trunk (main):
  A ── B ── C ── D ── E ── F ── G ── H ──▶
  ↑    ↑    ↑    ↑    ↑    ↑    ↑    ↑
  │    │    │    │    │    │    │    │
Alice Bob  Bob Alice Bob Alice Alice Bob
(all committing small increments to trunk)

Short-lived branches (optional, < 1 day):
         ├── X ── Y ──┤  (Alice's tiny branch, merged same day)

Feature flags hide incomplete work:
  Feature "new-checkout" exists in code on trunk
  but is disabled in production via a config flag.
  Only enabled when fully tested and ready.

# Feature flag stored in environment config or a feature flag service
# (LaunchDarkly, Unleash, Flagsmith, etc.)

# In your code:
# if (featureFlags.isEnabled('new-checkout-flow')) {
#   return <NewCheckout />;
# }
# return <LegacyCheckout />;

# Developer commits the new-checkout code to trunk
# with the flag OFF (disabled for all users).
git add src/checkout/
git commit -m "feat: add new checkout flow [flag: new-checkout-flow=off]"
git push origin main

# CI/CD deploys to production — users see legacy checkout
# QA team enables the flag for the staging environment to test
# When ready: enable the flag for 1% of users → 10% → 100%

# features.ts — a simple flag store
export const flags = {
  newCheckoutFlow: process.env.FEATURE_NEW_CHECKOUT === 'true',
  darkMode:        process.env.FEATURE_DARK_MODE === 'true',
  betaSearch:      process.env.FEATURE_BETA_SEARCH === 'true',
}

# In component:
# import { flags } from './features'
# const Checkout = flags.newCheckoutFlow ? NewCheckout : LegacyCheckout

# Environment variable in CI/CD pipeline (off by default):
# FEATURE_NEW_CHECKOUT=false  ← production
# FEATURE_NEW_CHECKOUT=true   ← staging / QA

# Start of day: get latest trunk
git pull origin main

# Make a small, focused change
vim src/api/user.ts
# (write code, keep the change minimal — under 200 lines ideally)

# Run tests locally BEFORE committing
npm test
npm run lint

# Stage and commit
git add src/api/user.ts tests/user.test.ts
git commit -m "feat: add email verification to user registration"

# Pull again (someone may have pushed while you were coding)
git pull --rebase origin main

# Push immediately
git push origin main

# Create a branch (must be merged SAME DAY)
git switch -c feat/email-verification
# (< 1 day of work — keep it tiny)

git commit -m "feat: add email verification to user registration"
git push -u origin feat/email-verification

# Open PR for quick review
gh pr create --title "Add email verification" --body "..."
# (get approval within hours, not days)

# Merge
gh pr merge --squash --delete-branch
git switch main
git pull origin main

Every commit to main triggers:
  1. Dependency installation (< 30 seconds)
  2. Unit tests (< 5 minutes)
  3. Integration tests (< 10 minutes)
  4. Static analysis / linting (< 2 minutes)
  5. Build (< 5 minutes)
  6. Deployment to staging (< 5 minutes)
  7. Smoke tests on staging (< 2 minutes)

Total: ideally under 15 minutes.
If CI takes > 30 minutes, TBD becomes painful.