Fix bug with outdated models

This bug would occur when the database would return
a column that does not exists on the model.

The fix is to not blindly pass all data returned by
the database to the model. We now filter it and make
sure that the field exists on the model.

Author: Photonios

psqlextra/manager.py

@@ -1,4 +1,4 @@
-from typing import List, Dict
+from typing import Dict, List
 
 import django
 from django.conf import settings
@@ -63,7 +63,23 @@ def upsert_and_get(self, conflict_target: List, fields: Dict):
 
         compiler = self._build_upsert_compiler(conflict_target, fields)
         column_data = compiler.execute_sql(return_id=False)
-        return self.model(**column_data)
+
+        # get a list of columns that are officially part of the model
+        model_columns = [
+            field.column
+            for field in self.model._meta.local_concrete_fields
+        ]
+
+        # strip out any columns/fields returned by the db that
+        # are not present in the model
+        model_init_fields = {}
+        for column_name, column_value in column_data.items():
+            if column_name not in model_columns:
+                continue
+
+            model_init_fields[column_name] = column_value
+
+        return self.model(**model_init_fields)
 
     def _build_upsert_compiler(self, conflict_target: List, kwargs):
         """Builds the SQL compiler for a insert/update query.

tests/test_upsert.py

@@ -1,12 +1,12 @@
+import pytest
+from django.core.exceptions import SuspiciousOperation
+from django.db import connection, models
 from django.test import TestCase
 
 from psqlextra import HStoreField
 
 from .fake_model import get_fake_model
-from django.db import models
-import pytest
 
-from django.core.exceptions import SuspiciousOperation
 
 @pytest.mark.django_db
 class UpsertTest(TestCase):
@@ -172,3 +172,33 @@ def test_invalid_conflict_target(self):
                     title='beer'
                 )
             )
+
+    def test_outdated_model(self):
+        """Tests whether upsert_and_get properly handles
+        fields that are in the database but not on the model.
+
+        This happens if somebody manually modified the database
+        to add a column that is not present in the model.
+
+        This should be handled properly by ignoring the column
+        returned by the database.
+        """
+
+        model = get_fake_model({
+            'title': models.CharField(max_length=140, unique=True)
+        })
+
+        # manually create the colum that is not on the model
+        with connection.cursor() as cursor:
+            cursor.execute((
+                'ALTER TABLE {table} '
+                'ADD COLUMN beer character varying(50);'
+            ).format(table=model._meta.db_table))
+
+        # without proper handling, this would fail with a TypeError
+        model.objects.upsert_and_get(
+            conflict_target=['title'],
+            fields=dict(
+                title='beer'
+            )
+        )