MDL-58898 oauth: Remove orphaned linked logins

auth/oauth2/classes/api.php

@@ -39,6 +39,16 @@ defined('MOODLE_INTERNAL') || die();
  */
 class api {
 
+    /**
+     * Remove all linked logins that are using issuers that have been deleted.
+     *
+     * @param int $issuerid The issuer id of the issuer to check, or false to check all (defaults to all)
+     * @return boolean
+     */
+    public static function clean_orphaned_linked_logins($issuerid = false) {
+        return linked_login::delete_orphaned($issuerid);
+    }
+
     /**
      * List linked logins
      *

auth/oauth2/classes/linked_login.php

@@ -65,4 +65,26 @@ class linked_login extends persistent {
         );
     }
 
+    /**
+     * Remove all linked logins that are using issuers that have been deleted.
+     *
+     * @param int $issuerid The issuer id of the issuer to check, or false to check all (defaults to all)
+     * @return boolean
+     */
+    public static function delete_orphaned($issuerid = false) {
+        global $DB;
+        // Delete any linked_login entries with a issuerid
+        // which does not exist in the issuer table.
+        // In the left join, the issuer id will be null
+        // where a match linked_login.issuerid is not found.
+        $sql = "DELETE FROM {" . self::TABLE . "}
+                 WHERE issuerid NOT IN (SELECT id FROM {" . \core\oauth2\issuer::TABLE . "})";
+        $params = [];
+        if (!empty($issuerid)) {
+            $sql .= ' AND issuerid = ?';
+            $params['issuerid'] = $issuerid;
+        }
+        return $DB->execute($sql, $params);
+    }
+
 }

auth/oauth2/linkedlogins.php

@@ -79,6 +79,7 @@ $linkedlogin = null;
 echo $OUTPUT->header();
 echo $OUTPUT->heading(get_string('linkedlogins', 'auth_oauth2'));
 echo $OUTPUT->doc_link('Linked_Logins', get_string('linkedloginshelp', 'auth_oauth2'));
+auth_oauth2\api::clean_orphaned_linked_logins();
 $linkedlogins = auth_oauth2\api::get_linked_logins();
 
 echo $renderer->linked_logins_table($linkedlogins);