# `deslop/feature-flag`

Disallow stale feature flags that permanently guard dead code.

- **Category:** Dead Code
- **Severity:** warn
- **Source:** deslop-js
- **Framework:** global
- **Enabled when:** react-doctor deadCode analysis enabled (default true); whole-project scan only — skipped in --diff/--staged modes
- **Documentation:** <https://github.com/millionco/deslop-js>

## Validation prompt

Use this to decide whether a fired diagnostic is real or a false positive.

Fires when deslop's feature-flag detector records a FeatureFlag (kind env-var, sdk-call, or config-object) whose guardsDeadCode is true — meaning the flag's enclosing if/ternary guard span (guardLineStart..guardLineEnd) overlaps a line that is itself reported as an unusedExport: an env-var like process.env.FEATURE_X / FF_X / NEXT_PUBLIC_ENABLE_X, an SDK call such as boolVariation/useGate/checkGate/isEnabled/getTreatment/useFeatureFlagEnabled/flag (sdkProvider names the vendor: LaunchDarkly, Statsig, Unleash, GrowthBook, Split, PostHog, Vercel Flags), or a config-object access like config.features / settings.toggle. False positive to suppress: a flag still actively toggled for a live rollout, A/B experiment, or kill-switch where BOTH branches are reachable and serve real traffic — only permanently-settled flags (the detector's guardsDeadCode==true / unreachable guarded branch) are cleanup candidates, so suppress if the flag's value still varies in production or the disabled branch is intentionally kept warm.

## Fix prompt

Use this once validation confirms the diagnostic is real.

Retire the settled flag and inline the surviving branch: confirm the flag is permanently on (or off) in every environment, then delete the if/ternary guard, the unused branch, the flag lookup (the process.env read, the SDK call like boolVariation('x') / useGate('x'), or the config.features.x access), plus the now-orphaned env entry, SDK registration, or config key — e.g. replace `if (boolVariation('newCheckout')) renderNew(); else renderOld();` with just `renderNew();` and drop renderOld. A flag guarding code the rest of the repo no longer imports is finished rolling out; leaving it forces every reader to reason about a dead branch. See https://github.com/millionco/deslop-js