Fixed #26718 -- Added system check for existence of the fields specified by ForeignKey.to_field.

1 files changed, 23 insertions, 0 deletions

diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 44e053847a..7caba63c3e 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -463,9 +463,32 @@ class ForeignObject(RelatedField):
 
     def check(self, **kwargs):
         errors = super(ForeignObject, self).check(**kwargs)
+        errors.extend(self._check_to_fields_exist())
         errors.extend(self._check_unique_target())
         return errors
 
+    def _check_to_fields_exist(self):
+        # Skip nonexistent models.
+        if isinstance(self.remote_field.model, six.string_types):
+            return []
+
+        errors = []
+        for to_field in self.to_fields:
+            if to_field:
+                try:
+                    self.remote_field.model._meta.get_field(to_field)
+                except exceptions.FieldDoesNotExist:
+                    errors.append(
+                        checks.Error(
+                            "The to_field '%s' doesn't exist on the related "
+                            "model '%s'."
+                            % (to_field, self.remote_field.model._meta.label),
+                            obj=self,
+                            id='fields.E312',
+                        )
+                    )
+        return errors
+
     def _check_unique_target(self):
         rel_is_string = isinstance(self.remote_field.model, six.string_types)
         if rel_is_string or not self.requires_unique_target: