From e8c2c8730128ef69fe95107e18deedb88cd36851 Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Sat, 12 Jan 2019 20:33:09 +0900
Subject: [PATCH] Fix #5928: KeyError: 'DOCUTILSCONFIG' when running build

---
 CHANGES                 | 1 +
 sphinx/util/docutils.py | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index b34a19431..0a65edb10 100644
--- a/CHANGES
+++ b/CHANGES
@@ -24,6 +24,7 @@ Bugs fixed
 * #5755: C++, fix duplicate declaration error on function templates with constraints
   in the return type.
 * C++, parse unary right fold expressions and binary fold expressions.
+* #5928: KeyError: 'DOCUTILSCONFIG' when running build
 
 Testing
 --------
diff --git a/sphinx/util/docutils.py b/sphinx/util/docutils.py
index ccd6410ec..e8adc58b3 100644
--- a/sphinx/util/docutils.py
+++ b/sphinx/util/docutils.py
@@ -131,7 +131,7 @@ def using_user_docutils_conf(confdir):
         yield
     finally:
         if docutilsconfig is None:
-            os.environ.pop('DOCUTILSCONFIG')
+            os.environ.pop('DOCUTILSCONFIG', None)
         else:
             os.environ['DOCUTILSCONFIG'] = docutilsconfig