From: Andrey Rahmatullin <wrar@debian.org>
Date: Sun, 4 Aug 2019 22:38:47 +0500
Subject: Use local intersphinx files.

---
 docs/conf.py | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/docs/conf.py b/docs/conf.py
index 77f0d35..5f984f2 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,11 +1,25 @@
 # -*- coding: utf-8 -*-
-import os, pkg_resources, datetime, time
+import os, pkg_resources, datetime, time, sys
 
-intersphinx_mapping = {
-    'python': ('https://docs.python.org/3/', None),
-    'sphinx': ('https://www.sphinx-doc.org/en/stable/', None),
-    'myst': ('https://myst-parser.readthedocs.io/en/latest', None),
-}
+def check_object_path(key, url, path):
+    if path and os.path.isfile(path):
+        return {key: (url, path)}
+    return {}
+
+intersphinx_mapping = {}
+intersphinx_mapping.update(
+    check_object_path('python',
+                      'https://docs.python.org/3/',
+                      '/usr/share/doc/python%d.%d/html/objects.inv' % \
+                       sys.version_info[:2]))
+intersphinx_mapping.update(
+    check_object_path('sphinx',
+                      'http://www.sphinx-doc.org/en/master/',
+                      '/usr/share/doc/sphinx-doc/html/objects.inv'))
+intersphinx_mapping.update(
+    check_object_path('myst',
+                      'https://myst-parser.readthedocs.io/en/latest',
+                      None))  # the docs are not packaged
 
 extensions = [
     'sphinx.ext.autodoc',