add migration to fix letter grade set by 0033

courses/migrations/0036_update_letter_grades_for_dedp.py

@@ -0,0 +1,60 @@
+# Generated by Django 3.2.18 on 2023-06-30 20:33
+
+import datetime
+
+import pytz
+from django.db import migrations
+
+from courses.models import Program
+
+
+def convert_to_letter(grade):
+    """Convert a decimal number to letter grade"""
+    if grade >= 0.825:
+        return "A"
+    elif grade >= 0.65:
+        return "B"
+    elif grade >= 0.55:
+        return "C"
+    elif grade >= 0.50:
+        return "D"
+    else:
+        return "F"
+
+
+def populate_letter_grade(apps, schema_editor):
+    """Fix the letter grade for the DEDP courses prior to 3T2022
+    that was set by 0033_populate_letter_grades"""
+    CourseRunGrade = apps.get_model("courses", "CourseRunGrade")
+    Course = apps.get_model("courses", "Course")
+
+    dedp_program = Program.objects.filter(readable_id="program-v1:MITx+DEDP").first()
+
+    if dedp_program is not None:
+        dedp_course_ids = [course[0].id for course in dedp_program.courses]
+        # Good Economics for Hard Times need to be added
+        dedp_course_ids.append(
+            Course.objects.filter(readable_id="course-v1:MITxT+14.009x").first()
+        )
+    else:
+        dedp_course_ids = []
+
+    grades = CourseRunGrade.objects.filter(
+        passed=True,
+        set_by_admin=True,
+        course_run__course_id__in=dedp_course_ids,
+        course_run__start_date__lt=datetime.datetime(2022, 9, 1, tzinfo=pytz.UTC),
+    )
+    for grade in grades:
+        grade.letter_grade = convert_to_letter(grade.grade)
+        grade.save()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("courses", "0035_merge_related_name_and_backfill_enrollments"),
+    ]
+
+    operations = [
+        migrations.RunPython(populate_letter_grade, migrations.RunPython.noop),
+    ]