Bug fix/lazy loading on empty layers

superset-frontend/plugins/geoset-map-chart/src/GeoSetMultiMap/Multi.tsx

@@ -355,10 +355,6 @@ const DeckMulti = (props: DeckMultiProps) => {
                   handleFeatureClick(info, sliceFeatureInfoColumnNames),
               );
 
-              if (!newLayer) {
-                return null;
-              }
-
               const payloadData = payload?.data || [];
               const geometryType = getGeometryType(payloadData[0]?.geojson);
               let transformPropsGeojsonLayer =
@@ -483,13 +479,15 @@ const DeckMulti = (props: DeckMultiProps) => {
                 maxZoom: zoomSlider[1],
               };
 
-              const newLayerStates = layerStatesGenerator(
-                newLayer,
-                newLayerStateOptions,
-              );
+              // When the layer has no renderable data, return an entry with
+              // empty layerStates so the legend can show it as "loaded but
+              // empty" instead of spinning forever.
+              const newLayerStates = newLayer
+                ? layerStatesGenerator(newLayer, newLayerStateOptions)
+                : [];
 
               if (!newLayerStates.length) {
-                return null;
+                legendEntry.empty = true;
               }
 
               const layerFeatures: JsonObject[] =

superset-frontend/plugins/geoset-map-chart/src/components/MultiLegend.tsx

@@ -151,6 +151,13 @@ const CategoryRow = styled.div`
   gap: 8px;
 `;
 
+const NoDataLabel = styled.div`
+  font-size: 11px;
+  color: gray;
+  margin-bottom: 6px;
+  margin-left: -20px;
+`;
+
 const MetricBlock = styled.div`
   margin: 6px 0;
 `;
@@ -176,20 +183,22 @@ const Bounds = styled.div(
 `,
 );
 
-const VisibilityCheckbox = styled.input`
+const VisibilityCheckbox = styled.input<{ $empty?: boolean }>`
   width: 14px;
   height: 14px;
   cursor: pointer;
   margin: 0 !important;
   flex-shrink: 0;
+  ${({ $empty }) => $empty && 'accent-color: gray;'}
 `;
 
 // Checkbox that supports indeterminate state (shows minus sign when some but not all are selected)
 const IndeterminateCheckbox: React.FC<{
   checked: boolean;
   indeterminate: boolean;
   onChange: (e: React.ChangeEvent<HTMLInputElement>) => void;
-}> = ({ checked, indeterminate, onChange }) => {
+  $empty?: boolean;
+}> = ({ checked, indeterminate, onChange, $empty }) => {
   const ref = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
@@ -204,6 +213,7 @@ const IndeterminateCheckbox: React.FC<{
       type="checkbox"
       checked={checked}
       onChange={onChange}
+      $empty={$empty}
     />
   );
 };
@@ -249,17 +259,20 @@ const LegendEntryContent: React.FC<{
 
   return (
     <div>
-      {/* SIMPLE - show icon and slice name (skip when sizeEntry with a range handles the display) */}
+      {legendEntry.empty && <NoDataLabel>Visible but Empty</NoDataLabel>}
+      {/* SIMPLE - show icon and slice name (skip when sizeEntry handles the display) */}
       {legendEntry.type === 'simple' &&
         legendEntry.simpleStyle &&
         (!legendEntry.sizeEntry ||
-          legendEntry.sizeEntry.startSize === legendEntry.sizeEntry.endSize) && (
+          legendEntry.sizeEntry.startSize ===
+            legendEntry.sizeEntry.endSize) && (
           <CategoryRow>
             {showEntryCheckbox && (
               <VisibilityCheckbox
                 type="checkbox"
                 checked={isVisible}
                 onChange={onToggleVisibility}
+                $empty={legendEntry.empty}
               />
             )}
             <Swatch
@@ -313,6 +326,7 @@ const LegendEntryContent: React.FC<{
                         type="checkbox"
                         checked={item.enabled}
                         onChange={() => onToggleCategory(sliceId, item.label)}
+                        $empty={legendEntry.empty}
                       />
                     )}
                     <span>{item.label}</span>
@@ -338,6 +352,7 @@ const LegendEntryContent: React.FC<{
                         type="checkbox"
                         checked={isEnabled}
                         onChange={() => onToggleCategory(sliceId, cat.label)}
+                        $empty={legendEntry.empty}
                       />
                     )}
                     <Swatch
@@ -380,6 +395,7 @@ const LegendEntryContent: React.FC<{
                 type="checkbox"
                 checked={isVisible}
                 onChange={onToggleVisibility}
+                $empty={legendEntry.empty}
               />
               <Swatch
                 fill={fill}
@@ -511,6 +527,8 @@ export const MultiLegend: React.FC<MultiLegendProps> = ({
               someVisibleSomeNot || (isVisible && hasPartialCategories);
 
             const allLoading = entries.every(e => e.legendEntry.loading);
+            const allEmpty =
+              !allLoading && entries.every(e => e.legendEntry.empty);
 
             return (
               <Group key={displayTitle}>
@@ -523,6 +541,7 @@ export const MultiLegend: React.FC<MultiLegendProps> = ({
                       <IndeterminateCheckbox
                         checked={isVisible}
                         indeterminate={isIndeterminate}
+                        $empty={allEmpty}
                         onChange={e => {
                           e.stopPropagation();
                           setOptimisticVisibility(prev => ({

superset-frontend/plugins/geoset-map-chart/src/types.ts

@@ -106,6 +106,7 @@ export type LegendEntry = {
   isCombinedMetricSize?: boolean;
   initialCollapsed?: boolean; // Whether this legend entry starts collapsed
   loading?: boolean; // True for stub entries whose layer data is still loading
+  empty?: boolean; // True when layer loaded successfully but returned no data
 };
 
 export type LegendGroup = {