remember and revert crs change

src/gui/vector/qgsvectorlayerproperties.cpp

@@ -300,6 +300,7 @@ QgsVectorLayerProperties::QgsVectorLayerProperties(
     }
   }
 
+
   mCrsSelector->setCrs( mLayer->crs() );
 
   //insert existing join info
@@ -557,7 +558,7 @@ void QgsVectorLayerProperties::syncToLayer()
 
   // populate the general information
   mLayerOrigNameLineEdit->setText( mLayer->name() );
-
+  mBackupCrs = mLayer->crs();
   //see if we are dealing with a pg layer here
   mSubsetGroupBox->setEnabled( true );
   txtSubsetSQL->setText( mLayer->subsetString() );
@@ -691,7 +692,7 @@ void QgsVectorLayerProperties::apply()
   {
     labelingDialog->writeSettingsToLayer();
   }
-
+  mBackupCrs = mLayer->crs();
   // apply legend settings
   mLegendWidget->applyToLayer();
   mLegendConfigEmbeddedWidget->applyToLayer();
@@ -917,6 +918,9 @@ void QgsVectorLayerProperties::onCancel()
     doc.setContent( mOldStyle.xmlData(), false, &myMessage, &errorLine, &errorColumn );
     mLayer->importNamedStyle( doc, myMessage );
   }
+
+  if ( mBackupCrs != mLayer->crs() )
+    mLayer->setCrs( mBackupCrs );
 }
 
 void QgsVectorLayerProperties::urlClicked( const QUrl &url )
@@ -979,6 +983,7 @@ QString QgsVectorLayerProperties::htmlMetadata()
 
 void QgsVectorLayerProperties::mCrsSelector_crsChanged( const QgsCoordinateReferenceSystem &crs )
 {
+
   QgsDatumTransformDialog::run( crs, QgsProject::instance()->crs(), this, mCanvas, tr( "Select Transformation for the vector layer" ) );
   mLayer->setCrs( crs );
   mMetadataFilled = false;

src/gui/vector/qgsvectorlayerproperties.h

@@ -251,6 +251,8 @@ class GUI_EXPORT QgsVectorLayerProperties : public QgsOptionsDialogBase, private
     QgsVectorLayerTemporalPropertiesWidget *mTemporalWidget = nullptr;
 
     QgsProviderSourceWidget *mSourceWidget = nullptr;
+
+    QgsCoordinateReferenceSystem mBackupCrs;
 
   private slots:
     void openPanel( QgsPanelWidget *panel );