contents of the email sent to the site administrator when WordPress is installed.
+		 *
+		 * @since 5.6.0
+		 *
+		 * @param array $installed_email {
+		 *     Used to build wp_mail().
+		 *
+		 *     @type string $to      The email address of the recipient.
+		 *     @type string $subject The subject of the email.
+		 *     @type string $message The content of the email.
+		 *     @type string $headers Headers.
+		 * }
+		 * @param WP_User $user          The site administrator user object.
+		 * @param string  $blog_title    The site title.
+		 * @param string  $blog_url      The site URL.
+		 * @param string  $password      The site administrator's password. Note that a placeholder message
+		 *                               is usually passed instead of the user's actual password.
+		 */
+		$installed_email = apply_filters( 'wp_installed_email', $installed_email, $user, $blog_title, $blog_url, $password );
+
+		wp_mail(
+			$installed_email['to'],
+			$installed_email['subject'],
+			$installed_email['message'],
+			$installed_email['headers']
+		);
 	}
 endif;
 

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-49047';
+$wp_version = '5.6-alpha-49048';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.