Design: Add a shipwright ping command that prints pong to stdout and exits 0

Context

Decision

Component Diagram

┌─────────────────────────────────────────────────────────────────┐
│ User │
│ shipwright ping [args] │
└──────────────────┬──────────────────────────────────────────────┘
 │ exec
 ▼
┌─────────────────────────────────────────────────────────────────┐
│ CLI Router (scripts/sw) │
│ case "$cmd" in │
│ hello) exec sw-hello.sh ← existing │
│ ping) exec sw-ping.sh ← NEW │
│ *) error + exit 1 │
│ esac │
└──────────────────┬──────────────────────────────────────────────┘
 │ exec (replaces router process)
 ▼
┌─────────────────────────────────────────────────────────────────┐
│ sw-ping.sh │
│ ┌─────────────┐ ┌──────────────┐ ┌──────────────────────┐ │
│ │ show_help()│ │ main() │ │ lib/helpers.sh │ │
│ │ heredoc │ │ case 1ドル in │ │ (sourced if present)│ │
│ │ USAGE block│ │ "" → pong │ │ info/success/warn/ │ │
│ └─────────────┘ │ -h → help │ │ error fallbacks │ │
│ │ -v → ver │ └──────────────────────┘ │
│ │ * → err │ │
│ └──────────────┘ │
└─────────────────────────────────────────────────────────────────┘
 ▲さんかく direct invocation (test isolation)
 │
┌─────────────────────────────────────────────────────────────────┐
│ sw-ping-test.sh │
│ 6 tests: output, exit 0, --help, -h, --version, invalid exit 1│
│ No mocks needed — script is pure stdout/exit code │
└─────────────────────────────────────────────────────────────────┘
 ▲さんかく
┌─────────────────────────────────────────────────────────────────┐
│ package.json "test" script │
│ ...&& bash scripts/sw-hello-test.sh && │
│ bash scripts/sw-ping-test.sh && ← NEW │
│ bash scripts/sw-hygiene-test.sh && ... │
└─────────────────────────────────────────────────────────────────┘

Interface Contracts

# sw-ping.sh — public interface
#
# Inputs: 1ドル (optional) — one of: "", "--help", "-h", "--version", "-v", <unknown>
# Outputs: stdout — one of: "pong\n", help text, VERSION string, error message
# Exit: 0 on success (no args, --help, --version)
# 1 on unknown arg
#
# Error contract:
# - ERR trap fires on any unexpected non-zero status, prints BASH_SOURCE:LINENO to stderr
# - Unknown arg: error() writes to stderr, show_help() to stdout, exits 1
# - No network calls, no file writes — pure stdout/exit behavior
main() # entry point, called with "$@"
show_help() # prints USAGE block to stdout, no args, no return value
# scripts/sw router contract (ping case):
# Input: cmd="ping", remaining "$@" forwarded
# Effect: exec replaces router process with sw-ping.sh — no return
# Error: if sw-ping.sh missing, exec fails → bash error to stderr
# sw-ping-test.sh:
# assert_equals expected actual description → increments PASS or FAIL, prints result
# assert_exit_code expected actual description → same
# Exit: 0 if FAIL==0, 1 otherwise

Data Flow

shipwright ping
 │
 ▼ scripts/sw parses 1ドル as cmd="ping"
 │ exec scripts/sw-ping.sh (remaining args forwarded)
 │
 ▼ sw-ping.sh main() evaluates ${1:-}
 case "":
 echo "pong" → stdout
 exit 0
 case "--help"|"-h":
 show_help() → stdout (heredoc)
 exit 0
 case "--version"|"-v":
 echo "$VERSION" → stdout
 exit 0
 case *:
 error "Unknown option: 1ドル" → stderr
 show_help() → stdout
 exit 1

Error Boundaries

Alternatives Considered

Implementation Plan

Validation Criteria