Fix #4018: htmlhelp: Add htmlhelp_file_suffix and htmlhelp_link_suffix

1 files changed, 5 insertions, 2 deletions

diff --git a/sphinx/builders/htmlhelp.py b/sphinx/builders/htmlhelp.py
index 49d48361e..52600ca21 100644
--- a/sphinx/builders/htmlhelp.py
+++ b/sphinx/builders/htmlhelp.py
@@ -19,6 +19,7 @@ from docutils import nodes
 
 from sphinx import addnodes
 from sphinx.builders.html import StandaloneHTMLBuilder
+from sphinx.config import string_classes
 from sphinx.environment.adapters.indexentries import IndexEntries
 from sphinx.locale import __
 from sphinx.util import logging
@@ -195,10 +196,10 @@ class HTMLHelpBuilder(StandaloneHTMLBuilder):
 
     def init(self):
         # type: () -> None
-        StandaloneHTMLBuilder.init(self)
-        # the output files for HTML help must be .html only
+        # the output files for HTML help is .html by default
         self.out_suffix = '.html'
         self.link_suffix = '.html'
+        StandaloneHTMLBuilder.init(self)
         # determine the correct locale setting
         locale = chm_locales.get(self.config.language)
         if locale is not None:
@@ -341,6 +342,8 @@ def setup(app):
     app.add_builder(HTMLHelpBuilder)
 
     app.add_config_value('htmlhelp_basename', lambda self: make_filename(self.project), None)
+    app.add_config_value('htmlhelp_file_suffix', None, 'html', string_classes)
+    app.add_config_value('htmlhelp_link_suffix', None, 'html', string_classes)
 
     return {
         'version': 'builtin',