DX: fix error overlay flash

[huozhi]

What

Skipping module build error and module not found error in onUnhandledError handler from pages router dev overlay, to avoid the build error being caught twice by error overlay in both unhandled error and build error type. The unhandled error is slightly eariler than build error, which causes the flash. We skipped it to avoid display same duplicated errors.

Why

This change fixes a flashing UX on error overlay when build error occurred, it will go from a white background with red text to a source panel with actual code where triggered build error, such as synatx error. I recodered two videos to show them properly. Since it happens too fast, hard to address them with test, more like fixing a minor frustration in the UI.

After

after-stable.mp4

Before

before-flashing.mp4

Closes NEXT-2403
Closes NEXT-2145

[ijjk]

Stats from current PR

Default Build

General Overall increase ⚠️

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
buildDuration	13.5s	13.6s	N/A
buildDurationCached	6.9s	6s	N/A
nodeModulesSize	196 MB	196 MB	⚠️ +338 B
nextStartRea..uration (ms)	448ms	465ms	N/A

Client Bundles (main, webpack)

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
3f784ff6-HASH.js gzip	53.4 kB	53.4 kB	N/A
423.HASH.js gzip	185 B	181 B	N/A
68-HASH.js gzip	29.5 kB	29.5 kB	N/A
framework-HASH.js gzip	45.2 kB	45.2 kB	✓
main-app-HASH.js gzip	238 B	240 B	N/A
main-HASH.js gzip	31.8 kB	31.8 kB	N/A
webpack-HASH.js gzip	1.7 kB	1.7 kB	✓
Overall change	46.9 kB	46.9 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
polyfills-HASH.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
_app-HASH.js gzip	194 B	195 B	N/A
_error-HASH.js gzip	182 B	181 B	N/A
amp-HASH.js gzip	502 B	501 B	N/A
css-HASH.js gzip	320 B	322 B	N/A
dynamic-HASH.js gzip	2.5 kB	2.5 kB	N/A
edge-ssr-HASH.js gzip	255 B	256 B	N/A
head-HASH.js gzip	350 B	349 B	N/A
hooks-HASH.js gzip	368 B	369 B	N/A
image-HASH.js gzip	4.19 kB	4.18 kB	N/A
index-HASH.js gzip	257 B	256 B	N/A
link-HASH.js gzip	2.67 kB	2.67 kB	N/A
routerDirect..HASH.js gzip	310 B	311 B	N/A
script-HASH.js gzip	384 B	383 B	N/A
withRouter-HASH.js gzip	306 B	308 B	N/A
1afbb74e6ecf..834.css gzip	106 B	106 B	✓
Overall change	106 B	106 B	✓

Client Build Manifests

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
_buildManifest.js gzip	483 B	485 B	N/A
Overall change	0 B	0 B	✓

Rendered Page Sizes

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
index.html gzip	526 B	526 B	✓
link.html gzip	541 B	539 B	N/A
withRouter.html gzip	521 B	521 B	✓
Overall change	1.05 kB	1.05 kB	✓

Edge SSR bundle Size

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
edge-ssr.js gzip	94 kB	94 kB	N/A
page.js gzip	149 kB	149 kB	N/A
Overall change	0 B	0 B	✓

Middleware size

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
middleware-b..fest.js gzip	621 B	623 B	N/A
middleware-r..fest.js gzip	151 B	149 B	N/A
middleware.js gzip	47.4 kB	47.4 kB	✓
edge-runtime..pack.js gzip	1.94 kB	1.94 kB	✓
Overall change	49.3 kB	49.3 kB	✓

Next Runtimes

	vercel/next.js canary	vercel/next.js fix/error-overlay-flash	Change
app-page-exp...dev.js gzip	166 kB	166 kB	✓
app-page-exp..prod.js gzip	95.1 kB	95.1 kB	✓
app-page-tur..prod.js gzip	96.9 kB	96.9 kB	✓
app-page-tur..prod.js gzip	91.5 kB	91.5 kB	✓
app-page.run...dev.js gzip	135 kB	135 kB	✓
app-page.run..prod.js gzip	90 kB	90 kB	✓
app-route-ex...dev.js gzip	22 kB	22 kB	✓
app-route-ex..prod.js gzip	14.8 kB	14.8 kB	✓
app-route-tu..prod.js gzip	14.8 kB	14.8 kB	✓
app-route-tu..prod.js gzip	14.6 kB	14.6 kB	✓
app-route.ru...dev.js gzip	21.7 kB	21.7 kB	✓
app-route.ru..prod.js gzip	14.6 kB	14.6 kB	✓
pages-api-tu..prod.js gzip	9.43 kB	9.43 kB	✓
pages-api.ru...dev.js gzip	9.7 kB	9.7 kB	✓
pages-api.ru..prod.js gzip	9.43 kB	9.43 kB	✓
pages-turbo...prod.js gzip	22 kB	22 kB	✓
pages.runtim...dev.js gzip	22.7 kB	22.7 kB	✓
pages.runtim..prod.js gzip	22 kB	22 kB	✓
server.runti..prod.js gzip	49.7 kB	49.7 kB	✓
Overall change	922 kB	922 kB	✓

Commit: 661606c

[ijjk]

Tests Passed