qdoc: Don't let a QML type be its own base type

When qdoc runs without one or more of the index files for
the modules it depends on, there was a chance it could set
a QML type's base type to point to the QML type itself.
This resulted in an infinite loop, which crashed qdoc with
a bad alloc error. qdoc has now been changed so that it
refuses to set a QML type's base type to itself.

Change-Id: I08e8959ddb67b2d1f3b1bf44d9dc48624bafebfa
Task-number: QTBUG-50163
Reviewed-by: Martin Smith <martin.smith@theqtcompany.com>

2 files changed, 9 insertions, 3 deletions

diff --git a/src/qdoc/cppcodemarker.cpp b/src/qdoc/cppcodemarker.cpp
index d4e7546e9..b0e4e823d 100644
--- a/src/qdoc/cppcodemarker.cpp
+++ b/src/qdoc/cppcodemarker.cpp
@@ -1306,6 +1306,12 @@ QList<Section> CppCodeMarker::qmlSections(QmlTypeNode* qmlTypeNode, SynopsisStyl
                     }
                     ++c;
                 }
+                if (current->qmlBaseNode() == current) {
+                    qDebug() << "qdoc internal error: circular type definition."
+                             << "QML type" << current->name()
+                             << "can't be its own base type";
+                    break;
+                }
                 current = current->qmlBaseNode();
                 while (current) {
                     if (current->isAbstract())
diff --git a/src/qdoc/qdocdatabase.cpp b/src/qdoc/qdocdatabase.cpp
index 1707963c8..e3331a4f0 100644
--- a/src/qdoc/qdocdatabase.cpp
+++ b/src/qdoc/qdocdatabase.cpp
@@ -1460,21 +1460,21 @@ void QDocDatabase::resolveQmlInheritance(Aggregate* root)
             QmlTypeNode* qcn = static_cast<QmlTypeNode*>(child);
             if (qcn->qmlBaseNodeNotSet() && !qcn->qmlBaseName().isEmpty()) {
                 QmlTypeNode* bqcn = static_cast<QmlTypeNode*>(previousSearches.value(qcn->qmlBaseName()));
-                if (bqcn)
+                if (bqcn && (bqcn != qcn))
                     qcn->setQmlBaseNode(bqcn);
                 else {
                     if (!qcn->importList().isEmpty()) {
                         const ImportList& imports = qcn->importList();
                         for (int i=0; i<imports.size(); ++i) {
                             bqcn = findQmlType(imports[i], qcn->qmlBaseName());
-                            if (bqcn)
+                            if (bqcn && (bqcn != qcn))
                                 break;
                         }
                     }
                     if (bqcn == 0) {
                         bqcn = findQmlType(QString(), qcn->qmlBaseName());
                     }
-                    if (bqcn) {
+                    if (bqcn && (bqcn != qcn)) {
                         qcn->setQmlBaseNode(bqcn);
                         previousSearches.insert(qcn->qmlBaseName(), bqcn);
                     }