From edec998604ff6df5dadd8a1d4f1c65a4791db307 Mon Sep 17 00:00:00 2001
From: Taneli Hukkinen <3275109+hukkin@users.noreply.github.com>
Date: Wed, 2 Mar 2022 16:49:31 +0200
Subject: [PATCH] Document GFM whitespace

---
 mdit_py_plugins/tasklists/__init__.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mdit_py_plugins/tasklists/__init__.py b/mdit_py_plugins/tasklists/__init__.py
index d211e2b..40a6d67 100644
--- a/mdit_py_plugins/tasklists/__init__.py
+++ b/mdit_py_plugins/tasklists/__init__.py
@@ -23,6 +23,11 @@
 from markdown_it import MarkdownIt
 from markdown_it.token import Token
 
+# Regex string to match a whitespace character, as specified in
+# https://github.github.com/gfm/#whitespace-character
+# (spec version 0.29-gfm (2019-04-06))
+_GFM_WHITESPACE_RE = r"[ \t\n\v\f\r]"
+
 
 def tasklists_plugin(
     md: MarkdownIt,
@@ -145,4 +150,4 @@ def is_list_item(token):
 
     def starts_with_todo_markdown(token):
         # leading whitespace in a list item is already trimmed off by markdown-it
-        return re.match(r"\[[ xX]][ \t\n\v\f\r]+", token.content)
+        return re.match(rf"\[[ xX]]{_GFM_WHITESPACE_RE}+", token.content)