PERF_VERSION_TAG

PERF_VERSION_TAG is a build-identifier string used in telemetry to disambiguate ablation runs from baseline runs. It is derived from the current BUILD_VERSION plus any active perf flags.

Derivation

Defined in engine/core/config/_perf-flags.ts:

• If no perf flags are active, PERF_VERSION_TAG = BUILD_VERSION (e.g. v5.285.0).
• If one or more perf flags are active, PERF_VERSION_TAG = ${BUILD_VERSION}-${flagsList.join('-')} (e.g. v5.285.0-noStickers-noTerrain).

The active-flags list is built by iterating PERF_FLAGS and including any entry whose value is === true. Non-boolean entries (devScenario, dprOverride) and boolean entries that are false are excluded.

Why it exists

Telemetry events tagged only with BUILD_VERSION cannot distinguish between a normal session and a session running an ablation (e.g. ?noStickers=1&noTerrain=1). Mixing those sample groups would pollute baseline perf metrics. Including the active-flag list in the version tag keeps ablation samples in a separate bucket.

Example values

• v5.285.0 — baseline, no flags.
• v5.285.0-noStickers — sticker rendering disabled.
• v5.285.0-noStickers-noTerrain — stickers and terrain both disabled.
• v5.285.0-isMobile — mobile device (the isMobile flag is itself a PERF_FLAGS entry and propagates into the tag).

See also

• engine/core/config/_perf-flags.ts — definition.
• BUILD_VERSION in engine/core/config/_version.ts.