fix QuerySet.update() with related model instance

Author: timgraham

.github/workflows/test-python.yml

@@ -74,7 +74,9 @@ jobs:
           model_fields.test_datetimefield
           model_fields.test_decimalfield
           model_fields.test_charfield
+          model_fields.test_floatfield
           model_fields.test_textfield
+          model_fields.test_uuid.TestAsPrimaryKey.test_update_with_related_model_instance
           or_lookups
 
   docs:

django_mongodb/compiler.py

@@ -223,6 +223,15 @@ def execute_sql(self, result_type):
         self.pre_sql_setup()
         values = []
         for field, _, value in self.query.values:
+            if hasattr(value, "prepare_database_save"):
+                if field.remote_field:
+                    value = value.prepare_database_save(field)
+                else:
+                    raise TypeError(
+                        f"Tried to update field {field} with a model "
+                        f"instance, {value!r}. Use a value compatible with "
+                        f"{field.__class__.__name__}."
+                    )
             prepared = field.get_db_prep_save(value, connection=self.connection)
             values.append((field, prepared))
         return self.update(values)

pyproject.toml

@@ -104,6 +104,7 @@ ignore = [
   "ARG002", # Unused method argument:
   "S101",   # Use of `assert` detected
   "RUF012", # Mutable class attributes should be annotated with `typing.ClassVar`
+  "PLW2901", # `for` loop variable `value` overwritten by assignment target
 ]
 unfixable = []
 exclude = []