# Regression Review Report

**Branch**: feat/176-tmux-abstraction-layer -> main
**Date**: 2026-05-17
**Focus**: Regression analysis of shared file modifications

## Issues in Your Changes (BLOCKING)

### CRITICAL

(none)

### HIGH

(none)

### MEDIUM

(none)

## Issues in Code You Touched (Should Fix)

(none)

## Pre-existing Issues (Not Blocking)

(none)

## Suggestions (Lower Confidence)

- **CLAUDE.md not updated with new test scripts** - `CLAUDE.md` (Confidence: 65%) -- The `test:tmux` and `test:tmux:integration` scripts are not listed in CLAUDE.md's test commands section or the pre-release validation block. This is documentation drift, not a functional regression, but could lead to the new tests being skipped during manual release validation.

- **Inconsistent `isTmuxAvailable()` between integration test files** - `tests/integration/tmux/sentinel-detection.test.ts:24` vs `session-lifecycle.test.ts:22` (Confidence: 70%) -- `session-lifecycle.test.ts` includes a probe session check (create + destroy a test session) to verify the tmux server is actually functional, while `sentinel-detection.test.ts` only checks for the binary and version >= 3. In CI environments where the binary exists but no server/socket support is available, sentinel tests could fail while lifecycle tests skip properly. Both files document graceful skipping but use different heuristics.

- **`test:all` ordering puts tmux last** - `package.json:20` (Confidence: 60%) -- The two tmux test suites are appended to the end of the `test:all` chain. If tmux tests were to fail (not skip, but actually error), all preceding suites would have already run successfully and the failure would only surface at the very end. This is a minor concern since the skip logic appears correct, but worth noting.

## Summary

| Category | CRITICAL | HIGH | MEDIUM | LOW |
|----------|----------|------|--------|-----|
| Blocking | 0 | 0 | 0 | - |
| Should Fix | - | 0 | 0 | - |
| Pre-existing | - | - | 0 | 0 |

**Regression Score**: 9/10
**Recommendation**: APPROVED

## Detailed Analysis

### 1. ErrorCode enum (src/core/errors.ts) -- No Regression

All 29 existing enum values are preserved verbatim. The 4 new values (`TMUX_SESSION_FAILED`, `TMUX_VALIDATION_FAILED`, `TMUX_HOOK_FAILED`, `TMUX_SEND_KEYS_FAILED`) are appended at the end of the enum, after the last existing value `ORCHESTRATION_NOT_FOUND`. This is a purely additive change.

The 4 new factory functions (`tmuxSessionFailed`, `tmuxValidationFailed`, `tmuxHookFailed`, `tmuxSendKeysFailed`) are also additive -- inserted before the existing `isAutobeatError` and `toAutobeatError` guards, which remain unchanged.

No existing export signatures changed. No existing exports removed. All 46 existing consumers of `errors.ts` across the codebase are unaffected.

### 2. package.json test scripts -- No Regression

| Script | Change | Risk |
|--------|--------|------|
| `test:all` | Appended `&& npm run test:tmux && npm run test:tmux:integration` | None -- additive chaining |
| `test:implementations` | Added `--exclude='**/tmux/**'` | None -- prevents accidental double-run |
| `test:integration` | Added `--exclude='**/tmux/**'` | None -- prevents accidental double-run |
| `test:tmux` (new) | New script for tmux unit tests | None -- new, no conflict |
| `test:tmux:integration` (new) | New script for tmux integration tests | None -- new, no conflict |

The exclusion pattern `--exclude='**/tmux/**'` correctly isolates tmux tests from the existing `test:implementations` and `test:integration` suites, preventing double-running and potential test interference.

### 3. CI Impact -- Safe

Both CI workflows (`ci.yml`, `release.yml`) use `npm run test:all`. The extended chain will now include tmux tests. Integration tests skip gracefully via `isTmuxAvailable()` checks. Unit tests are fully mocked with no tmux dependency.

### 4. Barrel Export (src/implementations/tmux/index.ts) -- Safe

The barrel export uses `export type` for type-only re-exports and named exports for implementations. No side effects at import time. No existing barrel exports are modified -- this is a new file in a new directory.

### 5. Feature Index (.features/index.json) -- Safe

Changed from empty features object to include two tmux feature entries. No existing feature entries removed or modified.
