"refid" attribute on "includes" (incType) XML nodes should be marked optional

[michaeljones]

Describe the bug
The incType refid attribute is not marked with use="optional".

doxygen/templates/xml/compound.xsd

Lines 101 to 108 in 682b594

	<xsd:complexType name="incType">
	<xsd:simpleContent>
	<xsd:extension base="xsd:string">
	<xsd:attribute name="refid" type="xsd:string" />
	<xsd:attribute name="local" type="DoxBool" />
	</xsd:extension>
	</xsd:simpleContent>
	</xsd:complexType>

Expected behavior
It is marked with use="optional" as it is only written conditionally:

doxygen/src/xmlgen.cpp

Lines 1290 to 1293 in 682b594

	if (ii->fileDef && !ii->fileDef->isReference()) // TODO: support external references
	{
	t << " refid=\"" << ii->fileDef->getOutputFileBase() << "\"";
	}

Screenshots
None.

To Reproduce
The issue is visible when creating a parser for the XML based on the XSD which expects non-optional attributes to be there. This is done in Rust as part of the Docleaf project: https://github.com/docleaf-labs/docleaf

Version
I'm using 1.9.7 locally but the issue is visible in the code on main (if I correct in my interpretation of the code/xsd.)

Stack trace
None

Additional context
None

[albert-github]

Sounds all very reasonable.
Please always add an example showing the problem, so we can reproduce the problem.
Based on the description given: I've just pushed a proposed patch, pull request #10214

[michaeljones]

Yeah, fair. I encountered the code in a somewhat complex set up and lazily hoped the code references would be enough. Sorry about that.

If you look at xml/example_8h.xml in the attached zip file, you'll see line 5 is:

<includes local="yes">my_other_file.h</includes>

Which is an includes tag without a refid. I assume it happens for any inclusion of a file that is outside of the Doxygen code base or that Doxygen can't find.

includes-xml-refid-error.zip

[albert-github]

Code has been integrated in master on GitHub (please don't close the issue as this will be done at the moment of an official release).

[doxygen]

This issue was previously marked 'fixed but not released',
which means it should be fixed in doxygen version 1.9.8.
Please verify if this is indeed the case. Reopen the
issue if you think it is not fixed and please include any additional information
that you think can be relevant (preferably in the form of a self-contained example).