Fix for verbose_field_name (#722)

* Failing test for #716

* Handle case where related_name is None

django_filters/utils.py

@@ -174,7 +174,10 @@ def verbose_field_name(model, field_name):
     names = []
     for part in parts:
         if isinstance(part, ForeignObjectRel):
-            names.append(part.related_name.replace('_', ' '))
+            if part.related_name:
+                names.append(part.related_name.replace('_', ' '))
+            else:
+                return '[invalid name]'
         else:
             names.append(force_text(part.verbose_name))
 

tests/test_utils.py

@@ -17,12 +17,16 @@
     verbose_field_name, verbose_lookup_expr, label_for_filter, raw_validation,
 )
 
-from .models import User
-from .models import Article
-from .models import Book
-from .models import HiredWorker
-from .models import Business
-from .models import NetworkSetting
+from .models import (
+    User,
+    Article,
+    Book,
+    HiredWorker,
+    Business,
+    NetworkSetting,
+    Company,
+    Account,
+)
 
 
 class GetFieldPartsTests(TestCase):
@@ -253,6 +257,26 @@ def test_lazy_text(self):
         verbose_name = verbose_field_name(User, 'username')
         self.assertEqual(verbose_name, 'username')
 
+    def test_forwards_fk(self):
+        verbose_name = verbose_field_name(Article, 'author')
+        self.assertEqual(verbose_name, 'author')
+
+    def test_backwards_fk(self):
+        # https://github.com/carltongibson/django-filter/issues/716
+
+        # related_name is set
+        verbose_name = verbose_field_name(Company, 'locations')
+        self.assertEqual(verbose_name, 'locations')
+
+        # related_name not set. Auto-generated relation is `article_set`
+        # _meta.get_field raises FieldDoesNotExist
+        verbose_name = verbose_field_name(User, 'article_set')
+        self.assertEqual(verbose_name, '[invalid name]')
+
+        # WRONG NAME! Returns ManyToOneRel with related_name == None.
+        verbose_name = verbose_field_name(User, 'article')
+        self.assertEqual(verbose_name, '[invalid name]')
+
 
 class VerboseLookupExprTests(TestCase):