Suspense's fallback rendered manually with slot is not reactive

[posva]

Version

3.2.11

Reproduction link

sfc.vuejs.org/

Steps to reproduce

• Open link

What is expected?

The increment update suspense's fallback template

What is actually happening?

It stays as the initial value

---

From vuejs/router#1114

This is a very simplified version of what RouterView does to render its content

[edison1105]

as a workaround:

    <template #fallback>
      <div :key="percentage">
        <h1>Loading {{ percentage }} </h1>
      </div>
    </template>

empty dynamicChildren will also take the fast path in patchElement.
so I think maybe should avoid set dynamicChildren to an empty array.
or update the condition as below:

-if (dynamicChildren) {
+if (optimized && dynamicChildren) {
	patchBlockChildren(n1.dynamicChildren, dynamicChildren, el, parentComponent, parentSuspense, areChildrenSVG, slotScopeIds);
	if (parentComponent && parentComponent.type.__hmrId) {
		traverseStaticChildren(n1, n2);
	}
}