next.js

ed3cb83c - next/script: make `onLoad` concurrent rendering resilient (#40191)

next/script: make `onLoad` concurrent rendering resilient (#40191) Another step toward fixing #40025. Multiple `next/script` components with the same `src` may exist in the Next.js app. So the `loadScript` function will always attach the `onLoad` handler to the `loadingPromise` every time it executes. However, with strict mode (or wrapped inside the `<OffScreen />` component), the `useEffect` could execute more than once for the same `next/script` component, thus the `loadScript` for each `next/script` component could execute more than once (and `onLoad` to be attached more than once), results in `onLoad` fires more than once. The PR makes sure that for every `next/script` component mounted, the `loadScript` will always be executed only once for each of them. The corresponding `onload fires correctly` integration test case is also updated to run in dev mode. ## Bug - [x] Related issues linked using `fixes #number` - [x] Integration tests added - [ ] Errors have helpful link attached, see `contributing.md`