Merge pull request #1657 from MITx/fix/brian/regrade-partial

add management command to regrade partial-credit problems affected by ge...

lms/djangoapps/courseware/management/commands/regrade_partial.py

+'''
+This is a one-off command aimed at fixing a temporary problem encountered where partial credit was awarded for
+code problems, but the resulting score (or grade) was mistakenly set to zero because of a bug in
+CorrectMap.get_npoints().
+'''
+
+import json
+import logging
+from optparse import make_option
+
+from django.core.management.base import BaseCommand
+
+from courseware.models import StudentModule
+from capa.correctmap import CorrectMap
+
+LOG = logging.getLogger(__name__)
+
+
+class Command(BaseCommand):
+    '''
+    The fix here is to recalculate the score/grade based on the partial credit.
+    To narrow down the set of problems that might need fixing, the StudentModule
+    objects to be checked is filtered down to those:
+
+        created < '2013-03-08 15:45:00' (the problem must have been answered before the fix was installed,
+                                         on Prod and Edge)
+        modified > '2013-03-07 20:18:00' (the problem must have been visited after the bug was introduced)
+        state like '%"npoints": 0.%' (the problem must have some form of partial credit).
+    '''
+
+    num_visited = 0
+    num_changed = 0
+
+    option_list = BaseCommand.option_list + (
+        make_option('--save',
+                    action='store_true',
+                    dest='save_changes',
+                    default=False,
+                    help='Persist the changes that were encountered.  If not set, no changes are saved.'), )
+
+    def fix_studentmodules(self, save_changes):
+        '''Identify the list of StudentModule objects that might need fixing, and then fix each one'''
+        modules = StudentModule.objects.filter(modified__gt='2013-03-07 20:18:00',
+                                               created__lt='2013-03-08 15:45:00',
+                                               state__contains='"npoints": 0.')
+
+        for module in modules:
+            self.fix_studentmodule_grade(module, save_changes)
+
+    def fix_studentmodule_grade(self, module, save_changes):
+        ''' Fix the grade assigned to a StudentModule'''
+        module_state = module.state
+        if module_state is None:
+            # not likely, since we filter on it.  But in general...
+            LOG.info("No state found for {type} module {id} for student {student} in course {course_id}"
+                     .format(type=module.module_type, id=module.module_state_key,
+                             student=module.student.username, course_id=module.course_id))
+            return
+
+        state_dict = json.loads(module_state)
+        self.num_visited += 1
+
+        # LoncapaProblem.get_score() checks student_answers -- if there are none, we will return a grade of 0
+        # Check that this is the case, but do so sooner, before we do any of the other grading work.
+        student_answers = state_dict['student_answers']
+        if (not student_answers) or len(student_answers) == 0:
+            # we should not have a grade here:
+            if module.grade != 0:
+                LOG.error("No answer found but grade {grade} exists for {type} module {id} for student {student} "
+                          "in course {course_id}".format(grade=module.grade,
+                                                         type=module.module_type, id=module.module_state_key,
+                                                         student=module.student.username, course_id=module.course_id))
+            else:
+                LOG.debug("No answer and no grade found for {type} module {id} for student {student} "
+                          "in course {course_id}".format(grade=module.grade,
+                                                         type=module.module_type, id=module.module_state_key,
+                                                         student=module.student.username, course_id=module.course_id))
+            return
+
+        # load into a CorrectMap, as done in LoncapaProblem.__init__():
+        correct_map = CorrectMap()
+        if 'correct_map' in state_dict:
+            correct_map.set_dict(state_dict['correct_map'])
+
+        # calculate score the way LoncapaProblem.get_score() works, by deferring to
+        # CorrectMap's get_npoints implementation.
+        correct = 0
+        for key in correct_map:
+            correct += correct_map.get_npoints(key)
+
+        if module.grade == correct:
+            # nothing to change
+            LOG.debug("Grade matches for {type} module {id} for student {student} in course {course_id}"
+                      .format(type=module.module_type, id=module.module_state_key,
+                              student=module.student.username, course_id=module.course_id))
+        elif save_changes:
+            # make the change
+            LOG.info("Grade changing from {0} to {1} for {type} module {id} for student {student} "
+                     "in course {course_id}".format(module.grade, correct,
+                                                    type=module.module_type, id=module.module_state_key,
+                                                    student=module.student.username, course_id=module.course_id))
+            module.grade = correct
+            module.save()
+            self.num_changed += 1
+        else:
+            # don't make the change, but log that the change would be made
+            LOG.info("Grade would change from {0} to {1} for {type} module {id} for student {student} "
+                     "in course {course_id}".format(module.grade, correct,
+                                                    type=module.module_type, id=module.module_state_key,
+                                                    student=module.student.username, course_id=module.course_id))
+            self.num_changed += 1
+
+    def handle(self, **options):
+        '''Handle management command request'''
+
+        save_changes = options['save_changes']
+
+        LOG.info("Starting run: save_changes = {0}".format(save_changes))
+
+        self.fix_studentmodules(save_changes)
+
+        LOG.info("Finished run:  updating {0} of {1} modules".format(self.num_changed, self.num_visited))