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>

1 files changed, 6 insertions, 0 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())