payfrit/payfrit-beacon-ios
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

fix: resolve FFE2 characteristic lost during write #18

Closed
schwifty wants to merge 0 commits from schwifty/fix-ffe2-characteristic-lost into main
pull from: schwifty/fix-ffe2-characteristic-lost
merge into: payfrit:main
Conversation 0 Commits - Files changed -
schwifty commented 2026-03-22 04:48:20 +00:00
Collaborator
Copy link

Summary

  • Root cause: CoreBluetooth invalidates cached CBCharacteristic references during BLE connection parameter renegotiation (common at edge-of-range), causing our characteristics[] dictionary to return nil mid-write
  • Fix: Added resolveCharacteristic() method that falls back to walking the peripheral's live service list when the cache misses, plus didModifyServices delegate to proactively clear stale cache entries and re-discover
  • Replaces all direct characteristics[] lookups with resolveCharacteristic() — also eliminates a force-unwrap on FFE1 subscribe

Test plan

  • Happy path: Provision a beacon at normal range — full command queue completes without issues
  • Edge-of-range: Provision at weak signal to trigger connection parameter renegotiation mid-write — should no longer crash with "FFE2 characteristic lost"
  • Service invalidation recovery: Confirm live service resolution fallback grabs a valid characteristic when the dictionary entry is stale
  • Read config flow: Verify beacon check still reads UUID/major/minor/name correctly

🤖 Generated with Claude Code

## Summary - **Root cause**: CoreBluetooth invalidates cached `CBCharacteristic` references during BLE connection parameter renegotiation (common at edge-of-range), causing our `characteristics[]` dictionary to return nil mid-write - **Fix**: Added `resolveCharacteristic()` method that falls back to walking the peripheral's live service list when the cache misses, plus `didModifyServices` delegate to proactively clear stale cache entries and re-discover - Replaces all direct `characteristics[]` lookups with `resolveCharacteristic()` — also eliminates a force-unwrap on FFE1 subscribe ## Test plan - [ ] Happy path: Provision a beacon at normal range — full command queue completes without issues - [ ] Edge-of-range: Provision at weak signal to trigger connection parameter renegotiation mid-write — should no longer crash with "FFE2 characteristic lost" - [ ] Service invalidation recovery: Confirm live service resolution fallback grabs a valid characteristic when the dictionary entry is stale - [ ] Read config flow: Verify beacon check still reads UUID/major/minor/name correctly 🤖 Generated with [Claude Code](https://claude.com/claude-code)
schwifty added 1 commit 2026-03-22 04:48:21 +00:00 
When CoreBluetooth renegotiates connection parameters (common at edge-of-range),
it can invalidate cached CBCharacteristic references, causing the characteristics
dictionary to return nil mid-write. This resulted in "FFE2 characteristic lost
during write" failures.

Changes:
- Add resolveCharacteristic() with live service fallback when cache misses
- Implement peripheral(_:didModifyServices:) to handle service invalidation
- Replace all direct characteristics[] lookups with resolveCharacteristic()
- Eliminates force-unwrap on FFE1 notification subscribe

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
schwifty closed this pull request 2026-03-22 18:43:36 +00:00

Pull request closed

This pull request cannot be reopened because the branch was deleted.
Sign in to join this conversation.
Reviewers
No reviewers
Labels
Clear labels
No items
No labels
Milestone
Clear milestone
No items
No milestone
Projects
Clear projects
No items
No project
Assignees
Clear assignees
No assignees
1 participant
Notifications
Due date
The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference: payfrit/payfrit-beacon-ios#18
No description provided.
Delete branch "schwifty/fix-ffe2-characteristic-lost"

Deleting a branch is permanent. Although the deleted branch may continue to exist for a short time before it actually gets removed, it CANNOT be undone in most cases. Continue?