fix(virtual-core): keep a full range when the scroll offset is past the end of the list

.changeset/clamp-range-scroll-offset.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/virtual-core': patch
+---
+
+Keep a full viewport of rows in the range when the scroll offset is past the end of the list, as it is after the list shrinks and before the element reports its clamped position.

packages/virtual-core/src/index.ts

@@ -1860,16 +1860,23 @@ export class Virtualizer<
       this.getSize(),
       this.getScrollOffset(),
       this.options.lanes,
+      // scrollOffset is measured in the scroll element and the layout total
+      // from the list start, so the list ends scrollMargin further down.
+      this._getLayoutTotalSize() + this.options.scrollMargin,
     ],
-    (measurements, outerSize, scrollOffset, lanes) => {
+    (measurements, outerSize, scrollOffset, lanes, listEnd) => {
       if (measurements.length === 0 || outerSize === 0) {
         this.range = null
         return null
       }
+      // Until the element reports a clamped position (the list shrank, a
+      // rubber-band bounce), the offset can sit past the last row, which
+      // would leave only that row in the range.
+      const maxScrollOffset = Math.max(listEnd - outerSize, 0)
       this.range = calculateRangeImpl(
         measurements,
         outerSize,
-        scrollOffset,
+        Math.min(scrollOffset, maxScrollOffset),
         lanes,
         // Pass the typed array so binary search + forward-walk can read
         // start/end directly from Float64Array, skipping the Proxy traps.