When a vector tile style rule is set to "(all layers)", ensure

that we correctly fetch the attributes required for the style's
filter and labeling for all layers

Fixes broken rendering of vector tile style rules set to (all layers)
which use attribute filters

src/core/vectortile/qgsvectortilemvtdecoder.cpp

@@ -110,7 +110,20 @@ QgsVectorTileFeatures QgsVectorTileMVTDecoder::layerFeatures( const QMap<QString
       continue;
 
     QVector<QgsFeature> layerFeatures;
-    const QgsFields layerFields = perLayerFields[layerName];
+    QgsFields layerFields = perLayerFields[layerName];
+
+    const auto allLayerFields = perLayerFields.find( QString() );
+    if ( allLayerFields != perLayerFields.end() )
+    {
+      // need to add the fields from any "all layer" rules to every layer
+      for ( const QgsField &field : allLayerFields.value() )
+      {
+        if ( layerFields.lookupField( field.name() ) == -1 )
+        {
+          layerFields.append( field );
+        }
+      }
+    }
 
     // figure out how field indexes in MVT encoding map to field indexes in QgsFields (we may not use all available fields)
     QHash<int, int> tagKeyIndexToFieldIndex;

tests/src/core/testqgsvectortilelayer.cpp

@@ -77,6 +77,7 @@ class TestQgsVectorTileLayer : public QgsTest
     void test_polygonWithMarker();
 
     void test_styleMinZoomBeyondTileMaxZoom();
+    void test_filterRuleAllLayers();
 };
 
 
@@ -637,6 +638,47 @@ void TestQgsVectorTileLayer::test_styleMinZoomBeyondTileMaxZoom()
                                    QStringLiteral( "render_test_style_min_zoom" ), *mMapSettings, 0, 15 ) );
 }
 
+void TestQgsVectorTileLayer::test_filterRuleAllLayers()
+{
+  // test using a filter with field access for an "all layers" rule
+  QgsDataSourceUri ds;
+  ds.setParam( "type", "mbtiles" );
+  ds.setParam( "url", QString( "/%1/mbtiles_vt.mbtiles" ).arg( mDataDir ) );
+  std::unique_ptr< QgsVectorTileLayer > layer = std::make_unique< QgsVectorTileLayer >( ds.encodedUri(), "Vector Tiles Test" );
+  QVERIFY( layer->isValid() );
+
+  mMapSettings->setLayers( QList<QgsMapLayer *>() << layer.get() );
+
+  const QColor lineStrokeColor = Qt::blue;
+  const double lineStrokeWidth = DEFAULT_LINE_WIDTH * 4;
+
+  QgsSimpleLineSymbolLayer *lineSymbolLayer = new QgsSimpleLineSymbolLayer;
+  lineSymbolLayer->setColor( lineStrokeColor );
+  lineSymbolLayer->setWidth( lineStrokeWidth );
+  QgsLineSymbol *lineSymbol = new QgsLineSymbol( QgsSymbolLayerList() << lineSymbolLayer );
+
+  QgsVectorTileBasicRendererStyle st( QStringLiteral( "Lines" ), QString(), Qgis::GeometryType::Line );
+  st.setFilterExpression( QStringLiteral( "\"Name\"='Highway'" ) );
+  st.setSymbol( lineSymbol );
+
+  QgsSimpleFillSymbolLayer *fillSymbolLayer = new QgsSimpleFillSymbolLayer;
+  fillSymbolLayer->setColor( Qt::white );
+  fillSymbolLayer->setStrokeStyle( Qt::NoPen );
+  QgsFillSymbol *fillSymbol = new QgsFillSymbol( QgsSymbolLayerList() << fillSymbolLayer );
+
+  QgsVectorTileBasicRendererStyle bgst( QStringLiteral( "background" ), QStringLiteral( "background" ), Qgis::GeometryType::Polygon );
+  bgst.setSymbol( fillSymbol );
+
+  QgsVectorTileBasicRenderer *rend = new QgsVectorTileBasicRenderer;
+  rend->setStyles( QList<QgsVectorTileBasicRendererStyle>() << bgst << st );
+  layer->setRenderer( rend );  // takes ownership
+
+  mMapSettings->setExtent( layer->extent() );
+  mMapSettings->setDestinationCrs( layer->crs() );
+  QVERIFY( renderMapSettingsCheck( QStringLiteral( "render_test_filter_all_layers" ),
+                                   QStringLiteral( "render_test_filter_all_layers" ), *mMapSettings, 0, 15 ) );
+}
+
 
 QGSTEST_MAIN( TestQgsVectorTileLayer )
 #include "testqgsvectortilelayer.moc"