When that was first implemented in MDL-40672, 10 years ago,

    And the following "activities" exist:

had this error 'handling' applied:

        // Custom exception.

        try {

            $this->datagenerator->create_module($activityname, $data, $cmoptions);

        } catch (coding_exception $e) {

            throw new Exception('\'' . $activityname . '\' activity can not be added using this step,' .

                    ' use the step \'I add a "ACTIVITY_OR_RESOURCE_NAME_STRING" to section "SECTION_NUMBER"\' instead');

        }

In all those years, I have never seen that message until today, and today it was just misleading.

In this case, the real error was

coding_exception: Coding error detected, it must be fixed by a programmer: Invalid availability structure (unknown ->op) in C:\Users\tjh238\workspace\moodle_head\availability\classes\tree.php:152

which came from my attempts to implement this: https://github.com/timhunt/moodle/commit/MDL-79798#diff-cf8371d9243575cafbfb3cd7ef9dd62ee698f139a0c3419ab740185982561385R14.

I think that, in 2023, that catch is not useful advice, so I propose we just remove it.