[Internal API only] Delete non-awaited form of act (#26339)

**This commit only affects the internal version of `act` that we use in
this repo. The public `act` API is unaffected, for now.**

We should always await the result of an `act` call so that any work
queued in a microtask has a chance to flush. Neglecting to do this can
cause us to miss bugs when testing React behavior.

I codemodded all the existing `act` callers in previous PRs.

packages/jest-react/src/internalAct.js

@@ -22,7 +22,7 @@ import enqueueTask from 'shared/enqueueTask';
 
 let actingUpdatesScopeDepth = 0;
 
-export function act<T>(scope: () => Thenable<T> | T): Thenable<T> {
+export function act<T>(scope: () => Thenable<T>): Thenable<T> {
  if (Scheduler.unstable_flushUntilNextPaint === undefined) {
  throw Error(
  'This version of `act` requires a special mock build of Scheduler.',
@@ -64,58 +64,45 @@ export function act<T>(scope: () => Thenable<T> | T): Thenable<T> {
  }
  };
 
- // TODO: This would be way simpler if 1) we required a promise to be
- // returned and 2) we could use async/await. Since it's only our used in
- // our test suite, we should be able to.
+ // TODO: This would be way simpler if we could use async/await. Move this
+ // function to the internal-test-utils package.
  try {
  const result = scope();
  if (
- typeof result === 'object' &&
- result !== null &&
- // $FlowFixMe[method-unbinding]
- typeof result.then === 'function'
+ typeof result !== 'object' ||
+ result === null ||
+ typeof (result: any).then !== 'function'
  ) {
- const thenableResult: Thenable<T> = (result: any);
- return {
- then(resolve: T => mixed, reject: mixed => mixed) {
- thenableResult.then(
- returnValue => {
- flushActWork(
- () => {
- unwind();
- resolve(returnValue);
- },
- error => {
- unwind();
- reject(error);
- },
- );
- },
- error => {
- unwind();
- reject(error);
- },
- );
- },
- };
- } else {
- const returnValue: T = (result: any);
- try {
- // TODO: Let's not support non-async scopes at all in our tests. Need to
- // migrate existing tests.
- let didFlushWork;
- do {
- didFlushWork = Scheduler.unstable_flushAllWithoutAsserting();
- } while (didFlushWork);
- return {
- then(resolve: T => mixed, reject: mixed => mixed) {
- resolve(returnValue);
- },
- };
- } finally {
- unwind();
- }
+ throw new Error(
+ 'The internal version of `act` used in the React repo must be passed ' +
+ "an async function, even if doesn't await anything. This is a " +
+ 'temporary limitation that will soon be fixed.',
+ );
  }
+ const thenableResult: Thenable<T> = (result: any);
+
+ return {
+ then(resolve: T => mixed, reject: mixed => mixed) {
+ thenableResult.then(
+ returnValue => {
+ flushActWork(
+ () => {
+ unwind();
+ resolve(returnValue);
+ },
+ error => {
+ unwind();
+ reject(error);
+ },
+ );
+ },
+ error => {
+ unwind();
+ reject(error);
+ },
+ );
+ },
+ };
  } catch (error) {
  unwind();
  throw error;