Fix user_id type mismatch when user claim is not pk

Regarding changes made at https://github.com/jazzband/djangorestframework-simplejwt/pull/806/files

We're using a USER_ID_CLAIM that is neither the primary key field nor is it the
same type as the primary key, and these previous changes fail at this point
when attempting to create an OutstandingToken, because it assumes that the ID
pulled out of the token claims is usable as the database key for a user.

So to mitigate this gets the user from the database using the USER_ID_FIELD
setting and uses that in the get_or_create call.

rest_framework_simplejwt/tokens.py

@@ -3,6 +3,7 @@
 from uuid import uuid4
 
 from django.conf import settings
+from django.contrib.auth import get_user_model
 from django.contrib.auth.models import AbstractBaseUser
 from django.utils.module_loading import import_string
 from django.utils.translation import gettext_lazy as _
@@ -266,12 +267,17 @@ def blacklist(self) -> BlacklistedToken:
             jti = self.payload[api_settings.JTI_CLAIM]
             exp = self.payload["exp"]
             user_id = self.payload.get(api_settings.USER_ID_CLAIM)
+            User = get_user_model()
+            try:
+                user = User.objects.get(**{api_settings.USER_ID_FIELD: user_id})
+            except User.DoesNotExist:
+                user = None
 
             # Ensure outstanding token exists with given jti
             token, _ = OutstandingToken.objects.get_or_create(
                 jti=jti,
                 defaults={
-                    "user_id": user_id,
+                    "user": user,
                     "created_at": self.current_time,
                     "token": str(self),
                     "expires_at": datetime_from_epoch(exp),

tests/test_token_blacklist.py

@@ -6,7 +6,6 @@
 from django.db.models import BigAutoField
 from django.test import TestCase
 from django.utils import timezone
-
 from rest_framework_simplejwt.exceptions import TokenError
 from rest_framework_simplejwt.serializers import TokenVerifySerializer
 from rest_framework_simplejwt.settings import api_settings
@@ -160,6 +159,26 @@ def test_outstanding_token_and_blacklisted_token_user(self):
         outstanding_token = OutstandingToken.objects.get(token=token)
         self.assertEqual(outstanding_token.user, self.user)
 
+    @override_api_settings(USER_ID_FIELD="email", USER_ID_CLAIM="email")
+    def test_outstanding_token_and_blacklisted_token_created_at_with_modified_user_id_field(
+        self,
+    ):
+        token = RefreshToken.for_user(self.user)
+
+        token.blacklist()
+        outstanding_token = OutstandingToken.objects.get(token=token)
+        self.assertEqual(outstanding_token.created_at, token.current_time)
+
+    @override_api_settings(USER_ID_FIELD="email", USER_ID_CLAIM="email")
+    def test_outstanding_token_and_blacklisted_token_user_with_modifed_user_id_field(
+        self,
+    ):
+        token = RefreshToken.for_user(self.user)
+
+        token.blacklist()
+        outstanding_token = OutstandingToken.objects.get(token=token)
+        self.assertEqual(outstanding_token.user, self.user)
+
 
 class TestTokenBlacklistFlushExpiredTokens(TestCase):
     def setUp(self):