Add support for innergroup

Doxygen groups that are defined inside another group, either by scope or
by using \ingroup, are not automatically added to the documentation
unless an explicit reference is created.

This commit adds parsing of innergroup elements inside compound defs.

When using a group directive, .. doxygengroup:: myGroup, a new option
":inner:" must be added to include all innergroup elements. This allows
maintaining compatibility with previous projects.

Signed-off-by: Fabio Utzig <fabio.utzig@nordicsemi.no>

breathe/directives.py

@@ -406,6 +406,10 @@ class DoxygenNamespaceDirective(_DoxygenContentBlockDirective):
 
 class DoxygenGroupDirective(_DoxygenContentBlockDirective):
     kind = "group"
+    option_spec = {
+        **_DoxygenContentBlockDirective.option_spec,
+        "inner": flag,
+    }
 
 
 # TODO: is this comment still relevant?

breathe/renderer/sphinxrenderer.py

@@ -1024,6 +1024,12 @@ def render_derivedcompoundref(node):
         addnode('innerclass', lambda: self.render_iterable(node.innerclass))
         addnode('innernamespace', lambda: self.render_iterable(node.innernamespace))
 
+        if 'inner' in options:
+            for node in node.innergroup:
+                file_data = self.compound_parser.parse(node.refid)
+                inner = file_data.compounddef
+                addnode('innergroup', lambda: self.visit_compounddef(inner))
+
         nodelist = []
         for i, nodes_ in sorted(nodemap.items()):
             nodelist += nodes_

documentation/source/group.rst

@@ -10,7 +10,7 @@ source comments as cover in the `doxygen documentation`_.
 
 It takes the standard ``project``, ``path``, ``outline`` and ``no-link`` options
 and additionally the ``content-only``, ``members``, ``protected-members``,
-``private-members`` and ``undoc-members`` options.
+``private-members``, ``undoc-members`` and ``inner`` options.
 
 ``content-only``
    If this flag is specified, then the directive does not output the name of the
@@ -42,6 +42,11 @@ If you would like to always specify some combination of ``members``,
 use the :ref:`breathe_default_members <breathe-default-members>` configuration
 variable to set it in the ``conf.py``.
 
+``inner``
+   If specified, the groups that were defined inside this group, by either
+   defining them inside the scope of another group, or by using the Doxygen
+   \ingroup command, are also parsed and loaded.
+
 .. _doxygen documentation: http://www.stack.nl/~dimitri/doxygen/manual/grouping.html
 
 .. contents::