1 files changed, 22 insertions, 3 deletions

diff --git a/sphinx/builders/htmlhelp.py b/sphinx/builders/htmlhelp.py
index 49d48361e..42ee05c4a 100644
--- a/sphinx/builders/htmlhelp.py
+++ b/sphinx/builders/htmlhelp.py
@@ -13,6 +13,7 @@ from __future__ import print_function
 
 import codecs
 import os
+import re
 from os import path
 
 from docutils import nodes
@@ -27,7 +28,7 @@ from sphinx.util.pycompat import htmlescape
 
 if False:
     # For type annotation
-    from typing import Any, Dict, IO, List, Tuple  # NOQA
+    from typing import Any, Dict, IO, List, Match, Tuple  # NOQA
     from sphinx.application import Sphinx  # NOQA
 
 
@@ -169,6 +170,24 @@ chm_locales = {
 }
 
 
+def chm_htmlescape(*args, **kwargs):
+    # type: (*Any, **Any) -> unicode
+    """
+    chm_htmlescape() is a wrapper of htmlescape().
+    .hhc/.hhk files don't recognize hex escaping, we need convert
+    hex escaping to decimal escaping. for example: `'` -> `'`
+    htmlescape() may generates a hex escaping `'` for single
+    quote `'`, this wrapper fixes this.
+    """
+    def convert(matchobj):
+        # type: (Match[unicode]) -> unicode
+        codepoint = int(matchobj.group(1), 16)
+        return '&#%d;' % codepoint
+    return re.sub(r'&#[xX]([0-9a-fA-F]+);',
+                  convert,
+                  htmlescape(*args, **kwargs))
+
+
 class HTMLHelpBuilder(StandaloneHTMLBuilder):
     """
     Builder that also outputs Windows HTML help project, contents and
@@ -278,7 +297,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
                         write_toc(subnode, ullevel)
                 elif isinstance(node, nodes.reference):
                     link = node['refuri']
-                    title = htmlescape(node.astext()).replace('"', '"')
+                    title = chm_htmlescape(node.astext()).replace('"', '"')
                     f.write(object_sitemap % (title, link))
                 elif isinstance(node, nodes.bullet_list):
                     if ullevel != 0:
@@ -311,7 +330,7 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
                     item = '    <param name="%s" value="%s">\n' % \
                         (name, value)
                     f.write(item)
-                title = htmlescape(title)
+                title = chm_htmlescape(title)
                 f.write('<LI> <OBJECT type="text/sitemap">\n')
                 write_param('Keyword', title)
                 if len(refs) == 0: