fix(runtime): make isSameVnode return false on initial render in a hy…

…dration case

src/runtime/vdom/test/vdom-render.spec.tsx

@@ -0,0 +1,28 @@
+import { isSameVnode } from '../vdom-render'
+
+describe('isSameVnode', () => {
+  it('should detect objectively same nodes', () => {
+    const vnode1: any = {
+      $tag$: 'div',
+      $key$: '1',
+    }
+    const vnode2: any = {
+      $tag$: 'div',
+      $key$: '1',
+    }
+    expect(isSameVnode(vnode1, vnode2)).toBe(true)
+  })
+
+  it('should return false in case of hyration', () => {
+    const vnode1: any = {
+      $tag$: 'slot',
+      $key$: '1',
+      $nodeId$: 1,
+    }
+    const vnode2: any = {
+      $tag$: 'slot',
+      $key$: '1',
+    }
+    expect(isSameVnode(vnode1, vnode2, true)).toBe(false)
+  })
+})

src/runtime/vdom/vdom-render.ts

@@ -609,6 +609,12 @@ export const isSameVnode = (leftVNode: d.VNode, rightVNode: d.VNode, isInitialRe
   // compare if two vnode to see if they're "technically" the same
   // need to have the same element tag, and same key to be the same
   if (leftVNode.$tag$ === rightVNode.$tag$) {
+    // We can skip key comparison if this is the initial render of the vdom
+    // in the case of hydration
+    if ('$nodeId$' in leftVNode && isInitialRender) {
+      return false;
+    }
+
     if (BUILD.slotRelocation && leftVNode.$tag$ === 'slot') {
       return leftVNode.$name$ === rightVNode.$name$;
     }