From bdb747a5f2ffe7356c722c67184a2bc1e24c7f73 Mon Sep 17 00:00:00 2001
From: Sergey Fedoseev <fedoseev.sergey@gmail.com>
Date: Sun, 12 Nov 2017 05:38:29 +0500
Subject: [PATCH] Simplified Field.get_choices().

---
 django/db/models/fields/__init__.py | 39 +++++++++++++----------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index b2e9b18351..4a006bc85d 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -3,6 +3,7 @@ import copy
 import datetime
 import decimal
 import itertools
+import operator
 import uuid
 import warnings
 from base64 import b64decode, b64encode
@@ -790,31 +791,25 @@ class Field(RegisterLookupMixin):
         Return choices with a default blank choices included, for use
         as <select> choices for this field.
         """
-        blank_defined = False
-        choices = list(self.choices) if self.choices else []
-        named_groups = choices and isinstance(choices[0][1], (list, tuple))
-        if not named_groups:
-            for choice, __ in choices:
-                if choice in ('', None):
-                    blank_defined = True
-                    break
-
-        first_choice = (blank_choice if include_blank and
-                        not blank_defined else [])
         if self.choices:
-            return first_choice + choices
+            choices = list(self.choices)
+            if include_blank:
+                named_groups = isinstance(choices[0][1], (list, tuple))
+                blank_defined = not named_groups and any(choice in ('', None) for choice, __ in choices)
+                if not blank_defined:
+                    choices = blank_choice + choices
+            return choices
         rel_model = self.remote_field.model
         limit_choices_to = limit_choices_to or self.get_limit_choices_to()
-        if hasattr(self.remote_field, 'get_related_field'):
-            lst = [(getattr(x, self.remote_field.get_related_field().attname),
-                   smart_text(x))
-                   for x in rel_model._default_manager.complex_filter(
-                       limit_choices_to)]
-        else:
-            lst = [(x.pk, smart_text(x))
-                   for x in rel_model._default_manager.complex_filter(
-                       limit_choices_to)]
-        return first_choice + lst
+        choice_func = operator.attrgetter(
+            self.remote_field.get_related_field().attname
+            if hasattr(self.remote_field, 'get_related_field')
+            else 'pk'
+        )
+        return (blank_choice if include_blank else []) + [
+            (choice_func(x), smart_text(x))
+            for x in rel_model._default_manager.complex_filter(limit_choices_to)
+        ]
 
     def value_to_string(self, obj):
         """