Guard maxScrollSize against invalid values to avoid broken scale math.

Author: DivyamUp14

packages/virtual-core/src/index.ts

@@ -386,6 +386,8 @@ export class Virtualizer<
   private getScale = (): number => {
     const virtualTotal = this.getTotalVirtualSize()
     const max = this.options.maxScrollSize
+    // Invalid values disable scaling to keep math stable.
+    if (!Number.isFinite(max) || max <= 0) return 1
     return virtualTotal > max ? virtualTotal / max : 1
   }
 
@@ -786,7 +788,10 @@ export class Virtualizer<
     const scale = this.getScale()
     const tolerance = scale > 1 ? scale * 1.5 : 1.01
 
-    if (!targetChanged && Math.abs(targetOffset - this.getScrollOffset()) < tolerance) {
+    if (
+      !targetChanged &&
+      Math.abs(targetOffset - this.getScrollOffset()) < tolerance
+    ) {
       this.scrollState.stableFrames++
       if (this.scrollState.stableFrames >= STABLE_FRAMES) {
         // Final-pass exact landing. The reconcile-stable check uses a 1.01px
@@ -1676,7 +1681,11 @@ export class Virtualizer<
     // can reconcile against subpixel rounding by the browser.
     // _intendedScrollOffset is physical (compared against physical scrollTop readback).
     this._intendedScrollOffset = physicalOffset + (physicalAdj ?? 0)
-    this.options.scrollToFn(physicalOffset, { behavior, adjustments: physicalAdj }, this)
+    this.options.scrollToFn(
+      physicalOffset,
+      { behavior, adjustments: physicalAdj },
+      this,
+    )
   }
 
   measure = () => {