#+TITLE: Worker CLI Cleanup: Exit Codes, Refactors, and Tech Debt Resolution
#+DATE: 2026-01-11
#+KEYWORDS: worker-cli, nim, refactoring, exit-codes, sqlite, state-machine, testing
#+COMMITS: 10
#+COMPRESSION_STATUS: uncompressed

* Session Summary
** Date: 2026-01-11 (Day 2 of worker CLI implementation)
** Focus Area: Code quality cleanup and tech debt resolution for worker CLI

This session continued from yesterday's multi-agent worker CLI implementation, focusing
on fixing bugs discovered during testing, completing P3/P4 refactoring tasks, and
ensuring all loose ends were tied up.

* Accomplishments
- [X] Fixed exit codes bug (skills-lxb9) - state transition errors now return code 3
- [X] Fixed double ROLLBACK bug in state.nim transaction handling
- [X] Extracted poll() null-check helper with generic optFromDb function
- [X] Extracted rowToWorkerInfo helper to deduplicate getWorker/getAllWorkers
- [X] Extracted loadContextFromPath helper to deduplicate context loading
- [X] Created developer docs for compiling/deployment workflow
- [X] Consolidated isStale/staleLevel into single computeStaleLevel with enum
- [X] Refactored transition functions to use withTransaction template
- [X] Added schema migration infrastructure for future DB changes
- [X] Extracted renderStatusTable from nested proc in status()
- [X] Added column width constants for status table
- [X] Replaced case statement with parseEnum for heartbeat status
- [X] Added return value to startGlobalHeartbeat for caller feedback
- [X] Removed unused getBranchStatus function (dead code)
- [X] Ran comprehensive integration testing throughout

* Key Decisions
** Decision 1: Use StaleLevel enum instead of string returns
- Context: isStale() and staleLevel() had duplicated logic for computing staleness
- Options considered:
  1. Keep separate functions with shared helper
  2. Create enum and single source of truth function
- Rationale: Enum provides type safety, single computeStaleLevel is canonical
- Impact: Cleaner API, easier to add new stale levels in future

** Decision 2: Remove getBranchStatus rather than keep unused code
- Context: Function existed but was never called anywhere
- Options considered:
  1. Keep for potential future use
  2. Remove and restore from git history if needed
- Rationale: Dead code creates maintenance burden; git preserves history
- Impact: Smaller, cleaner codebase

** Decision 3: Leave tryClaim with inline transaction handling
- Context: tryClaim has different semantics (returns bool, doesn't raise)
- Options considered:
  1. Create withTransactionOrFalse variant
  2. Leave as-is with inline handling
- Rationale: Over-engineering for one function; semantics differ from withTransaction
- Impact: Pragmatic choice, tryClaim remains readable

* Problems & Solutions
| Problem | Solution | Learning |
|---------|----------|----------|
| Double ROLLBACK causing "no transaction active" | Removed inline ROLLBACKs, let except block handle | Single rollback point prevents double-free pattern |
| StaleState not caught, wrong exit code | Added except StaleState alongside InvalidTransition | Map all state errors to same exit code |
| Tests failing with NOT_FOUND for DB queries | sqlite3 wasn't in PATH; set LD_LIBRARY_PATH and PATH | Test environment needs explicit sqlite setup |
| parseEnum type not matching HeartbeatStatus | HeartbeatStatus enum values match string literals exactly | Nim parseEnum uses enum value strings |

* Technical Details

** Code Changes
- Total files modified: 13
- Key files changed:
  - =src/worker.nim= - Exit code handling, renderStatusTable extraction, parseEnum
  - =src/worker/state.nim= - withTransaction usage, StaleLevel enum, rowToWorkerInfo
  - =src/worker/db.nim= - Migration infrastructure, optFromDb in poll()
  - =src/worker/utils.nim= - optFromDb generic helper
  - =src/worker/context.nim= - loadContextFromPath extraction
  - =src/worker/heartbeat.nim= - startGlobalHeartbeat return value
  - =src/worker/git.nim= - Removed unused getBranchStatus
  - =src/worker/types.nim= - StaleLevel enum
- New files created:
  - =docs/worker-cli-dev-guide.md= - Developer documentation

** Commands Used
#+begin_src bash
# Compile worker
nix-shell -p nim --run "nim c -d:release --mm:orc src/worker.nim"

# Run tests with sqlite in environment
bash -c 'export LD_LIBRARY_PATH=/nix/store/.../lib; \
         export PATH=$PATH:/nix/store/.../bin; \
         src/worker/tests/test-worker.sh'

# Find sqlite library paths on NixOS
find /nix/store -name "libsqlite3.so" | head -1
find /nix/store -name "sqlite3" -type f | grep bin | head -1
#+end_src

** Architecture Notes
- Transaction handling: Single withTransaction template with ROLLBACK in except block
- State machine: Exceptions flow through, caller handles WorkerNotFound/StaleState/InvalidTransition
- Schema migrations: Version-based, forward-only, runs automatically on DB open
- Column constants: Centralized for consistent table formatting

* Process and Workflow

** What Worked Well
- Incremental refactoring with test verification after each change
- Using beads issues to track and close work systematically
- Integration testing caught the double-ROLLBACK bug early
- TodoWrite for tracking progress through multiple small tasks

** What Was Challenging
- Network down prevented pushing to remote throughout session
- NixOS sqlite library path discovery requires manual lookup
- Context recovery from session compaction required careful reading

* Learning and Insights

** Technical Insights
- Nim's ORC handles ref types cleanly; no manual memory management needed
- tiny_sqlite ResultRow works directly with openArray-like indexing
- parseEnum is cleaner than case statements for string-to-enum conversion
- withTransaction template elegantly handles BEGIN/COMMIT/ROLLBACK pattern

** Process Insights
- P4 tasks compound quickly; worth batching them together
- Code review findings from previous session created useful task backlog
- Comprehensive test suite catches regressions during refactoring

** Architectural Insights
- State machine exceptions should be unified at handler level (all -> exit code 3)
- Schema migrations need to be idempotent and forward-only
- Separating render logic from CLI dispatch improves testability

* Context for Future Work

** Open Questions
- Should query procs move from state.nim to db.nim? (skills-8la4, P4)
- Rollback strategy for failed workers needs design (skills-7n4, P3)
- Git bundle checkpoints evaluation pending (skills-8ak, P3)

** Next Steps
- Push commits when network available
- Design doc for rollback strategy
- Consider multi-agent orchestration integration points

** Related Work
- [[file:2026-01-10-multi-agent-lego-architecture-design.org][Multi-Agent Lego Architecture Design]] - Previous session
- =docs/adr/006-nim-worker-cli.md= - ADR for Nim language choice
- =docs/worker-cli-dev-guide.md= - Developer documentation created this session

* Raw Notes
Session was continuation of worker CLI implementation. Primary focus shifted from
feature development to code quality and bug fixes discovered during testing.

The exit codes bug was interesting - the state machine was raising StaleState when
current state didn't match expected state, but the CLI commands only caught
InvalidTransition. This caused unhandled exception behavior with wrong exit codes.

The double-ROLLBACK bug was subtle: transition() had inline ROLLBACKs before raising
exceptions, then the except block tried to ROLLBACK again. SQLite correctly rejected
the second ROLLBACK since there was no active transaction.

Network was down throughout session (192.168.1.108:3000 unreachable), so all work
is committed locally but not pushed. Will need to push when network recovers.

* Session Metrics
- Commits made: 10
- Files touched: 13
- Lines added/removed: +980/-241
- Tests added: 0 (existing test suite used)
- Tests passing: 56/56
