Promote Feature

promote-feature

Guides the staged promotion of a gated FeatureFlag variant to Dogfood, Preview, or Stable, and schedules the follow-up cleanup.

Overview

Feature flags have two interacting layers:

• Runtime (warp_core/src/features.rs): DOGFOOD_FLAGS, PREVIEW_FLAGS, RELEASE_FLAGS — enabled per-channel at startup.
• Compile-time (app/Cargo.toml + app/src/lib.rs): Cargo features in [features]. The default = [...] array enables a feature for all builds. enabled_features() in app/src/lib.rs bridges each Cargo feature to its FeatureFlag variant via #[cfg(feature = "...")].

Do not remove the flag immediately after promoting to Stable. Keep it for at least 1–2 release cycles so a rollback is a one-line PR (remove the entry from default). Use the remove-feature-flag skill for the cleanup step later.

Promote to Dogfood

Add the flag to DOGFOOD_FLAGS in warp_core/src/features.rs:

pub const DOGFOOD_FLAGS: &[FeatureFlag] = &[
    // ...
    FeatureFlag::YourFeature,
];

No other file changes needed.

Promote to Preview

1. Add to PREVIEW_FLAGS in warp_core/src/features.rs. 2. Remove from DOGFOOD_FLAGS if present — Preview flags are automatically included in Dogfood builds.

pub const PREVIEW_FLAGS: &[FeatureFlag] = &[
    // ...
    FeatureFlag::YourFeature,
];

Promote to Stable

This requires changes in three files.

1. app/Cargo.toml — add to default

Add the snake_case feature name to the default = [...] array:

default = [
    # ...
    "your_feature_name",
]

Prefer this over adding to RELEASE_FLAGS (see comment at warp_core/src/features.rs:787-790). It compiles the feature into all builds and enables a one-line rollback.

2. app/src/lib.rs — add to enabled_features() bridge

Add a #[cfg(...)] entry inside the flags.extend([...]) block in enabled_features(), following the existing pattern:

#[cfg(feature = "your_feature_name")]
FeatureFlag::YourFeature,

Place it near logically related entries.

3. warp_core/src/features.rs — remove from PREVIEW_FLAGS / DOGFOOD_FLAGS

Remove the variant from whichever arrays it currently lives in:

pub const PREVIEW_FLAGS: &[FeatureFlag] = &[
    // Remove FeatureFlag::YourFeature,
];

Validate

./script/format
cargo clippy --workspace --all-targets --all-features --tests -- -D warnings

Create a follow-up Linear issue

After the PR lands, create a Linear issue to remind the team to remove the flag. Use the Linear MCP tool:

save_issue(
  title: "Remove FeatureFlag::YourFeature after stabilization",
  team: <your team>,
  assignee: "me",
  description: "FeatureFlag::YourFeature was promoted to Stable in <PR link>. Remove the flag and dead code branches after 1–2 release cycles. Follow the `remove-feature-flag` skill.",
  labels: ["tech-debt"],
  priority: 4  // Low
)