addVectorLayerPrivate(): avoid crash in the non-nominal case when added a layer for a non-existing provider

rouault · rouault · commit 646f76f6215d · 2020-05-27T00:00:24.000+02:00
Backport of master commit 099df0b Fixes #31304
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -11473,7 +11473,7 @@ QgsVectorLayer *QgisApp::addVectorLayerPrivate( const QString &vectorLayerPath,
   {
     if ( guiWarning )
     {
-      QString message = layer->dataProvider()->error().message( QgsErrorMessage::Text );
+      QString message = layer->dataProvider() ? layer->dataProvider()->error().message( QgsErrorMessage::Text ) : tr( "Invalid provider" );
       QString msg = tr( "The layer %1 is not a valid layer and can not be added to the map. Reason: %2" ).arg( vectorLayerPath, message );
       visibleMessageBar()->pushMessage( tr( "Layer is not valid" ), msg, Qgis::Critical, messageTimeout() );
     }

Original file line number	Diff line number	Diff line change
`@@ -11473,7 +11473,7 @@ QgsVectorLayer *QgisApp::addVectorLayerPrivate( const QString &vectorLayerPath,`
`11473`	`11473`	`{`
`11474`	`11474`	`if ( guiWarning )`
`11475`	`11475`	`{`
`11476`		`- QString message = layer->dataProvider()->error().message( QgsErrorMessage::Text );`
	`11476`	`+ QString message = layer->dataProvider() ? layer->dataProvider()->error().message( QgsErrorMessage::Text ) : tr( "Invalid provider" );`
`11477`	`11477`	`QString msg = tr( "The layer %1 is not a valid layer and can not be added to the map. Reason: %2" ).arg( vectorLayerPath, message );`
`11478`	`11478`	`visibleMessageBar()->pushMessage( tr( "Layer is not valid" ), msg, Qgis::Critical, messageTimeout() );`
`11479`	`11479`	`}`