Clean up unreferenced topic files after successful remote-config refresh

[tonidero]

Motivation

TopicFetcher writes a new file every time the manifest's blob_ref rotates, but never deletes the previous one. Without cleanup, the on-disk cache at noBackupFilesDir/RevenueCat/topics/... grows unboundedly across backend rotations. This PR adds a one-shot disk-hygiene pass that runs at the end of each fully successful remote-config refresh.

Description

• suspend fun TopicFetcher.cleanupUnreferencedTopics(referenced: Map<Topic, Set<String>>) — wraps the disk walk in withContext(Dispatchers.IO), iterates Topic.values(), lists each topic's directory, and deletes files whose name isn't in the keep-set for that topic. Skips files prefixed with rc_topic_ (the createTempFile prefix, now extracted as a TEMP_PREFIX constant) so a concurrent in-flight download isn't clobbered.
• RemoteConfigManager.refresh — builds the reference set as the union of every blob ref in the new manifest (across all variants, not just DEFAULT) and triggers cleanup at the right moment, all within the existing suspend coroutine flow:
  • When sources is empty or no DEFAULT-variant tasks remain → cleanup runs immediately (fetchError = null short-circuit).
  • When downloads dispatch → after the async/awaitAll fan-out, cleanup is awaited only if every fetch returned null (no error). Partial-failure refreshes leave the cache untouched.

Confirmed semantics:

• Reference set spans all variants in the new manifest (forward-compatible if non-DEFAULT variants ever start being cached).
• Topics in the SDK's Topic enum but absent from the new manifest get all their cached files wiped (reference-set = ∅).
• Cleanup runs only when every download in the refresh succeeded.

Tests

runTest for both:

• 5 new TopicFetcherTest cases: delete unreferenced / wipe topic absent from set / no-op when root missing / preserve rc_topic_*.tmp / mixed keep+delete.
• 5 new RemoteConfigManagerTest cases (with coEvery { topicFetcher.cleanupUnreferencedTopics(any()) } returns Unit + coVerify): cleanup with all-variant refs / cleanup on empty sources & empty topics / no cleanup on fetcher error / no cleanup on backend error.

All changes are internal; no public API surface change.

Stack

• ⬇ Add network scaffolding for remote config endpoint: Add network scaffolding for remote config endpoint #3435
• ⬇ Add RemoteConfigManager and TopicFetcher: Add RemoteConfigManager and TopicFetcher #3437
• This PR: Clean up unreferenced topic files after successful remote-config refresh #3439

Checklist

• Unit tests
• Follow-up issues for purchases-ios / hybrids (deferred)

---

Note

Medium Risk
Adds automatic deletion of on-disk topic files after successful remote-config refresh; mistakes in reference calculation or deletion logic could remove still-needed cached data, though it is guarded to run only on fully successful refreshes and has test coverage.

Overview
After a fully successful remote-config refresh, the SDK now performs a one-shot cleanup pass to delete unreferenced cached topic blob files under noBackupFilesDir/RevenueCat/topics, preventing unbounded growth when blob_refs rotate.

RemoteConfigManager builds a per-topic keep-set from all manifest entryIds’ blob_refs and calls TopicFetcher.cleanupUnreferencedTopics() only when refresh completes with no errors (and caching conditions are met). TopicFetcher implements the disk walk/deletion, skips in-flight temp files via a shared rc_topic_ prefix constant, and adds unit tests covering the new cleanup behavior and its failure/no-op cases.

^{Reviewed by Cursor Bugbot for commit 9503c36. Bugbot is set up for automated code reviews on this repo. Configure here.}

[tonidero]

• Use product_entitlement_mapping topic blob for offline entitlements when remote config enabled #3455
• Wire RemoteConfigManager refresh on first foreground and identity changes (off by default) #3450
• Fall back across blob sources when topic downloads fail #3466
• Select blob source by priority and weighted random #3458
• Clean up unreferenced topic files after successful remote-config refresh #3439 👈 (View in Graphite)
• Cache remote config response in memory with TTL and persist to disk #3457
• Add RemoteConfigManager and TopicFetcher #3437
• Add network scaffolding for remote config endpoint #3435
• main

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[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.62%. Comparing base (b83a198) to head (e1dac4b).

Files with missing lines	Patch %	Lines
...ecat/purchases/common/remoteconfig/TopicFetcher.kt	70.00%	2 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3439      +/-   ##
==========================================
- Coverage   79.63%   79.62%   -0.01%     
==========================================
  Files         368      368              
  Lines       14829    14853      +24     
  Branches     2028     2037       +9     
==========================================
+ Hits        11809    11827      +18     
- Misses       2200     2202       +2     
- Partials      820      824       +4     

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[emerge-tools]

📸 Snapshot Test

591 unchanged

Name	Added	Removed	Modified	Renamed	Unchanged	Errored	Approval
TestPurchasesUIAndroidCompatibility com.revenuecat.testpurchasesuiandroidcompatibility	0	0	0	0	334	0	N/A
TestPurchasesUIAndroidCompatibility Paparazzi com.revenuecat.testpurchasesuiandroidcompatibility.paparazzi	0	0	0	0	257	0	N/A

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[ajpallares]

Looking good! I do have one concern that we may want to address before merging

[ajpallares]

Great progress!! A couple of nits, but no blockers. Good job!

[ajpallares]

Seems like since Kotlin 1.9, entries is the recommended replacement for values()

Suggested change

	Topic.values().forEach topics@{ topic ->
	Topic.entries.forEach topics@{ topic ->

[tonidero]

Indeed... but that requires opting in to an experimental flag because we are supporting older kotlin versions... So I think it's better to keep as is :)

[ajpallares]

Agreed!

[ajpallares]

If we ever remove a case from the Topic enum, we would end up with an unused directory here. I guess that's fine for now

[tonidero]

That's a valid point... Could be a further cleanup we do but I won't block the PR because of this. Good catch though!

[tonidero]

Merge activity

• May 12, 2:06 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• May 12, 2:07 PM UTC: Graphite couldn't merge this PR because it failed for an unknown reason (This repository has GitHub's merge queue enabled. Please configure the GitHub merge queue integration in Graphite settings.).