qdoc: Fix regression in HeaderNode name handling

Node::plainFullName() constructs a fully qualified name for a node,
traversing the chain of parents until it comes across the root
namespace or a HeaderNode - but if the start node was already a header,
it incorrectly returned an empty string as the node name.

Fix the issue and add a test for output generated by \headerfile command.

Pick-to: 5.15
Fixes: QTBUG-84070
Change-Id: Ib214c53be8ed0eea98708219a00ba43970cd4177
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/auto/qdoc/generatedoutput/expected_output/headerfile-docbook/testheader.xml b/tests/auto/qdoc/generatedoutput/expected_output/headerfile-docbook/testheader.xml
new file mode 100644
index 000000000..f3461fb1a
--- /dev/null
+++ b/tests/auto/qdoc/generatedoutput/expected_output/headerfile-docbook/testheader.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<db:article xmlns:db="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.2" xml:lang="en">
+<db:info>
+<db:title></db:title>
+<db:productname>HeaderFile</db:productname>
+<db:titleabbrev>HeaderFile Reference Documentation</db:titleabbrev>
+<db:abstract>
+<db:para>A header file.</db:para>
+</db:abstract>
+</db:info>
+<db:variablelist>
+<db:varlistentry>
+<db:term>Header</db:term>
+<db:listitem>
+<db:para>TestHeader</db:para>
+</db:listitem>
+</db:varlistentry>
+</db:variablelist>
+<db:section xml:id="details">
+<db:title>Detailed Description</db:title>
+</db:section>
+</db:article>