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fix(nextjs): Don't report Next.js prerender control flow errors - #23691
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chargome merged 3 commits intoAug 31, 2026
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Next.js throws a set of errors to steer rendering rather than to signal a failure. Its `unstable_rethrow` defines the contract any code wrapping user land in a try/catch has to honor, but the Sentry wrappers only recognized redirects and not-founds. Everything else - most visibly the `HANGING_PROMISE_REJECTION` that Cache Components produces for uncached `fetch()` during a prerender - was reported as an error. Filtering was also coupled to `getActiveSpan()` being truthy, so with no active span nothing was filtered at all, including redirects and not-founds. Fixes#23592 Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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chargome
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The hanging-promise e2e test concluded "no error was captured" after a fixed 5s sleep, which is flake-prone in both directions: a late event could be missed, and every run paid the full 5s. It now requests a route that captures an error tagged with a token unique to the run. The token guarantees a cache miss, the request happens strictly after the prefetch, and the SDK flushes per request - so once that error arrives, any error the prefetch captured must have arrived too. It doubles as a positive control that errors flow at all. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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`withServerActionInstrumentation` catches user land errors like the other wrappers, so it honors the same `unstable_rethrow` contract. Next.js only throws these from a prerender scope and server actions run in a request scope, so this is not reachable today - it is consistency and a guard against Next.js routing them differently later. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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chargome
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Next.js uses some thrown errors as control flow, not as real failures.
unstable_rethrowlists them, and any code that catches user errors is supposed to ignore them. We only ignored redirects and not-founds, so we reportedHANGING_PROMISE_REJECTION,NEXT_PRERENDER_INTERRUPTED,DYNAMIC_SERVER_USAGEandBAILOUT_TO_CLIENT_SIDE_RENDERINGas errors.This shows up most with Cache Components. An uncached
fetch()during a prerender never actually runs — Next returns a promise that never resolves, then rejects it when the prerender is aborted. React throws that rejection away, but our server component wrapper caught it and sent it to Sentry.There was also a second problem: since #18408 the filtering only ran if there was an active span. Without one, nothing was filtered, so even plain
redirect()andnotFound()got reported. Both wrappers now filter regardless of whether a span exists.closes#23592