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>

3 files changed, 111 insertions, 0 deletions

diff --git a/tests/auto/qdoc/generatedoutput/testdata/configs/headerfile.qdocconf b/tests/auto/qdoc/generatedoutput/testdata/configs/headerfile.qdocconf
new file mode 100644
index 000000000..b270556d1
--- /dev/null
+++ b/tests/auto/qdoc/generatedoutput/testdata/configs/headerfile.qdocconf
@@ -0,0 +1,17 @@
+project = HeaderFile
+moduleheader = testheader.h
+
+{includepaths,sourcedirs,headerdirs} += ../headerfile
+
+sources.fileextensions = "*.cpp *.qdoc"
+headers.fileextensions = "*.h"
+
+outputformats = HTML DocBook
+HTML.nosubdirs = true
+HTML.outputsubdir = headerfile
+DocBook.nosubdirs = true
+DocBook.outputsubdir = headerfile-docbook
+
+# zero warning tolerance
+warninglimit = 0
+warninglimit.enabled = true
diff --git a/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.cpp b/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.cpp
new file mode 100644
index 000000000..3a85b169c
--- /dev/null
+++ b/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.cpp
@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the tools applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "testheader.h"
+
+/*!
+    \headerfile <TestHeader>
+    \title Test Header
+    \inmodule TestCPP
+    \brief A header file.
+    \ingroup headers
+*/
+
+/*!
+    \group headers
+    \title Headers
+*/
+
+/*!
+    \fn void globalFunc()
+    \brief Global function.
+    \relates <TestHeader>
+*/
+
+/*!
+    \variable globalVar
+    \brief Global variable.
+    \relates <TestHeader>
+*/
+
+/*!
+    \enum Globals
+    \relates <TestHeader>
+    \value Glo
+    \value Bal
+*/
diff --git a/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.h b/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.h
new file mode 100644
index 000000000..94c625157
--- /dev/null
+++ b/tests/auto/qdoc/generatedoutput/testdata/headerfile/testheader.h
@@ -0,0 +1,33 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the tools applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#pragma once
+
+void globalFunc() {};
+enum Globals { Glo, Bal };
+const int globalVar;