The arguments of EpubBuilder.build_toc() is deprecated.

CHANGES

@@ -59,7 +59,8 @@ Deprecated
 * Support for evaluating Python 2 syntax is deprecated. This includes
   configuration files which should be converted to Python 3.
 * The arguments of ``EpubBuilder.build_mimetype()``,
-  ``EpubBuilder.build_container()``, ``EpubBuilder.bulid_content()``
+  ``EpubBuilder.build_container()``, ``EpubBuilder.bulid_content()``,
+  ``EpubBuilder.build_toc()``
 * The ``encoding`` argument of ``autodoc.Documenter.get_doc()``,
   ``autodoc.DocstringSignatureMixin.get_doc()``,
   ``autodoc.DocstringSignatureMixin._find_signature()``, and

doc/extdev/index.rst

@@ -243,7 +243,8 @@ The following is a list of deprecated interfaces.
      - N/A
 
    * - arguments of ``EpubBuilder.build_mimetype()``,
-       ``EpubBuilder.build_container()``, ``EpubBuilder.build_content()``
+       ``EpubBuilder.build_container()``, ``EpubBuilder.build_content()``,
+       ``EpubBuilder.build_toc()``
      - 2.0
      - 4.0
      - N/A

sphinx/builders/_epub_base.py

@@ -706,9 +706,15 @@ class EpubBuilder(StandaloneHTMLBuilder):
         metadata['navpoints'] = navpoints
         return metadata
 
-    def build_toc(self, outdir, outname):
+    def build_toc(self, outdir=None, outname='toc.ncx'):
         # type: (str, str) -> None
         """Write the metainfo file toc.ncx."""
+        if outdir:
+            warnings.warn('The arguments of EpubBuilder.build_toc() is deprecated.',
+                          RemovedInSphinx40Warning, stacklevel=2)
+        else:
+            outdir = self.outdir
+
         logger.info(__('writing %s file...'), outname)
 
         if self.config.epub_tocscope == 'default':

sphinx/builders/epub3.py

@@ -82,7 +82,7 @@ class Epub3Builder(_epub_base.EpubBuilder):
         self.build_container()
         self.build_content()
         self.build_navigation_doc(self.outdir, 'nav.xhtml')
-        self.build_toc(self.outdir, 'toc.ncx')
+        self.build_toc()
         self.build_epub(self.outdir, self.config.epub_basename + '.epub')
 
     def validate_config_value(self):