Deprecate: html5_ready and is_html5_writer_available()

CHANGES

@@ -53,6 +53,8 @@ Deprecated
   required
 * The ``language`` argument of ``sphinx.util.i18n:format_date()`` becomes
   required
+* ``sphinx.builders.html.html5_ready``
+* ``sphinx.util.docutils.is_html5_writer_available()``
 * ``sphinx.writers.latex.LaTeXWriter.docclasses``
 
 Features added

doc/extdev/deprecated.rst

@@ -42,6 +42,16 @@ The following is a list of deprecated interfaces.
      - 7.0
      - N/A
 
+   * - ``sphinx.builders.html.html5_ready``
+     - 5.0
+     - 7.0
+     - N/A
+
+   * - ``sphinx.util.docutils.is_html5_writer_available()``
+     - 5.0
+     - 7.0
+     - N/A
+
    * - ``sphinx.writers.latex.LaTeXWriter.docclasses``
      - 5.0
      - 7.0

sphinx/builders/html/__init__.py

@@ -23,6 +23,7 @@ from sphinx import version_info as sphinx_version
 from sphinx.application import Sphinx
 from sphinx.builders import Builder
 from sphinx.config import ENUM, Config
+from sphinx.deprecation import RemovedInSphinx70Warning, deprecated_alias
 from sphinx.domains import Domain, Index, IndexEntry
 from sphinx.environment.adapters.asset import ImageAdapter
 from sphinx.environment.adapters.indexentries import IndexEntries
@@ -33,7 +34,7 @@ from sphinx.locale import _, __
 from sphinx.search import js_index
 from sphinx.theming import HTMLThemeFactory
 from sphinx.util import isurl, logging, md5, progress_message, status_iterator
-from sphinx.util.docutils import is_html5_writer_available, new_document
+from sphinx.util.docutils import new_document
 from sphinx.util.fileutil import copy_asset
 from sphinx.util.i18n import format_date
 from sphinx.util.inventory import InventoryFile
@@ -41,13 +42,7 @@ from sphinx.util.matching import DOTFILES, Matcher, patmatch
 from sphinx.util.osutil import copyfile, ensuredir, os_path, relative_uri
 from sphinx.util.tags import Tags
 from sphinx.writers.html import HTMLTranslator, HTMLWriter
-
-# HTML5 Writer is available or not
-if is_html5_writer_available():
-    from sphinx.writers.html5 import HTML5Translator
-    html5_ready = True
-else:
-    html5_ready = False
+from sphinx.writers.html5 import HTML5Translator
 
 #: the filename for the inventory of objects
 INVENTORY_FILENAME = 'objects.inv'
@@ -344,7 +339,7 @@ class StandaloneHTMLBuilder(Builder):
 
     @property
     def default_translator_class(self) -> Type[nodes.NodeVisitor]:  # type: ignore
-        if not html5_ready or self.config.html4_writer:
+        if self.config.html4_writer:
             return HTMLTranslator
         else:
             return HTML5Translator
@@ -536,7 +531,7 @@ class StandaloneHTMLBuilder(Builder):
             'parents': [],
             'logo': logo,
             'favicon': favicon,
-            'html5_doctype': html5_ready and not self.config.html4_writer,
+            'html5_doctype': not self.config.html4_writer,
         }
         if self.theme:
             self.globalcontext.update(
@@ -1315,6 +1310,12 @@ import sphinxcontrib.serializinghtml  # NOQA
 import sphinx.builders.dirhtml  # NOQA
 import sphinx.builders.singlehtml  # NOQA
 
+deprecated_alias('sphinx.builders.html',
+                 {
+                     'html5_ready': True,
+                 },
+                 RemovedInSphinx70Warning)
+
 
 def setup(app: Sphinx) -> Dict[str, Any]:
     # builders

sphinx/util/docutils.py

@@ -2,6 +2,7 @@
 
 import os
 import re
+import warnings
 from contextlib import contextmanager
 from copy import copy
 from os import path
@@ -18,7 +19,8 @@ from docutils.parsers.rst.states import Inliner
 from docutils.statemachine import State, StateMachine, StringList
 from docutils.utils import Reporter, unescape
 
-from sphinx.deprecation import RemovedInSphinx60Warning, deprecated_alias
+from sphinx.deprecation import (RemovedInSphinx60Warning, RemovedInSphinx70Warning,
+                                deprecated_alias)
 from sphinx.errors import SphinxError
 from sphinx.locale import _, __
 from sphinx.util import logging
@@ -318,7 +320,9 @@ class NullReporter(Reporter):
 
 
 def is_html5_writer_available() -> bool:
-    return docutils.__version_info__ > (0, 13, 0)
+    warnings.warn('is_html5_writer_available() is deprecated.',
+                  RemovedInSphinx70Warning)
+    return True
 
 
 @contextmanager