From 81c9dc54f4e0f225f2afcac27d9b4c406f64a553 Mon Sep 17 00:00:00 2001
From: Dan Palmer <dan@danpalmer.me>
Date: Thu, 19 Jul 2018 11:48:39 +0100
Subject: [PATCH] Support converters for custom fields with choices

---
 graphene_django/converter.py | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/graphene_django/converter.py b/graphene_django/converter.py
index da73ede..3bc28ea 100644
--- a/graphene_django/converter.py
+++ b/graphene_django/converter.py
@@ -38,13 +38,25 @@ def get_choices(choices):
             yield name, value, description
 
 
+class UnknownDjangoFieldException(Exception):
+    pass
+
+
 def convert_django_field_with_choices(field, registry=None):
     if registry is not None:
         converted = registry.get_converted_field(field)
         if converted:
             return converted
-    choices = getattr(field, 'choices', None)
-    if choices:
+
+    try:
+        converted = convert_django_field(field, registry)
+    except UnknownDjangoFieldException:
+        choices = getattr(field, 'choices', None)
+        if not choices:
+            # We don't have a converter and can't convert automatically to an
+            # enum.
+            raise
+
         meta = field.model._meta
         name = to_camel_case('{}_{}'.format(meta.object_name, field.name))
         choices = list(get_choices(choices))
@@ -59,8 +71,7 @@ def convert_django_field_with_choices(field, registry=None):
 
         enum = Enum(name, list(named_choices), type=EnumWithDescriptionsType)
         converted = enum(description=field.help_text, required=not field.null)
-    else:
-        converted = convert_django_field(field, registry)
+
     if registry is not None:
         registry.register_converted_field(field, converted)
     return converted
@@ -68,7 +79,7 @@ def convert_django_field_with_choices(field, registry=None):
 
 @singledispatch
 def convert_django_field(field, registry=None):
-    raise Exception(
+    raise UnknownDjangoFieldException(
         "Don't know how to convert the Django field %s (%s)" %
         (field, field.__class__))