fix(currency): a background rate refresh was breaking the render that started it - #814
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… started it Production logs, repeatedly: Error: Page changed from static to dynamic at runtime /discover, reason: revalidate: 0 fetch https://api.coingecko.com/api/v3/simple/price /discover getCachedRateSnapshot is the "never wait on a third party to paint" path: it returns a snapshot or null and refreshes in the background, and nothing awaits that refresh. But not-awaited is not the same as not-attributed. fetchUpstream uses `cache: 'no-store'`, Next tracks every fetch started during a render, and starting it synchronously put it inside the render's async context — so Next reclassified a statically prerendered route and the render failed. A macrotask boundary moves the fetch out of that context. The refresh still happens, on the same schedule; only its attribution changes. Deliberately not `after()` from next/server: this module is called from plain server code as well as from requests and must not require a request scope. Also warms a cold process. When there was no snapshot at all — every deploy — the function returned null and scheduled NOTHING, so amounts stayed in BTC until some other caller happened to await getRateSnapshot(). Safe to schedule from here now that a refresh no longer contaminates the render that triggers it. Found while chasing a timeline that renders its skeleton and never resolves. Whether this is that bug's cause is NOT established — the logged failures name /discover — but it is a real render-breaking fault on shared currency code, it fires on exactly the cold-start window where the timeline symptom is worst, and the timing is worth removing from the picture either way. Proven by mutation: restoring the synchronous `void refresh()` fails three of the four timing tests. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_012dpTLxh5GJWeWTF1UEvcD5
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Production logs, repeatedly:
getCachedRateSnapshotis the "never wait on a third party to paint" path: it returns a snapshot or null and refreshes in the background, and nothing awaits that refresh. But not-awaited is not the same as not-attributed.fetchUpstreamusescache: 'no-store', Next tracks every fetch started during a render, and starting it synchronously put it inside the render's async context — so Next reclassified a statically prerendered route and the render failed.A macrotask boundary moves the fetch out of that context. The refresh still happens, on the same schedule; only its attribution changes. Deliberately not
after()fromnext/server: this module is called from plain server code as well as from requests, and must not require a request scope.Also warms a cold process. With no snapshot at all — every deploy — the function returned null and scheduled nothing, so amounts stayed in BTC until some other caller happened to await
getRateSnapshot(). Safe to schedule from here now that a refresh no longer contaminates the render that triggers it.Honesty about scope
Found while chasing a timeline that renders its skeleton and never resolves. Whether this is that bug's cause is not established — the logged failures name
/discover. But it is a real render-breaking fault in shared currency code, it fires on exactly the cold-start window where the timeline symptom is worst, and it is worth removing from the picture either way.Proven by mutation: restoring the synchronous
void refresh()fails three of the four timing tests.🤖 Generated with Claude Code
https://claude.ai/code/session_012dpTLxh5GJWeWTF1UEvcD5