fix migration to remove out of date index

* reorder index fields

lms/djangoapps/courseware/grades.py

@@ -76,7 +76,7 @@ def grade(student, request, course, student_module_cache=None):
                 # TODO: We may be able to speed this up by only getting a list of children IDs from section_module
                 # Then, we may not need to instatiate any problems if they are already in the database
                 for module in yield_module_descendents(section_module):
-                    (correct, total) = get_score(student, module, student_module_cache)
+                    (correct, total) = get_score(course.id, student, module, student_module_cache)
                     if correct is None and total is None:
                         continue
 
@@ -171,7 +171,9 @@ def progress_summary(student, course, grader, student_module_cache):
             graded = s.metadata.get('graded', False)
             scores = []
             for module in yield_module_descendents(s):
-                (correct, total) = get_score(student, module, student_module_cache)
+                # course is a module, not a descriptor...
+                course_id = course.descriptor.id
+                (correct, total) = get_score(course_id, student, module, student_module_cache)
                 if correct is None and total is None:
                     continue
 
@@ -200,7 +202,7 @@ def progress_summary(student, course, grader, student_module_cache):
     return chapters
 
 
-def get_score(user, problem, student_module_cache):
+def get_score(course_id, user, problem, student_module_cache):
     """
     Return the score for a user on a problem, as a tuple (correct, total).
 
@@ -215,7 +217,7 @@ def get_score(user, problem, student_module_cache):
     correct = 0.0
 
     # If the ID is not in the cache, add the item
-    instance_module = get_instance_module(user, problem, student_module_cache)
+    instance_module = get_instance_module(course_id, user, problem, student_module_cache)
     # instance_module = student_module_cache.lookup(problem.category, problem.id)
     # if instance_module is None:
     #     instance_module = StudentModule(module_type=problem.category,

lms/djangoapps/courseware/migrations/0003_done_grade_cache.py

@@ -9,6 +9,8 @@ class Migration(SchemaMigration):
 
     def forwards(self, orm):
 
+        # NOTE (vshnayder): This constraint has the wrong field order, so it doesn't actually
+        # do anything.  Migration 0004 actually removes this index.
         # Removing unique constraint on 'StudentModule', fields ['module_id', 'module_type', 'student']
         db.delete_unique('courseware_studentmodule', ['module_id', 'module_type', 'student_id'])
 

lms/djangoapps/courseware/migrations/0004_add_field_studentmodule_course_id.py

@@ -16,13 +16,17 @@ class Migration(SchemaMigration):
         # Removing unique constraint on 'StudentModule', fields ['module_id', 'student']
         db.delete_unique('courseware_studentmodule', ['module_id', 'student_id'])
 
+        # NOTE: manually remove this constaint (from 0001)--0003 tries, but fails.
+        # Removing unique constraint on 'StudentModule', fields ['module_id', 'module_type', 'student']
+        db.delete_unique('courseware_studentmodule', ['student_id', 'module_id', 'module_type'])
+
         # Adding unique constraint on 'StudentModule', fields ['course_id', 'module_state_key', 'student']
-        db.create_unique('courseware_studentmodule', ['course_id', 'module_id', 'student_id'])
+        db.create_unique('courseware_studentmodule', ['student_id', 'module_id', 'course_id'])
 
 
     def backwards(self, orm):
-        # Removing unique constraint on 'StudentModule', fields ['course_id', 'module_state_key', 'student']
-        db.delete_unique('courseware_studentmodule', ['course_id', 'module_id', 'student_id'])
+        # Removing unique constraint on 'StudentModule', fields ['studnet_id', 'module_state_key', 'course_id']
+        db.delete_unique('courseware_studentmodule', ['student_id', 'module_id', 'course_id'])
 
         # Deleting field 'StudentModule.course_id'
         db.delete_column('courseware_studentmodule', 'course_id')
@@ -30,6 +34,9 @@ class Migration(SchemaMigration):
         # Adding unique constraint on 'StudentModule', fields ['module_id', 'student']
         db.create_unique('courseware_studentmodule', ['module_id', 'student_id'])
 
+        # Adding unique constraint on 'StudentModule', fields ['module_id', 'module_type', 'student']
+        db.create_unique('courseware_studentmodule', ['student_id', 'module_id', 'module_type'])
+
 
     models = {
         'auth.group': {

lms/djangoapps/courseware/models.py

@@ -43,7 +43,7 @@ class StudentModule(models.Model):
     course_id = models.CharField(max_length=255, db_index=True)
 
     class Meta:
-        unique_together = (('course_id', 'student', 'module_state_key'),)
+        unique_together = (('student', 'module_state_key', 'course_id'),)
 
     ## Internal state of the object
     state = models.TextField(null=True, blank=True)