fix: delete perm on user/group/team deletion

This is done manually using signal because we do not use a foreign key
so we do not have automatically cascade deletion.

permissions/signals.py

@@ -0,0 +1,50 @@
+from django.db.models.signals import pre_delete
+from django.dispatch import receiver
+
+from accounts.models import *
+from permissions.models import *
+
+
+"""
+As permissions objects do not use a foreign key but instead an integer field
+on the foreign object id, we can rely on database cascade deletion to delete
+outaded permissions and we have to do it our-self.
+"""
+
+@receiver(pre_delete, sender=User, dispatch_uid="clean_user_perms")
+def clean_user_perms(sender, instance, **kwargs):
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_USER)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_USER)
+    perms.delete()
+
+
+@receiver(pre_delete, sender=Group, dispatch_uid="clean_group_perms")
+def clean_group_perms(sender, instance, **kwargs):
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_GROUP)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_GROUP)
+    perms.delete()
+
+
+@receiver(pre_delete, sender=Team, dispatch_uid="clean_team_perms")
+def clean_team_perms(sender, instance, **kwargs):
+    print(instance)
+    print(instance.id)
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_TEAM)
+    print(perms)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_TEAM)
+    perms.delete()