လေ့ကျင့်ခန်း — AI Coding Agent များနှင့် Git ကို ဘေးကင်းစွာ အသုံးပြုခြင်း

# One-time setup (once per machine)
git config --global init.defaultBranch main

mkdir project && cd project
git init

# calc.py -- the module the agent will be asked to extend
cat > calc.py <<'EOF'
def add(a, b):
    return a + b
EOF

# test_calc.py -- a passing test for the current code
cat > test_calc.py <<'EOF'
from calc import add


def test_add():
    assert add(2, 3) == 5
EOF

# config.py -- a normal, non-secret config module
cat > config.py <<'EOF'
import os

DATABASE_URL = os.environ.get("DATABASE_URL", "postgres://localhost/myapp_dev")
DEBUG = True
EOF

export GIT_AUTHOR_NAME="Thuta Learner"
export GIT_AUTHOR_EMAIL="learner@example.com"
export GIT_COMMITTER_NAME="Thuta Learner"
export GIT_COMMITTER_EMAIL="learner@example.com"
export GIT_AUTHOR_DATE="2026-02-01T09:00:00"
export GIT_COMMITTER_DATE="2026-02-01T09:00:00"

git add calc.py test_calc.py config.py
git commit -m "Checkpoint: add() function, tests, and config pass before starting agent task"

# ======================================================================
# ROUND 1 -- a BAD agent edit: a real helper PLUS a hardcoded secret
# ======================================================================
# What the agent's round-1 edit actually did to the two files:
printf '\ndef multiply(a, b):\n    return a * b\n' >> calc.py
printf '\nSTRIPE_API_KEY = "sk_live_51H8x2example_do_not_commit"\n' >> config.py

git status
git diff

# Review catches the hardcoded key in config.py -- reject the whole change
git restore calc.py config.py
git status   # back to a clean checkpoint, nothing lost

# ======================================================================
# ROUND 2 -- a GOOD agent edit: a well-scoped function + test
# ======================================================================
# What the agent's round-2 edit actually did to the two files:
printf '\ndef subtract(a, b):\n    return a - b\n' >> calc.py
printf '\ndef test_subtract():\n    assert subtract(5, 3) == 2\n' >> test_calc.py
sed -i 's/from calc import add$/from calc import add, subtract/' test_calc.py

git diff

# Run the test suite before trusting the change
python -c "import test_calc; test_calc.test_add(); test_calc.test_subtract(); print('2 passed')"

export GIT_AUTHOR_DATE="2026-02-01T09:20:00"
export GIT_COMMITTER_DATE="2026-02-01T09:20:00"
git add calc.py test_calc.py
git commit -m "Add subtract() function with test (reviewed AI agent edit)"
git log --oneline