Avoid further crash with empty Chart document

following up on 8b5f8c26f007c8e67bc46b1b09340cae660d0b8b "Avoid crash with empty
Chart document", when you then close the Writer doc (discarding the changes), it
crashes in a chart::sidebar::ChartSidebarModifyListener::disposing call whose
mpParent (that was a ChartElementsPanel) is already destroyed.  The problem is
that the ChartElementsPanel ctor creates an mxListener pointing to this, then
calls Initialize, which calls xBroadcaster->addModifyListener(mxListener) and
then, during updateData, throws a RuntimeException when xDiagram is null in
getChartType, causing the ChartElementsPanel object to immediately be destroyed,
but the listener still registered.  This apparently needs fixing independently
of the immediate problem.  (The immediate problem is a regression introduced
with d7748842e96536daeb0c638c6f8d01d99b9a3e08 "hide grid and axes options in
chart elements if not supported, tdf#94297".)

Change-Id: I2fe4f2a59600664f6210456c65e033f9453f4cc9

1 files changed, 3 insertions, 0 deletions

diff --git a/chart2/source/controller/sidebar/ChartElementsPanel.cxx b/chart2/source/controller/sidebar/ChartElementsPanel.cxx
index 11e99561bcee..c037feadd012 100644
--- a/chart2/source/controller/sidebar/ChartElementsPanel.cxx
+++ b/chart2/source/controller/sidebar/ChartElementsPanel.cxx
@@ -391,6 +391,9 @@ css::uno::Reference<css::chart2::XChartType> getChartType(const css::uno::Refere
 {
     css::uno::Reference<css::chart2::XChartDocument> xChartDoc(xModel, css::uno::UNO_QUERY_THROW);
     css::uno::Reference<chart2::XDiagram > xDiagram = xChartDoc->getFirstDiagram();
+    if (!xDiagram.is()) {
+        return css::uno::Reference<css::chart2::XChartType>();
+    }
 
     css::uno::Reference<css::chart2::XCoordinateSystemContainer > xCooSysContainer( xDiagram, css::uno::UNO_QUERY_THROW );