Propagate adapter preferred regions

[timneutkens]

What?

Propagate edge runtime preferredRegion metadata into adapter outputs and add adapter-config coverage for an edge app route.

Why?

Adapters need access to preferred region metadata from edge outputs when generating provider-specific deployment output.

How?

Copy edge function regions into output.config.preferredRegion and assert the adapter build-complete output for a fixture route with preferredRegion set to cdg1.

Verification

• pnpm --filter=next build
• NEXT_TEST_PREFER_OFFLINE=1 pnpm test-start-webpack test/production/adapter-config/adapter-config.test.ts

[github-actions]

Failing test suites

Commit: 1b7e45a | About building and testing Next.js

pnpm test-dev test/development/app-dir/instant-navs-devtools/instant-navs-devtools.test.ts (job)

• instant-nav-panel > SPA captures > should re-arm capture and return to awaiting navigation after Continue Rendering from SPA state (DD)

Expand output

● instant-nav-panel › SPA captures › should re-arm capture and return to awaiting navigation after Continue Rendering from SPA state

expect(received).toMatch(expected)

Expected pattern: /next-instant-navigation-testing=[^;]+/
Received string:  ""

  25 |     await retry(async () => {
  26 |       const cookie = await browser.eval(() => document.cookie)
> 27 |       expect(cookie).toMatch(/next-instant-navigation-testing=[^;]+/)
     |                      ^
  28 |     })
  29 |   }
  30 |

  at toMatch (development/app-dir/instant-navs-devtools/instant-navs-devtools.test.ts:27:22)
  at retry (lib/next-test-utils.ts:867:14)
  at waitForInstantModeCookie (development/app-dir/instant-navs-devtools/instant-navs-devtools.test.ts:25:5)
  at Object.<anonymous> (development/app-dir/instant-navs-devtools/instant-navs-devtools.test.ts:542:7)

Other failing CI jobs

• test cargo unit / build

[github-actions]

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Commit: 1b7e45a
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[vercel]

Additional Suggestion:

The app/preferred-region/route.ts fixture with dynamic = 'force-dynamic' and runtime = 'edge' is not excluded from the output: 'export' test build, causing it to fail.