- Turn on foreign key constraint checking in the tests

- Change all ForeignKeyField's that refer to users to use our custom class, and mark those that allow robots
- Change robot delete to only execute the subset of queries necessary to actually delete robots

data/model/legacy.py

@@ -14,7 +14,7 @@ from data.database import (User, Repository, Image, AccessToken, Role, Repositor
                            ExternalNotificationEvent, ExternalNotificationMethod,
                            RepositoryNotification, RepositoryAuthorizedEmail, TeamMemberInvite,
                            DerivedImageStorage, ImageStorageTransformation, random_string_generator,
-                           db, BUILD_PHASE)
+                           db, BUILD_PHASE, QuayUserField)
 from peewee import JOIN_LEFT_OUTER, fn
 from util.validation import (validate_username, validate_email, validate_password,
                              INVALID_PASSWORD_MESSAGE)
@@ -287,7 +287,16 @@ def regenerate_robot_token(robot_shortname, parent):
 def delete_robot(robot_username):
   try:
     robot = User.get(username=robot_username, robot=True)
-    robot.delete_instance(recursive=True, delete_nullable=True)
+
+    # For all the model dependencies, only delete those that allow robots.
+    for query, fk in robot.dependencies(search_nullable=True):
+      if isinstance(fk, QuayUserField) and fk.allows_robots:
+        model = fk.model_class
+        model.delete().where(query).execute()
+
+    # Delete the robot itself.
+    robot.delete_instance(recursive=False)
+
   except User.DoesNotExist:
     raise InvalidRobotException('Could not find robot with username: %s' %
                                 robot_username)