Merge branch '3.x' into merge_3.x_into_master

Resolved Conflicts:
	sphinx/texinputs/sphinxpackagefootnote.sty

1 files changed, 16 insertions, 1 deletions

diff --git a/sphinx/ext/autodoc/directive.py b/sphinx/ext/autodoc/directive.py
index 72407de35..69177f271 100644
--- a/sphinx/ext/autodoc/directive.py
+++ b/sphinx/ext/autodoc/directive.py
@@ -32,6 +32,9 @@ AUTODOC_DEFAULT_OPTIONS = ['members', 'undoc-members', 'inherited-members',
                            'ignore-module-all', 'exclude-members', 'member-order',
                            'imported-members']
 
+AUTODOC_EXTENDABLE_OPTIONS = ['members', 'private-members', 'special-members',
+                              'exclude-members']
+
 
 class DummyOptionSpec(dict):
     """An option_spec allows any options."""
@@ -76,7 +79,19 @@ def process_documenter_options(documenter: "Type[Documenter]", config: Config, o
         else:
             negated = options.pop('no-' + name, True) is None
             if name in config.autodoc_default_options and not negated:
-                options[name] = config.autodoc_default_options[name]
+                if name in options and isinstance(config.autodoc_default_options[name], str):
+                    # take value from options if present or extend it
+                    # with autodoc_default_options if necessary
+                    if name in AUTODOC_EXTENDABLE_OPTIONS:
+                        if options[name] is not None and options[name].startswith('+'):
+                            options[name] = ','.join([config.autodoc_default_options[name],
+                                                      options[name][1:]])
+                else:
+                    options[name] = config.autodoc_default_options[name]
+
+            elif options.get(name) is not None:
+                # remove '+' from option argument if there's nothing to merge it with
+                options[name] = options[name].lstrip('+')
 
     return Options(assemble_option_dict(options.items(), documenter.option_spec))