From 773ccb0d11f5264b6cfe209115d9e80ca26fe861 Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Wed, 8 Apr 2020 11:40:32 -0400
Subject: [PATCH] Avoid using concurrency with Sphinx 3.0 due to a bug in that
 version

https://github.com/sphinx-doc/sphinx/issues/7438
https://github.com/randombit/botan/issues/2324
---
 src/scripts/build_docs.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/scripts/build_docs.py b/src/scripts/build_docs.py
index b773190144f..958c272d2d3 100755
--- a/src/scripts/build_docs.py
+++ b/src/scripts/build_docs.py
@@ -139,7 +139,14 @@ def sphinx_supports_concurrency():
     match = re.match(r'^(?:[a-zA-Z_-]+) v?(([0-9]+)\.([0-9]+))', output)
     # default to using concurrency when uncertain
     version = StrictVersion(match.group(1)) if match else StrictVersion('1.2')
-    return version >= StrictVersion('1.4')
+
+    if version < StrictVersion('1.4'):
+        # not supported
+        return False
+    if version >= StrictVersion('3.0'):
+        # Bug in Sphinx 3.0 https://github.com/sphinx-doc/sphinx/issues/7438
+        return False
+    return True
 
 def read_config(config):
     try: