make sure listbox doesnt add extranous padding above the empty state when empty or loading

since we are now rendering the virtualizer body if there is a loading sentinel, we dont want to add padding to the body rect calc since that will push the renderEmpty node down. Not a problem in TableLayout it seems

Author: LFDanLu

packages/@react-spectrum/s2/src/ComboBox.tsx

@@ -590,8 +590,6 @@ const ComboboxInner = forwardRef(function ComboboxInner(props: ComboBoxProps<any
       </>
     );
   }
-
-  let isEmptyOrLoading = state?.collection?.size === 0 || (state?.collection.size === 1 && state.collection.getItem(state.collection.getFirstKey()!)!.type === 'loader');
   let scale = useScale();
 
   return (
@@ -689,10 +687,7 @@ const ComboboxInner = forwardRef(function ComboboxInner(props: ComboBoxProps<any
               layout={ListLayout}
               layoutOptions={{
                 estimatedRowHeight: 32,
-                // TODO: can we get rid of this and instead handle padding else where other than the layout options? Kinda gross that we need to do this check.
-                // Perhaps can consider only applying padding if the collection actually has content since the renderEmptyState content is outside the virtualizer
-                // Otherwise could consider moving renderEmptyState into the collection...
-                padding: isEmptyOrLoading ? 0 : 8,
+                padding: 8,
                 estimatedHeadingHeight: 50,
                 loaderHeight: LOADER_ROW_HEIGHTS[size][scale]
               }}>

packages/@react-stately/layout/src/ListLayout.ts

@@ -255,9 +255,13 @@ export class ListLayout<T, O extends ListLayoutOptions = ListLayoutOptions> exte
     let collection = this.virtualizer!.collection;
     let skipped = 0;
     let nodes: LayoutNode[] = [];
+    let isEmptyOrLoading = collection?.size === 0 || (collection.size === 1 && collection.getItem(collection.getFirstKey()!)!.type === 'loader');
+    if (isEmptyOrLoading) {
+      y = 0;
+    }
+
     for (let node of collection) {
       let rowHeight = (this.rowHeight ?? this.estimatedRowHeight ?? DEFAULT_HEIGHT) + this.gap;
-
       // Skip rows before the valid rectangle unless they are already cached.
       if (node.type === 'item' && y + rowHeight < this.requestedRect.y && !this.isValid(node, y)) {
         y += rowHeight;
@@ -289,7 +293,7 @@ export class ListLayout<T, O extends ListLayoutOptions = ListLayoutOptions> exte
     }
 
     y -= this.gap;
-    y += this.padding;
+    y += isEmptyOrLoading ? 0 : this.padding;
     this.contentSize = new Size(this.virtualizer!.visibleRect.width, y);
     return nodes;
   }