I use Moodle 3.2 as a Tool consumer and use it to open an external Tool provider to do an exercise and get back the grade. The Tool provider uses LTI library from IMS Global (https://github.com/IMSGlobal/LTI-Tool-Provider-Library-PHP). The submission of grade back to Moodle always fail upon the first submission (no matter who the student is), but successful for other submissions afterwards. When it fails I can find some error logs below:
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 89
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 90
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 90
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 91
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 91
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 92
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 92
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 93
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 136
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/locallib.php on line 1689
PHP Notice: Trying to get property of non-object in .../htdocs/moodle/mod/lti/servicelib.php on line 144
Is it that moodle fails to setup something upon the first receipt of grades?
Adrian