Breathe fails to parse std::function typedef

[Luthaf]

If I have code containing a std::function typedef containing a template return parameter:

typedef std::function<std::unique_ptr<Format>(void)> function_type;

Then I get an error from breathe:

WARNING: Invalid definition: Expected end of definition. [error at 37]
  std::function<std::unique_ptr<Format>void)> chemfiles::function_type
  -------------------------------------^

The error goes away if I use a non-template return type (int, ...). It looks like the opening parentheses is being eaten somewhere.

[vermeeren]

Could you check if this problem still exists with latest Sphinx (1.7.5) + Breathe (4.9.0)? Support for C++ has been vastly improved since the issue was opened.

[Luthaf]

With Sphinx 1.7.5 and Breathe 4.9.1, I get the following error:

Main error:
  Invalid definition: Expected end of definition. [error at 13]
    std::function<std::unique_ptr<Format>void)> chemfiles::function_type
    -------------^
Potential other error:
  Error in parsing template argument list.
  If type argument:
    Invalid definition: Expected ">" or "," in template argument list. [error at 37]
      std::function<std::unique_ptr<Format>void)> chemfiles::function_type
      -------------------------------------^
  If non-type argument:
    Invalid definition: Expected ">" or "," in template argument list. [error at 37]
      std::function<std::unique_ptr<Format>void)> chemfiles::function_type
      -------------------------------------^

---

The offending code is no longer part of my project, here is the reproduction code I used:

// test.hpp

#include <functional>
#include <memory>

namespace chemfiles {
class Format;
/// Test
typedef std::function<std::unique_ptr<Format>(void)> function_type;

}

.. test.rst

.. doxygentypedef:: chemfiles::function_type

[jakobandersen]

With the code above from @Luthaf it looks like the missing opening parenthesis is already missing in the Doxygen XML.

[vermeeren]

I did a quick search through the Doxygen bug tracker.

https://bugzilla.gnome.org/query.cgi?format=advanced&product=doxygen

But could not find an issue for this.

Next steps will be opening a bug upstream, ref to it form here. Then probably implement a workaround specifically for std::functionin Breathe.

[t-b]

The doxygen output looks good AFAICJ:

<?xml version='1.0' encoding='UTF-8' standalone='no'?>
<doxygen xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="compound.xsd" version="1.8.15">
  <compounddef id="test_8cpp" kind="file" language="C++">
    <compoundname>test.cpp</compoundname>
    <includes local="no">functional</includes>
    <includes local="no">memory</includes>
    <incdepgraph>
      <node id="1">
        <label>functional</label>
      </node>
      <node id="0">
        <label>test.cpp</label>
        <link refid="test_8cpp"/>
        <childnode refid="1" relation="include">
        </childnode>
        <childnode refid="2" relation="include">
        </childnode>
      </node>
      <node id="2">
        <label>memory</label>
      </node>
    </incdepgraph>
    <innernamespace refid="namespacechemfiles">chemfiles</innernamespace>
    <briefdescription>
    </briefdescription>
    <detaileddescription>
    </detaileddescription>
    <programlisting>
<codeline lineno="1"><highlight class="preprocessor">#include<sp/>&lt;functional&gt;</highlight><highlight class="normal"></highlight></codeline>
<codeline lineno="2"><highlight class="normal"></highlight><highlight class="preprocessor">#include<sp/>&lt;memory&gt;</highlight><highlight class="normal"></highlight></codeline>
<codeline lineno="3"><highlight class="normal"></highlight></codeline>
<codeline lineno="4"><highlight class="normal"></highlight><highlight class="keyword">namespace<sp/></highlight><highlight class="normal"><ref refid="namespacechemfiles" kindref="compound">chemfiles</ref><sp/>{</highlight></codeline>
<codeline lineno="5"><highlight class="normal"></highlight><highlight class="keyword">class<sp/></highlight><highlight class="normal">Format;</highlight></codeline>
<codeline lineno="7"><highlight class="keyword">typedef</highlight><highlight class="normal"><sp/>std::function&lt;std::unique_ptr&lt;Format&gt;(void)&gt;<sp/>function_type;</highlight></codeline>
<codeline lineno="8"><highlight class="normal"></highlight></codeline>
<codeline lineno="9"><highlight class="normal">}</highlight></codeline>
    </programlisting>
    <location file="test.cpp"/>
  </compounddef>
</doxygen>

and sphinx 1.7.5 also handles

.. cpp:type:: function_type = std::function<std::unique_ptr<Format>(void)>

properly.

[vermeeren]

It is likely this has been fixed somewhere at some point, likely in Doxygen. Assuming fixed for now, comment if not the case.