gui: Issue an error instead of crashing when loading a drc file witho…

…ut a database opened.

Signed-off-by: Christian Costa <[email protected]>

src/gui/src/drcWidget.cpp

@@ -308,6 +308,14 @@ void DRCWidget::setLogger(utl::Logger* logger)
 
 void DRCWidget::selectReport()
 {
+  if (!block_) {
+    try {
+      logger_->error(utl::GUI, 104, "No database has been loaded");
+    } catch (const std::runtime_error& e) {
+    }
+    return;
+  }
+
   // OpenLane uses .drc and OpenROAD-flow-scripts uses .rpt
   QString filename = QFileDialog::getOpenFileName(
       this,