---
phase: 01-dedup-floor-fix
plan: 01
subsystem: core-algorithm
tags: [rust, processor, checkpoint, dedup, stathera, trade-id]

# Dependency graph
requires: []
provides:
  - "last_completed_bar_tid field and accessor on OpenDeviationBarProcessor"
  - "last_completed_bar_tid persistence in Checkpoint with backward compat"
  - "Field updates only on bar completion and orphan emission, not every trade"
affects: [01-02, live_engine, committed_floors]

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "serde(default) for backward-compatible checkpoint field additions"
    - "Separate tracking of completed-bar state vs forming-bar tail"

key-files:
  created: []
  modified:
    - "crates/opendeviationbar-core/src/processor.rs"
    - "crates/opendeviationbar-core/src/checkpoint.rs"
    - "crates/opendeviationbar-core/tests/processor_tests.rs"

key-decisions:
  - "last_completed_bar_tid NOT reset to None in reset_at_ouroboros -- persists across day boundaries for dedup floor continuity"
  - "Orphan bars treated as completed bars for dedup purposes -- orphan emission updates last_completed_bar_tid"

patterns-established:
  - "v1.4 field addition pattern: processor field + checkpoint field with serde(default) + accessor + TDD"

requirements-completed: [RUST-01]

# Metrics
duration: 3min
completed: 2026-03-21
---

# Phase 01 Plan 01: last_completed_bar_tid Tracking Summary

**Added last_completed_bar_tid field to OpenDeviationBarProcessor and Checkpoint, tracking completed bar trade IDs separately from forming bar tail for dedup floor initialization**

## Performance

- **Duration:** 3 min
- **Started:** 2026-03-21T05:58:29Z
- **Completed:** 2026-03-21T06:01:44Z
- **Tasks:** 1
- **Files modified:** 3

## Accomplishments

- Added `last_completed_bar_tid: Option<i64>` field to `OpenDeviationBarProcessor` struct with public accessor
- Field updates ONLY on bar completion (process_single_trade and batch path) and orphan emission (reset_at_ouroboros), never on every trade
- Added field to `Checkpoint` struct with `#[serde(default)]` for backward compatibility with old checkpoints
- Checkpoint round-trip preserves the field via create_checkpoint/from_checkpoint
- 7 TDD tests covering all behaviors: fresh processor, bar completion, no-completion, orphan emission, ouroboros persistence, checkpoint round-trip, backward compat
- All 663 opendeviationbar-core tests pass with zero regressions

## Task Commits

Each task was committed atomically:

1. **Task 1 (RED): Failing tests for last_completed_bar_tid** - `417b6e8` (test)
2. **Task 1 (GREEN): Implementation in processor.rs and checkpoint.rs** - `35905d8` (feat)

_TDD task: RED commit (failing tests) followed by GREEN commit (implementation)_

## Files Created/Modified

- `crates/opendeviationbar-core/src/processor.rs` - Added field, accessor, updates in process_single_trade, batch path, reset_at_ouroboros, checkpoint methods
- `crates/opendeviationbar-core/src/checkpoint.rs` - Added field with serde(default), initialized in Checkpoint::new()
- `crates/opendeviationbar-core/tests/processor_tests.rs` - 7 new tests verifying all behaviors

## Decisions Made

- `last_completed_bar_tid` is NOT reset to None in `reset_at_ouroboros()` -- the field persists across day boundaries because the dedup floor needs to survive ouroboros resets
- Orphan bars are treated as completed bars for dedup purposes -- when an orphan is emitted via `reset_at_ouroboros()`, the field is updated to the orphan's last_agg_trade_id

## Deviations from Plan

None - plan executed exactly as written.

## Issues Encountered

None

## User Setup Required

None - no external service configuration required.

## Next Phase Readiness

- `last_completed_bar_tid()` accessor is ready for Plan 02 to wire into `live_engine.rs` committed_floors initialization
- Checkpoint serialization supports the field, enabling cross-restart persistence

## Self-Check: PASSED

- All 3 modified files exist on disk
- Commit 417b6e8 (RED) verified in git log
- Commit 35905d8 (GREEN) verified in git log
- 663/663 opendeviationbar-core tests pass

---

_Phase: 01-dedup-floor-fix_
_Completed: 2026-03-21_
