---
phase: 19-checkout-command
verified: 2026-01-20T02:30:00Z
status: passed
score: 10/10 must-haves verified
---

# Phase 19: Checkout Command Verification Report

**Phase Goal:** Users can use the overloaded git checkout command with correct disambiguation between switching branches, restoring files, and creating branches
**Verified:** 2026-01-20T02:30:00Z
**Status:** passed
**Re-verification:** No - initial verification

## Goal Achievement

### Observable Truths

| # | Truth | Status | Evidence |
|---|-------|--------|----------|
| 1 | User can switch to an existing branch with git checkout <branch> | VERIFIED | handle() routes to `run_sl(["goto"] + args)` when target is valid revision (line 147) |
| 2 | User can switch to a commit with git checkout <commit> | VERIFIED | `_is_valid_revision()` validates via `sl log -r`, then `run_sl(["goto"])` (lines 11-27, 147) |
| 3 | User can restore a file with git checkout <file> or git checkout -- <file> | VERIFIED | Routes to `run_sl(["revert"] + args)` for file targets (line 151), `run_sl(["revert"] + after_sep)` with separator (line 126) |
| 4 | User can create and switch to a new branch with git checkout -b <name> | VERIFIED | `_handle_create_branch()` creates bookmark and switches (lines 46-84) |
| 5 | Ambiguous arguments error clearly instead of wrong action | VERIFIED | Lines 138-143 check both revision and file, print "could be both" error |
| 6 | Tests verify checkout <commit> works | VERIFIED | TestCheckoutCommit class with 2 tests (lines 19-43) |
| 7 | Tests verify checkout <branch> works | VERIFIED | TestCheckoutBranch class with 2 tests (lines 46-68) |
| 8 | Tests verify checkout <file> and checkout -- <file> work | VERIFIED | TestCheckoutFile class with 3 tests (lines 71-114) |
| 9 | Tests verify checkout -b <name> creates branch | VERIFIED | TestCheckoutCreateBranch class with 3 tests (lines 117-160) |
| 10 | Tests verify ambiguity detection and error message | VERIFIED | TestCheckoutDisambiguation class with 4 tests (lines 163-227) |

**Score:** 10/10 truths verified

### Required Artifacts

| Artifact | Expected | Status | Details |
|----------|----------|--------|---------|
| `cmd_checkout.py` | Checkout handler with disambiguation | VERIFIED | 155 lines, exports `handle()`, has `_is_valid_revision()`, `_split_at_separator()`, `_handle_create_branch()` |
| `tests/test_checkout.py` | E2E tests for all checkout requirements | VERIFIED | 245 lines, 6 test classes, 16 tests total |
| `gitsl.py` | Dispatch routing for checkout | VERIFIED | Line 33: `import cmd_checkout`, Line 131: `return cmd_checkout.handle(parsed)` |
| `pytest.ini` | checkout marker registered | VERIFIED | Line 8: `checkout: tests for git checkout command` |

### Key Link Verification

| From | To | Via | Status | Details |
|------|-----|-----|--------|---------|
| gitsl.py | cmd_checkout.py | import and dispatch | WIRED | `import cmd_checkout` (line 33), `cmd_checkout.handle(parsed)` (line 131) |
| cmd_checkout.py | common.py | ParsedCommand, run_sl | WIRED | `from common import ParsedCommand, run_sl` (line 8), run_sl used 8 times |
| tests/test_checkout.py | conftest.py | fixtures | WIRED | Uses `sl_repo_with_commit` fixture (20+ usages), `sl_repo_with_commits` fixture |

### Requirements Coverage

| Requirement | Status | Implementation |
|-------------|--------|----------------|
| CHECKOUT-01: checkout <commit> -> goto | VERIFIED | Lines 145-147: `if is_revision: return run_sl(["goto"] + args)` |
| CHECKOUT-02: checkout <branch> -> goto | VERIFIED | Same as CHECKOUT-01 (bookmarks are valid revisions) |
| CHECKOUT-03: checkout <file> -> revert | VERIFIED | Lines 149-151: `if is_file: return run_sl(["revert"] + args)` |
| CHECKOUT-04: checkout -- <file> -> revert | VERIFIED | Lines 120-126: handles `--` separator |
| CHECKOUT-05: checkout -b -> bookmark + goto | VERIFIED | Lines 112-114: delegates to `_handle_create_branch()` |
| CHECKOUT-06: disambiguation logic | VERIFIED | Lines 137-143: checks both revision and file, errors on ambiguity |

### Anti-Patterns Found

| File | Line | Pattern | Severity | Impact |
|------|------|---------|----------|--------|
| - | - | None found | - | - |

No TODO, FIXME, placeholder, or stub patterns found in either `cmd_checkout.py` or `tests/test_checkout.py`.

### Human Verification Required

| # | Test | Expected | Why Human |
|---|------|----------|-----------|
| 1 | Run `python3 gitsl.py checkout <branch>` in real sl repo | Switches to branch successfully | Pytest unavailable in verification environment; needs actual sl execution |
| 2 | Run `python3 gitsl.py checkout -b new-branch` in real sl repo | Creates and switches to new bookmark | Verifies bookmark + goto sequence |
| 3 | Run `python3 gitsl.py checkout -- <file>` after modifying file | Restores file content | Verifies revert execution |
| 4 | Create file with same name as bookmark, run checkout without -- | Should error with "could be both" message | Verifies disambiguation behavior |

### Code Quality Assessment

**cmd_checkout.py (155 lines):**
- Clean separation: 4 functions with single responsibilities
- Proper typing: `List`, `Optional`, `Tuple` type hints
- Complete docstrings for all functions
- All 6 CHECKOUT requirements documented in `handle()` docstring
- No stub patterns, no placeholders

**tests/test_checkout.py (245 lines):**
- 6 well-organized test classes by requirement
- 16 comprehensive tests covering all cases
- Uses appropriate fixtures (`sl_repo_with_commit`, `sl_repo_with_commits`)
- No placeholder tests

## Verification Summary

Phase 19 goal is **achieved**. All must-haves from the PLAN frontmatter are verified:

1. **cmd_checkout.py** - Complete implementation (155 lines)
   - `handle()` main function with full disambiguation logic
   - `_is_valid_revision()` for revision detection via `sl log -r`
   - `_split_at_separator()` for `--` handling
   - `_handle_create_branch()` for `-b/-B` branch creation

2. **gitsl.py dispatch** - Correctly imports and routes to cmd_checkout

3. **tests/test_checkout.py** - Comprehensive E2E tests (245 lines, 16 tests)
   - All 6 CHECKOUT requirements have test coverage
   - Uses proper fixtures from conftest.py

4. **Requirements** - All 6 CHECKOUT requirements implemented:
   - CHECKOUT-01 through CHECKOUT-06 covered in code and tests

---

*Verified: 2026-01-20T02:30:00Z*
*Verifier: Claude (gsd-verifier)*
