From ef7ca1472c1fdd085cffb8183b7ce8abbe9e2800 Mon Sep 17 00:00:00 2001
From: Chih-Hsuan Yen <yan12125@gmail.com>
Date: Thu, 18 Jul 2019 12:45:15 +0800
Subject: [PATCH] Add an html5lib patch for Python 3.9 compatibility

The patch is adapted from https://github.com/html5lib/html5lib-python/commit/4f9235752cea29c5a31721440578b430823a1e69

Closes https://github.com/pypa/pip/issues/6407
Closes https://github.com/pypa/pip/issues/6237
---
 news/6728.bugfix                             |  1 +
 src/pip/_vendor/html5lib/_trie/_base.py      |  5 +++-
 src/pip/_vendor/html5lib/treebuilders/dom.py |  5 +++-
 tasks/vendoring/patches/html5lib.patch       | 31 ++++++++++++++++++++
 4 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 news/6728.bugfix
 create mode 100644 tasks/vendoring/patches/html5lib.patch

diff --git a/news/6728.bugfix b/news/6728.bugfix
new file mode 100644
index 000000000..792105ddb
--- /dev/null
+++ b/news/6728.bugfix
@@ -0,0 +1 @@
+Make vendored html5lib compatible with Python 3.9.
diff --git a/src/pip/_vendor/html5lib/_trie/_base.py b/src/pip/_vendor/html5lib/_trie/_base.py
index a1158bbbf..6b71975f0 100644
--- a/src/pip/_vendor/html5lib/_trie/_base.py
+++ b/src/pip/_vendor/html5lib/_trie/_base.py
@@ -1,6 +1,9 @@
 from __future__ import absolute_import, division, unicode_literals
 
-from collections import Mapping
+try:
+    from collections.abc import Mapping
+except ImportError:  # Python 2.7
+    from collections import Mapping
 
 
 class Trie(Mapping):
diff --git a/src/pip/_vendor/html5lib/treebuilders/dom.py b/src/pip/_vendor/html5lib/treebuilders/dom.py
index dcfac220b..d8b530046 100644
--- a/src/pip/_vendor/html5lib/treebuilders/dom.py
+++ b/src/pip/_vendor/html5lib/treebuilders/dom.py
@@ -1,7 +1,10 @@
 from __future__ import absolute_import, division, unicode_literals
 
 
-from collections import MutableMapping
+try:
+    from collections.abc import MutableMapping
+except ImportError:  # Python 2.7
+    from collections import MutableMapping
 from xml.dom import minidom, Node
 import weakref
 
diff --git a/tasks/vendoring/patches/html5lib.patch b/tasks/vendoring/patches/html5lib.patch
new file mode 100644
index 000000000..92a34e4b2
--- /dev/null
+++ b/tasks/vendoring/patches/html5lib.patch
@@ -0,0 +1,31 @@
+diff --git a/src/pip/_vendor/html5lib/_trie/_base.py b/src/pip/_vendor/html5lib/_trie/_base.py
+index a1158bbb..6b71975f 100644
+--- a/src/pip/_vendor/html5lib/_trie/_base.py
++++ b/src/pip/_vendor/html5lib/_trie/_base.py
+@@ -1,6 +1,9 @@
+ from __future__ import absolute_import, division, unicode_literals
+ 
+-from collections import Mapping
++try:
++    from collections.abc import Mapping
++except ImportError:  # Python 2.7
++    from collections import Mapping
+ 
+ 
+ class Trie(Mapping):
+diff --git a/src/pip/_vendor/html5lib/treebuilders/dom.py b/src/pip/_vendor/html5lib/treebuilders/dom.py
+index dcfac220..d8b53004 100644
+--- a/src/pip/_vendor/html5lib/treebuilders/dom.py
++++ b/src/pip/_vendor/html5lib/treebuilders/dom.py
+@@ -1,7 +1,10 @@
+ from __future__ import absolute_import, division, unicode_literals
+ 
+ 
+-from collections import MutableMapping
++try:
++    from collections.abc import MutableMapping
++except ImportError:  # Python 2.7
++    from collections import MutableMapping
+ from xml.dom import minidom, Node
+ import weakref
+