Fix crash when EmbeddedModelArrayField's embedded_model arg is a string

Author: timgraham

django_mongodb_backend/fields/embedded_model_array.py

@@ -1,4 +1,5 @@
 from django.db.models import Field
+from django.db.models.fields.related import lazy_related_operation
 
 from .. import forms
 from . import EmbeddedModelField
@@ -12,6 +13,17 @@ def __init__(self, embedded_model, **kwargs):
         super().__init__(EmbeddedModelField(embedded_model), **kwargs)
         self.embedded_model = embedded_model
 
+    def contribute_to_class(self, cls, name, private_only=False, **kwargs):
+        super().contribute_to_class(cls, name, private_only=private_only, **kwargs)
+
+        if not cls._meta.abstract:
+            # If the embedded_model argument is a string, resolve it to the
+            # actual model class.
+            def _resolve_lookup(_, resolved_model):
+                self.embedded_model = resolved_model
+
+            lazy_related_operation(_resolve_lookup, cls, self.embedded_model)
+
     def deconstruct(self):
         name, path, args, kwargs = super().deconstruct()
         if path == "django_mongodb_backend.fields.embedded_model_array.EmbeddedModelArrayField":

tests/model_fields_/models.py

@@ -151,17 +151,17 @@ def __str__(self):
 
 
 # EmbeddedModelArrayField
-class Review(EmbeddedModel):
+class Movie(models.Model):
     title = models.CharField(max_length=255)
-    rating = models.DecimalField(max_digits=6, decimal_places=1)
+    reviews = EmbeddedModelArrayField("Review", null=True)
 
     def __str__(self):
         return self.title
 
 
-class Movie(models.Model):
+class Review(EmbeddedModel):
     title = models.CharField(max_length=255)
-    reviews = EmbeddedModelArrayField(Review, null=True)
+    rating = models.DecimalField(max_digits=6, decimal_places=1)
 
     def __str__(self):
         return self.title