Fix crashes in expression widget when no layer is available

Fixes #40763 (cherry picked from commit e0e21a7)
qgis · Jan 1, 2021 · d9497e8d0f268e5147f16f938d08eb9bd1209e7d · d9497e8
1 parent c6ac5a6
commit d9497e8d0f268e5147f16f938d08eb9bd1209e7d
Unified Split

Showing with 8 additions and 5 deletions.

+1 −1 src/core/qgsfeatureexpressionvaluesgatherer.h

+1 −1 src/core/qgsfeaturefiltermodel.cpp

+6 −3 src/core/qgsfeaturepickermodelbase.cpp
diff --git a/src/core/qgsfeatureexpressionvaluesgatherer.h b/src/core/qgsfeatureexpressionvaluesgatherer.h
@@ -71,7 +71,7 @@ class QgsFeatureExpressionValuesGatherer: public QThread
       Entry( const QgsFeatureId &_featureId, const QString &_value, const QgsVectorLayer *layer )
         : featureId( _featureId )
         , value( _value )
-        , feature( QgsFeature( layer->fields() ) )
+        , feature( QgsFeature( layer ? layer->fields() : QgsFields() ) )
       {}
 
       QVariantList identifierFields;

diff --git a/src/core/qgsfeaturefiltermodel.cpp b/src/core/qgsfeaturefiltermodel.cpp
@@ -83,7 +83,7 @@ QgsFeatureExpressionValuesGatherer::Entry QgsFeatureFilterModel::createEntry( co
   for ( const QVariant &v : constValues )
     values << QStringLiteral( "(%1)" ).arg( v.toString() );
 
-  return QgsFeatureExpressionValuesGatherer::Entry( constValues, values.join( QLatin1Char( ' ' ) ), QgsFeature( sourceLayer()->fields() ) );
+  return QgsFeatureExpressionValuesGatherer::Entry( constValues, values.join( QLatin1Char( ' ' ) ), QgsFeature( sourceLayer() ? sourceLayer()->fields() : QgsFields() ) );
 }
 
 bool QgsFeatureFilterModel::compareEntries( const QgsFeatureExpressionValuesGatherer::Entry &a, const QgsFeatureExpressionValuesGatherer::Entry &b ) const

diff --git a/src/core/qgsfeaturepickermodelbase.cpp b/src/core/qgsfeaturepickermodelbase.cpp
@@ -50,11 +50,14 @@ void QgsFeaturePickerModelBase::setSourceLayer( QgsVectorLayer *sourceLayer )
     return;
 
   mSourceLayer = sourceLayer;
-  mExpressionContext = sourceLayer->createExpressionContext();
+  if ( mSourceLayer )
+    mExpressionContext = mSourceLayer->createExpressionContext();
+
   reload();
   emit sourceLayerChanged();
 
-  setDisplayExpression( sourceLayer->displayExpression() );
+  if ( mSourceLayer )
+    setDisplayExpression( mSourceLayer->displayExpression() );
 }
 
 
@@ -279,7 +282,7 @@ void QgsFeaturePickerModelBase::updateCompleter()
     // We got strings for a filter selection
     std::sort( entries.begin(), entries.end(), []( const QgsFeatureExpressionValuesGatherer::Entry & a, const QgsFeatureExpressionValuesGatherer::Entry & b ) { return a.value.localeAwareCompare( b.value ) < 0; } );
 
-    if ( mAllowNull )
+    if ( mAllowNull && mSourceLayer )
     {
       entries.prepend( QgsFeatureExpressionValuesGatherer::nullEntry( mSourceLayer ) );
     }