fix: add bounds checking and fix off-by-one in qt/proposalmodel.cpp

Author: kwvg

src/qt/proposalmodel.cpp

@@ -359,13 +359,16 @@ void ProposalModel::setVotingParams(int newAbsVoteReq)
         this->nAbsVoteReq = newAbsVoteReq;
         // Changing either of the voting params may change the voting status
         // column. Emit signal to force recalculation.
-        Q_EMIT dataChanged(createIndex(0, Column::VOTING_STATUS), createIndex(rowCount(), Column::VOTING_STATUS));
+        Q_EMIT dataChanged(createIndex(0, Column::VOTING_STATUS), createIndex(rowCount() - 1, Column::VOTING_STATUS));
     }
 }
 
 const Proposal* ProposalModel::getProposalAt(const QModelIndex& index) const
 {
-    return m_data[index.row()];
+    if (index.isValid() && index.row() == std::clamp(index.row(), 0, m_data.count())) {
+        return m_data[index.row()];
+    }
+    return nullptr;
 }
 
 void ProposalModel::setDisplayUnit(BitcoinUnit display_unit) { this->m_display_unit = display_unit; }