Fix crash on exit

nyalldawson · nyalldawson · commit 14f0a832ec50 · 2018-05-03T11:23:23.000+10:00
Because the map canvas is destroyed before the project instance, and QgsProject emits the labelingEngineSettingsChange signal during its destructor, the lambda slot was getting executed with a dangling map canvas pointer. Correctly set the receiver in the lambda connection instead so that the connection gets destroyed along with the canvas. (cherry-picked from b683291)
diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -3184,7 +3184,7 @@ void QgisApp::setupConnections()
   } );
 
   connect( QgsProject::instance(), &QgsProject::labelingEngineSettingsChanged,
-           this, [ = ]
+           mMapCanvas, [ = ]
   {
     mMapCanvas->setLabelingEngineSettings( QgsProject::instance()->labelingEngineSettings() );
   } );

Original file line number	Diff line number	Diff line change
`@@ -3184,7 +3184,7 @@ void QgisApp::setupConnections()`
`3184`	`3184`	`} );`
`3185`	`3185`
`3186`	`3186`	`connect( QgsProject::instance(), &QgsProject::labelingEngineSettingsChanged,`
`3187`		`- this, [ = ]`
	`3187`	`+ mMapCanvas, [ = ]`
`3188`	`3188`	`{`
`3189`	`3189`	`mMapCanvas->setLabelingEngineSettings( QgsProject::instance()->labelingEngineSettings() );`
`3190`	`3190`	`} );`