add suggestions lookups

Author: WaVEV

django_mongodb_backend/fields/embedded_model.py

@@ -1,3 +1,5 @@
+import difflib
+
 from django.core import checks
 from django.core.exceptions import FieldDoesNotExist
 from django.db import models
@@ -149,9 +151,15 @@ def get_transform(self, name):
             result = KeyTransformFactory(name, new_field)
         else:
             if self.ref_field.get_transform(name) is None:
+                suggested_lookups = difflib.get_close_matches(name, self.ref_field.get_lookups())
+                if suggested_lookups:
+                    suggested_lookups = " or ".join(suggested_lookups)
+                    suggestion = f", perhaps you meant {suggested_lookups}?"
+                else:
+                    suggestion = "."
                 raise FieldDoesNotExist(
                     f"Unsupported lookup '{name}' for "
-                    f"{self.ref_field.__class__.__name__} '{self.ref_field.name}'"
+                    f"{self.ref_field.__class__.__name__} '{self.ref_field.name}'{suggestion}"
                 )
             result = KeyTransformFactory(name, self.ref_field)
         return result

tests/model_fields_/test_embedded_model.py

@@ -119,6 +119,24 @@ def test_not_exists_in_embedded(self):
         with self.assertRaisesMessage(FieldDoesNotExist, msg):
             Book.objects.filter(author__address__floor="NYC")
 
+    def test_unsupported_lookups(self):
+        msg = (
+            "Unsupported lookup '{lookup}' for CharField 'name', "
+            "perhaps you meant {suggested_lookups}"
+        )
+        with self.assertRaisesMessage(
+            FieldDoesNotExist, msg.format(lookup="exactly", suggested_lookups="exact or iexact")
+        ):
+            Book.objects.filter(author__name__exactly="NYC").all()
+        with self.assertRaisesMessage(
+            FieldDoesNotExist, msg.format(lookup="gti", suggested_lookups="gt or gte")
+        ):
+            Book.objects.filter(author__name__gti="NYC").all()
+        with self.assertRaisesMessage(
+            FieldDoesNotExist, msg.format(lookup="is_null", suggested_lookups="isnull")
+        ):
+            Book.objects.filter(author__name__is_null="NYC").all()
+
 
 @isolate_apps("model_fields_")
 class CheckTests(SimpleTestCase):