ensure null loading boundaries still render a Suspense boundary

[ztanner]

This ensures that even if a loading.js returns null, that we still render a Suspense boundary, as it's perfectly valid to have an empty fallback.

This was accidentally lost in #62346 -- this brings back the hasLoading prop which will check the loading module itself (rather than the ReactNode) for truthiness, and I've added a test to avoid another regression.

Closes NEXT-2936

[ztanner]

• ensure null loading boundaries still render a Suspense boundary #63726 👈
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[ijjk]

Failing test suites

Commit: 20cb3c3

pnpm test-start test/production/graceful-shutdown/index.test.ts

• Graceful Shutdown > production (standalone mode) > should not accept new requests during shutdown cleanup > when there is no activity

Expand output

● Graceful Shutdown › production (standalone mode) › should not accept new requests during shutdown cleanup › when there is no activity

expect(received).toBe(expected) // Object.is equality

Expected: 0
Received: null

  228 |         // App finally shuts down
  229 |         await appKilledPromise
> 230 |         expect(app.exitCode).toBe(0)
      |                              ^
  231 |       })
  232 |     })
  233 |   }

  at Object.toBe (production/graceful-shutdown/index.test.ts:230:30)

Read more about building and testing Next.js in contributing.md.

pnpm test-dev test/e2e/app-dir/navigation/navigation.test.ts

• app dir - navigation > scroll restoration > should restore original scroll position when navigating back

Expand output

● app dir - navigation › scroll restoration › should restore original scroll position when navigating back

page.waitForSelector: Timeout 60000ms exceeded.
Call log:
  - waiting for locator('#back-button')

  421 |     return this.chain(() => {
  422 |       return page
> 423 |         .waitForSelector(selector, { timeout, state: 'attached' })
      |          ^
  424 |         .then(async (el) => {
  425 |           // it seems selenium waits longer and tests rely on this behavior
  426 |           // so we wait for the load event fire before returning

  at waitForSelector (lib/browsers/playwright.ts:423:10)

Read more about building and testing Next.js in contributing.md.

[ijjk]

Stats from current PR

Default Build (Increase detected ⚠️)

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
buildDuration	14s	13.8s	N/A
buildDurationCached	7.5s	6.2s	N/A
nodeModulesSize	198 MB	198 MB	⚠️ +1.43 kB
nextStartRea..uration (ms)	400ms	412ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
2453-HASH.js gzip	30.8 kB	30.8 kB	N/A
3304.HASH.js gzip	181 B	181 B	✓
3f784ff6-HASH.js gzip	53.7 kB	53.7 kB	✓
8299-HASH.js gzip	5.04 kB	5.04 kB	N/A
framework-HASH.js gzip	45.2 kB	45.2 kB	✓
main-app-HASH.js gzip	242 B	239 B	N/A
main-HASH.js gzip	32.2 kB	32.2 kB	N/A
webpack-HASH.js gzip	1.68 kB	1.68 kB	N/A
Overall change	99 kB	99 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
_app-HASH.js gzip	196 B	197 B	N/A
_error-HASH.js gzip	184 B	184 B	✓
amp-HASH.js gzip	505 B	505 B	✓
css-HASH.js gzip	324 B	325 B	N/A
dynamic-HASH.js gzip	2.5 kB	2.5 kB	N/A
edge-ssr-HASH.js gzip	258 B	258 B	✓
head-HASH.js gzip	352 B	352 B	✓
hooks-HASH.js gzip	370 B	371 B	N/A
image-HASH.js gzip	4.21 kB	4.21 kB	✓
index-HASH.js gzip	259 B	259 B	✓
link-HASH.js gzip	2.67 kB	2.67 kB	N/A
routerDirect..HASH.js gzip	314 B	312 B	N/A
script-HASH.js gzip	386 B	386 B	✓
withRouter-HASH.js gzip	309 B	309 B	✓
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	6.57 kB	6.57 kB	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
_buildManifest.js gzip	481 B	484 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
index.html gzip	529 B	529 B	✓
link.html gzip	541 B	541 B	✓
withRouter.html gzip	524 B	523 B	N/A
Overall change	1.07 kB	1.07 kB	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
edge-ssr.js gzip	95.3 kB	95.3 kB	N/A
page.js gzip	3.04 kB	3.04 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
middleware-b..fest.js gzip	625 B	625 B	✓
middleware-r..fest.js gzip	151 B	151 B	✓
middleware.js gzip	25.5 kB	25.5 kB	N/A
edge-runtime..pack.js gzip	839 B	839 B	✓
Overall change	1.61 kB	1.61 kB	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
app-page-exp...dev.js gzip	170 kB	170 kB	✓
app-page-exp..prod.js gzip	96.8 kB	96.8 kB	✓
app-page-tur..prod.js gzip	98.5 kB	98.5 kB	✓
app-page-tur..prod.js gzip	92.8 kB	92.8 kB	✓
app-page.run...dev.js gzip	144 kB	144 kB	✓
app-page.run..prod.js gzip	91.3 kB	91.3 kB	✓
app-route-ex...dev.js gzip	21.3 kB	21.3 kB	✓
app-route-ex..prod.js gzip	15 kB	15 kB	✓
app-route-tu..prod.js gzip	15 kB	15 kB	✓
app-route-tu..prod.js gzip	14.8 kB	14.8 kB	✓
app-route.ru...dev.js gzip	21 kB	21 kB	✓
app-route.ru..prod.js gzip	14.8 kB	14.8 kB	✓
pages-api-tu..prod.js gzip	9.55 kB	9.55 kB	✓
pages-api.ru...dev.js gzip	9.82 kB	9.82 kB	✓
pages-api.ru..prod.js gzip	9.55 kB	9.55 kB	✓
pages-turbo...prod.js gzip	22.5 kB	22.5 kB	✓
pages.runtim...dev.js gzip	23.1 kB	23.1 kB	✓
pages.runtim..prod.js gzip	22.4 kB	22.4 kB	✓
server.runti..prod.js gzip	50.9 kB	50.9 kB	✓
Overall change	943 kB	943 kB	✓

build cache Overall increase ⚠️

	vercel/next.js canary	vercel/next.js 03-26-ensure_null_loading_boundaries_still_render_a_Suspense_boundary	Change
0.pack gzip	1.56 MB	1.56 MB	N/A
index.pack gzip	105 kB	106 kB	⚠️ +973 B
Overall change	105 kB	106 kB	⚠️ +973 B

Diff details

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Commit: 20cb3c3