fix(cdn): retry manifest fetch after transient download failure#2262
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_lastUpdatedAt was advanced when lastUpdateTime.json reported a newer timestamp, even if the subsequent manifest download failed. That made later refresh checks skip the update until the CDN published again, leaving CDN-backed apps on stale definitions for the rest of the session. Only commit the remote timestamp after a manifest is successfully fetched and cached. Extract cdnShouldFetchManifest helpers for unit testing. Co-authored-by: Sharjeel Yunus <sharjeelyunus@users.noreply.github.com>
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Description
Fixes a CDN freshness bug where a successful
lastUpdateTime.jsoncheck could permanently skip manifest re-download for the rest of the app session if the actual manifest fetch failed.Bug and impact
Trigger: A CDN-backed app checks for updates;
lastUpdateTime.jsonreports a newerlastUpdatedAt, but the manifest download fails (network timeout, 5xx, decrypt error, etc.).Impact:
_lastUpdatedAtwas advanced before the manifest was successfully fetched and cached. Subsequent refresh checks saw matching timestamps and skipped the download until the CDN published another update. Apps could remain on stale screens, scripts, and translations for the entire session.Root cause
_shouldFetchManifest()mutated_lastUpdatedAtto the remote timestamp as soon aslastUpdateTime.jsonwas read, before_fetchManifest()completed. A failed download left the in-memory timestamp advanced with no corresponding cached manifest.Fix
_shouldFetchManifest()with_evaluateManifestFreshness()that returns{shouldFetch, remoteLastUpdatedAt}without mutating_lastUpdatedAt._commitRemoteLastUpdatedAt().cdnShouldFetchManifest/cdnIsIncomingManifestNewerhelpers for unit testing.How to Test
modules/ensemble, runflutter test test/cdn_provider_test.dart.Duplicate check
listenForChangesdedup crash; different code path.cursor/critical-bug-remediation-c136) — CDN background lifecycle deferral for artifact refresh UI; different root cause (i18n refresh ordering on pause/resume, not failed-fetch retry)._lastUpdatedAtcommit on failed download._lastUpdatedAtadvancement on failed manifest fetch.Type of Change