Merge pull request #18097 from edx/sstudent/EDUCATOR-2690

make password history retirable

common/djangoapps/student/models.py

@@ -29,7 +29,7 @@ from django.contrib.auth.models import User
 from django.contrib.auth.signals import user_logged_in, user_logged_out
 from django.core.cache import cache
 from django.core.exceptions import MultipleObjectsReturned, ObjectDoesNotExist
-from django.db import IntegrityError, models
+from django.db import IntegrityError, models, transaction
 from django.db.models import Count, Q
 from django.db.models.signals import post_save, pre_save
 from django.dispatch import receiver
@@ -900,6 +900,20 @@ class PasswordHistory(models.Model):
 
         return True
 
+    @classmethod
+    def retire_user(cls, user_id):
+        """
+        Updates the password in all rows corresponding to a user
+        to an empty string as part of removing PII for user retirement.
+        """
+        changed_password = False
+        with transaction.atomic():
+            for row, _ in cls.objects.filter(user_id=user_id):
+                changed_password = True
+                row.password = ""
+
+        return changed_password
+
 
 class LoginFailures(models.Model):
     """

common/djangoapps/student/tests/test_password_history.py

@@ -203,3 +203,20 @@ class TestPasswordHistory(TestCase):
         student = self._user_factory_with_history()
 
         self.assertFalse(PasswordHistory.is_password_reset_too_soon(student))
+
+    def test_retirement(self):
+        """
+        Verify that the user's password history contains no actual
+        passwords after retirement is called.
+        """
+        user = self._user_factory_with_history()
+
+        # create multiple rows in the password history table
+        self._change_password(user, "different")
+        self._change_password(user, "differentagain")
+        for row in PasswordHistory.objects.filter(user_id=user.id):
+            self.assertFalse(row.password == "")
+
+        PasswordHistory.retire_user(user.id)
+        for row in PasswordHistory.objects.filter(user_id=user.id):
+            self.assertEqual(row.password, "")