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  1. Moodle
  2. MDL-50894

Cron Error: division by zero warning in lib/conditionlib.php

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    • MOODLE_28_STABLE, MOODLE_29_STABLE, MOODLE_30_STABLE
    • MOODLE_28_STABLE, MOODLE_29_STABLE
    • MDL-50894_master
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      Steps to reproduce it using the Interface (with the patch not applied/reverted):

      1: Enable availability (admin/settings.php?section=optionalsubsystems)
      2: For a specific quiz/assignment, make the row grade min/max values equal to force a division by zero and have its finalgrade set.
      3: Set up conditional availability in (course/modedit.php) (example, have the assignment in step #2 be dependent on the completion of another assignment/quiz)
      4: Clear cache
      5. Login as an enrolled student to the course and visit the course page to induce the error.

      After the above 5 steps, if you check the log file, you should see the bellow message.

      PHP Warning: Division by zero in lib/conditionlib.php on line 1221

      Once the warning is reproducible consistently for new enrolled users...

      6: Apply the patch, enrol some new users and log in with them, visiting the course page.
      7: There shouldn't be more PHP Warnings at all.

      Show
      Steps to reproduce it using the Interface (with the patch not applied/reverted): 1: Enable availability (admin/settings.php?section=optionalsubsystems) 2: For a specific quiz/assignment, make the row grade min/max values equal to force a division by zero and have its finalgrade set. 3: Set up conditional availability in (course/modedit.php) (example, have the assignment in step #2 be dependent on the completion of another assignment/quiz) 4: Clear cache 5. Login as an enrolled student to the course and visit the course page to induce the error. After the above 5 steps, if you check the log file, you should see the bellow message. PHP Warning: Division by zero in lib/conditionlib.php on line 1221 Once the warning is reproducible consistently for new enrolled users... 6: Apply the patch, enrol some new users and log in with them, visiting the course page. 7: There shouldn't be more PHP Warnings at all.

    Description

      When you run a cron a

      $ php admin/cli/cron.php

      The below warning is displayed.

      PHP Warning: Division by zero in lib/conditionlib.php on line 1221

      This error comes from the below division in get_cached_grade_score when it runs across grades with zero rawgrademax value. There are grade items with grademax set to zero. This code should handle such grade items without throwing errors.

              foreach ($rs as $record) {
                          $cachedgrades[$record->id] =
                              is_null($record->finalgrade)
                                  // No grade = false
                                  ? false
                                  // Otherwise convert grade to percentage
                                  : (($record->finalgrade - $record->rawgrademin) * 100) /
                                      ($record->rawgrademax - $record->rawgrademin);
      

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              Gedion Gedion
              Gedion Gedion
              Frédéric Massart Frédéric Massart
              Eloy Lafuente (stronk7) Eloy Lafuente (stronk7)
              Jun Pataleta Jun Pataleta
              Sam Marshall, Amaia Anabitarte, Carlos Escobedo, Ferran Recio, Ilya Tregubov, Laurent David, Sara Arjona (@sarjona)
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              1 Vote for this issue
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              5 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:
                14/Sep/15