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

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

+import json
+import logging
+from optparse import make_option
+
+from django.core.management.base import BaseCommand # , CommandError
+
+from courseware.models import StudentModule
+from capa.correctmap import CorrectMap
+
+#
+# This is 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().
+# 
+# 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:
+#
+#   grade=0.0  (the grade must have been zeroed out)
+#   created < '2013-03-08 05:19:00' (the problem must have been answered before the fix was installed)
+#   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).
+#
+
+log = logging.getLogger(__name__)
+
+class Command(BaseCommand):
+    
+    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):
+        modules = StudentModule.objects.filter(# module_type='problem',
+                                               modified__gt='2013-03-07 20:18:00',
+                                               created__lt='2013-03-08 05:19:00',
+                                               state__contains='"npoints": 0.',
+                                               grade=0.0) 
+        for module in modules:
+            self.fix_studentmodule(module, save_changes)
+            
+    def fix_studentmodule(self, module, save_changes):
+        module_state = module.state
+        if module_state is None:
+            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
+        
+        correct_map = CorrectMap()
+        if 'correct_map' in state_dict:
+            correct_map.set_dict(state_dict['correct_map'])
+    
+        correct = 0
+        for key in correct_map:
+            correct += correct_map.get_npoints(key)
+    
+        if module.grade == correct:
+            log.info("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:
+            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:
+            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):
+        save_changes = 'save_changes' in options and 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))
+