Fix crash when filtering out warnings from issues pane

Do not send endRemoveRows if we never sent beginRemoveRows.
Fix up of 702d6a6914

Task-number: QTCREATORBUG-20741
Change-Id: If22a18e6426c8b4041924a170d5927ab9d11ccdf
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/projectexplorer/taskmodel.cpp

@@ -337,7 +337,10 @@ TaskFilterModel::TaskFilterModel(TaskModel *sourceModel, QObject *parent) : QAbs
     connect(m_sourceModel, &QAbstractItemModel::rowsRemoved,
             this, [this](const QModelIndex &parent, int, int) {
         QTC_ASSERT(!parent.isValid(), return);
-        endRemoveRows();
+        if (m_beginRemoveRowsSent) {
+            m_beginRemoveRowsSent = false;
+            endRemoveRows();
+        }
     });
 
     connect(m_sourceModel, &QAbstractItemModel::modelReset,
@@ -430,6 +433,7 @@ void TaskFilterModel::handleNewRows(const QModelIndex &index, int first, int las
 
 void TaskFilterModel::handleRowsAboutToBeRemoved(const QModelIndex &index, int first, int last)
 {
+    m_beginRemoveRowsSent = false;
     QTC_ASSERT(!index.isValid(), return);
 
     const QPair<int, int> range = findFilteredRange(first, last, m_mapping);
@@ -437,6 +441,7 @@ void TaskFilterModel::handleRowsAboutToBeRemoved(const QModelIndex &index, int f
         return;
 
     beginRemoveRows(QModelIndex(), range.first, range.second);
+    m_beginRemoveRowsSent = true;
     m_mapping.erase(m_mapping.begin() + range.first, m_mapping.begin() + range.second + 1);
     const int sourceRemovedCount = (last - first) + 1;
     for (int i = range.first; i < m_mapping.count(); ++i)

src/plugins/projectexplorer/taskmodel.h

@@ -165,6 +165,7 @@ private:
     void updateMapping() const;
     bool filterAcceptsTask(const Task &task) const;
 
+    bool m_beginRemoveRowsSent = false;
     bool m_includeUnknowns;
     bool m_includeWarnings;
     bool m_includeErrors;