Fix cancellation bug and build backup Phase 1 policy in Kotlin Multiplatform lib
Session from pi-coding-sessions on Hugging Face by championswimmer · MIT · condensed by Coders Talk
Fix a coroutine-cancellation swallowing bug in BackupTransportRegistry.providerInfo(), then implement Phase 1 of the backup transports rollout plan (provider capability metadata and automatic restore policy), and finally look for a KMP file picker library for local backup.
- +0Prompt · +0providerInfo() uses runCatching around transport.isAvailable(), which swallows CancellationException. Use explicit try/catch that rethrows CancellationException and treats other failures as isAvailable=false.
- +0mAgent did · +0mLocated BackupTransportRegistry.kt, replaced runCatching with explicit try/catch rethrowing CancellationException, updated tests, fixed the CancellationException import to the multiplatform kotlin.coroutines.cancellation variant, and ran :sharedLib:jvmTest for the affected test class until it passed.
- +1mAgent did · +1mCommitted the cancellation fix ("Handle cancellation in provider info") and pushed the branch upstream to origin/arnav/mutli-backup-transports.
- +2mPrompt · +2mNow implement phase 1 of .agents/plans/13-backup-transports-rollout-plan.md.
- +2mAgent did · +2mRead the rollout plan, BackupProvider/BackupService/BackupTransportRegistry and existing storage/DI code, then added BackupProviderCapabilityRules, BackupPreferences (with BackupProviderMetadata and BackupRemoteMarker), and AutomaticRestorePolicy with a decision enum, wired it into BackupService, wrote/iterated on AutomaticRestorePolicyTest and BackupServiceTest, updated the plan's progress checklist, and refreshed the sharedLib ABI dumps (checkLegacyAbi/updateLegacyAbi) until jvmTest passed.
- Break · 1h 05m away, not counted
- +9mPrompt · +9mCommit and push.
- +9mAgent did · +9mCommitted Phase 1 changes across 9 files as "Implement backup Phase 1 policy and metadata" and pushed to origin/arnav/mutli-backup-transports.
- Break · 48m away, not counted
- +9mPrompt · +9mFor the local file backup provider, search whether there's a KMP-friendly file/folder picker library, or native KMP support for picking a save location (use ddg or perplexity MCP to search).
- +10mFail · +10mThe duckduckgo MCP search tool errored out repeatedly ("Retrying exceeded the maxAttempts"), no perplexity MCP tool was available, and fallback attempts using curl/python against DuckDuckGo HTML also failed to produce usable results, so the file-picker research never completed.
- +11mOutcome · +11mTwo commits shipped and pushed (cancellation fix + Phase 1 policy/metadata, 9 files, 524 insertions), jvmTest green throughout; file picker library research left unresolved after MCP/search tooling failures.
I'd start the next session by pointing straight at the plan file and the exact behavior I want (like I did with the CancellationException bug report), since giving the agent the precise symptom and fix upfront meant it found the bug fast and fixed it correctly first try. The real friction was at the end: my web search tooling (duckduckgo MCP, perplexity) was broken or unavailable, so I'd first verify search tooling works before asking the agent to research a library, rather than burning turns on curl/python fallbacks that also failed.