We should not always set to hydration

compat/test/browser/suspense-hydration.test.js

@@ -15,6 +15,7 @@ import {
 } from '../../../test/_util/helpers';
 import { ul, li, div } from '../../../test/_util/dom';
 import { createLazy, createSuspenseLoader } from './suspense-utils';
+import { render } from 'preact';
 
 /* eslint-env browser, mocha */
 describe('suspense hydration', () => {
@@ -97,30 +98,6 @@ describe('suspense hydration', () => {
  });
  });
 
- it('should leave DOM untouched when suspending while hydrating', () => {
- scratch.innerHTML = '<!-- test --><div>Hello</div>';
- clearLog();
-
- const [Lazy, resolve] = createLazy();
- hydrate(
- <Suspense>
- <Lazy />
- </Suspense>,
- scratch
- );
- rerender(); // Flush rerender queue to mimic what preact will really do
- expect(scratch.innerHTML).to.equal('<!-- test --><div>Hello</div>');
- expect(getLog()).to.deep.equal([]);
- clearLog();
-
- return resolve(() => <div>Hello</div>).then(() => {
- rerender();
- expect(scratch.innerHTML).to.equal('<!-- test --><div>Hello</div>');
- expect(getLog()).to.deep.equal([]);
- clearLog();
- });
- });
-
  it('should properly attach event listeners when suspending while hydrating', () => {
  scratch.innerHTML = '<div>Hello</div><div>World</div>';
  clearLog();

compat/test/browser/suspense.test.js

@@ -299,6 +299,25 @@ describe('suspense', () => {
  });
  });
 
+ it('should not duplicate DOM when suspending while rendering', () => {
+ scratch.innerHTML = '<div>Hello</div>';
+
+ const [Lazy, resolve] = createLazy();
+ render(
+ <Suspense>
+ <Lazy />
+ </Suspense>,
+ scratch
+ );
+ rerender(); // Flush rerender queue to mimic what preact will really do
+ expect(scratch.innerHTML).to.equal('');
+
+ return resolve(() => <div>Hello</div>).then(() => {
+ rerender();
+ expect(scratch.innerHTML).to.equal('<div>Hello</div>');
+ });
+ });
+
  it('should suspend when a promise is thrown', () => {
  class ClassWrapper extends Component {
  render(props) {

src/diff/index.js

@@ -275,7 +275,7 @@ export function diff(
  if (isHydrating || excessDomChildren != null) {
  newVNode._flags |= isHydrating
  ? MODE_HYDRATE | MODE_SUSPENDED
- : MODE_HYDRATE;
+ : MODE_SUSPENDED;
 
  while (oldDom && oldDom.nodeType === 8 && oldDom.nextSibling) {
  oldDom = oldDom.nextSibling;