feat(workflows): serve stale workflow detail while revalidating#6961
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Port of purchases-android#3540. getWorkflow now uses stale-while-revalidate like OfferingsManager: a stale-but-present detail is served immediately and the cache is refreshed in the background (a success updates the cache, a failure is logged and swallowed). Prefetch opts out via staleWhileRevalidate: false, so it keeps forcing a fresh fetch and persisting its envelope instead of serving a stale value. The background refresh captures its generation guard before serving the cached value, so a clearCache() (login/logout) racing the serve still drops the write, keeping the previous user's detail out of the new user's cache. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
vegaro
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I think this makes sense. We need to do the same for getWorkflows right? Otherwise it blocks on a stale cache
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purchases-androidand hybrids (this ports purchases-android#3540)Motivation
A workflow whose cached detail went stale currently blocks on a backend round-trip before the paywall can render. This brings the workflow detail fetch in line with how
OfferingsManageralready serves offerings: serve the cached value instantly and refresh in the background.Description
Port of purchases-android#3540 (detail only).
WorkflowManager.getWorkflownow uses stale-while-revalidate:flowchart TD A([getWorkflow]) --> B{cached entry present?} B -->|no| MISS["block on backend fetch,<br/>deliver result to caller"] B -->|yes| C{still fresh?} C -->|yes| FRESH["serve cached, no network"] C -->|stale| SWR{staleWhileRevalidate?} SWR -->|"false (prefetch)"| MISS SWR -->|"true (on-demand)"| STALE["capture generation G,<br/>serve stale value to caller,<br/>then refresh in background<br/>(failures logged, not delivered)"] MISS --> WRITE["guarded cache write"] STALE --> WRITE WRITE --> G{generation still G?} G -->|yes| OK["update cache + warm assets"] G -->|"no: clearCache on login/logout"| DROP["drop write,<br/>keeps prev user's detail out"]Prefetch passes
staleWhileRevalidate: false, so it keeps forcing a fresh fetch and persisting its envelope rather than serving and persisting a stale value.The background refresh captures its generation guard before serving, so a
clearCache()(login/logout) racing the serve still drops the write, keeping the previous user's detail out of the new user's cache (consistent with #6944).The workflows list is intentionally left as is: it already rides offerings' stale-while-revalidate, and the one place it blocks (
deliverEnsuringWorkflowsListon the fresh-offerings path) exists on purpose to guaranteecachedWorkflowId(forOfferingId:)resolves right aftergetOfferings.AI session context
Metadata
facu/workflow-detail-swr(off the fix(workflows): Don't leak the previous user's workflows after a login or logout #6944 merge commit)Goal
Give the workflow detail fetch the same stale-while-revalidate behavior offerings already have, mirroring purchases-android#3540. Detail only; the workflows list is explicitly out of scope.
Initial Prompt
The human asked whether iOS should serve-cache-then-fetch for workflows like Android #3540, framed as "do the same as offerings for both list and details". After comparing the current iOS code (offerings already SWR; detail blocks on stale; list blocks but rides offerings' SWR), the agent recommended porting #3540 for the detail and leaving the list alone. The human agreed ("let's port that then"), then asked to send the change to Codex for review.
Agent Contribution
staleWhileRevalidate: Bool = truetogetWorkflow; extracted the backend-fetch + cache + warm-up body into a privatefetchAndCacheWorkflowshared by the blocking path and the background refresh.false.PaywallsStrings.error_refreshing_workflowfor the swallowed background-refresh failure.truereds the persist-fresh test).Human Decisions
debug-view-locale- ios-17 #3540 for the detail; do NOT make the workflows list SWR (it already rides offerings' SWR, and the one blocking path guarantees workflow-id resolution right aftergetOfferings).Codex Review and Resolution
Task {}, opening an async window for a cross-user leak. That mechanism is incorrect: the helper is called synchronously, noTask, noawait.completion()between them. Fix applied: capture the generation before serving, so the background write binds to the serve-time generation (same guarantee the blocking path and fix(workflows): Don't leak the previous user's workflows after a login or logout #6944 have). The residual sub-statement race is the same lock-free read window fix(workflows): Don't leak the previous user's workflows after a login or logout #6944 accepted by design and is not chased here.WorkflowsAPI's callback cache). Added two coverage tests Codex suggested.Files / Symbols Touched
Sources/Purchasing/WorkflowManager.swift-getWorkflow(..., staleWhileRevalidate:), newfetchAndCacheWorkflow, prefetch opt-out.Sources/Logging/Strings/PaywallsStrings.swift-error_refreshing_workflow.Tests/UnitTests/Purchasing/WorkflowManagerTests.swift- 6 new tests.Validation
xcodebuild test(iPhone 15 sim) forWorkflowManagerTests(48),PurchasesWorkflowTests(42),WorkflowsCacheTests: 91 passing, 0 failures.swiftlinton changed files: clean.Validation Gaps
Review Focus
getWorkflow's generation is captured beforecompletionon the SWR path; the background refresh delivers no result to the caller.staleWhileRevalidate: false(a stale prefetch must fetch and persist fresh, not serve stale).WorkflowManageris internal and the new parameter is optional/defaulted, so noswiftinterfacechange.Non-goals / Out of Scope