Add nice error message with links to skip sql functions update

extension/Source/core/database/DatabaseUpdate.php

@@ -165,10 +165,16 @@ class DatabaseUpdate {
      * @throws UserFormException
      */
     private function updateSqlFunctions($oldFunctionsHash) {
-        if ('no' === $oldFunctionsHash) {
+        if (ACTION_FUNCTION_UPDATE_NEVER === $oldFunctionsHash) {
             return null;
         }
 
+        if ($_GET[ACTION_FUNCTION_UPDATE] === ACTION_FUNCTION_UPDATE_NEXT_UPDATE) {
+            return ACTION_FUNCTION_UPDATE_NOT_PERFORMED;
+        } elseif ($_GET[ACTION_FUNCTION_UPDATE] === ACTION_FUNCTION_UPDATE_NEVER) {
+            return ACTION_FUNCTION_UPDATE_NEVER;
+        }
+
         $functionsSql = file_get_contents(__DIR__ . '/../../sql/functions.sql');
         $functionsHash = hash('md5', $functionsSql);
 
@@ -193,11 +199,17 @@ class DatabaseUpdate {
             return $functionsHash;
         } else {
             $errorMsg[ERROR_MESSAGE_TO_USER] = 'Error while updating qfq.';
-            $errorMsg[ERROR_MESSAGE_TO_DEVELOPER] = "Error while updating qfq: " .
-                "Could not properly execute the file 'functions.sql' on the QFQ MYSQL database. " .
-                "Please do so manually or set the parameter 'functionsHash' in the table comments of the table" .
-                " 'Form' to 'no' i.e. 'Version=x.y.z&functionHash=no' to disable updating of the qfq mysql functions." .
-                " You may also try giving the mysql user the 'SUPER' privilege temporarily.";
+            $errorMsg[ERROR_MESSAGE_TO_DEVELOPER] =
+                "Failed to play functions.sql, probably not enough permissions for the qfq mysql user. " .
+                "Possible solutions: <ul>" .
+                '<li>Grant Super privilages to qfq mysql user temporarily.</li>' .
+                '<li>Play the following file manually on the database: ' .
+                '<a href="http://webwork16.math.uzh.ch/megger/qfq/typo3conf/ext/qfq/Source/sql/functions.sql">typo3conf/ext/qfq/Source/sql/functions.sql</a></li>' .
+                '<li><a href="?' . http_build_query(array_merge($_GET, array(ACTION_FUNCTION_UPDATE=>ACTION_FUNCTION_UPDATE_NEXT_UPDATE))) . '">Click here</a> to skip the sql functions update until next qfq release update</li>' .
+                '<li><a href="?' . http_build_query(array_merge($_GET, array(ACTION_FUNCTION_UPDATE=>ACTION_FUNCTION_UPDATE_NEVER))) . '">Click here</a> to skip the sql functions update forever</li>' .
+                '</ul>' .
+                "To enable the sql functions update again you can delete the parameter 'functionsHash' in the table comments of the table 'Form'.";
+            $errorMsg[ERROR_MESSAGE_TO_DEVELOPER_SANITIZE] = false;
             throw new DbException(json_encode($errorMsg), ERROR_PLAY_SQL_FILE);
         }
     }