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Defer broad Annex B support before 1.0

Date: 2026-07-01 Area: language, test262 Issue: #853 Supersedes: ADR 0061 as a general Annex B policy statement; ADR 0061 remains the historical record for the labelled-function implementation boundary.

GocciaScript will not pursue broad ECMA-262 Annex B support for this release or before 1.0. Annex B is a web-browser legacy compatibility annex, not part of the core ECMAScript language, and ECMA-262 discourages non-browser implementations from adding those features unless they must run the same legacy web code as browsers. That does not match the current product direction in VISION.md: sandbox-first execution for agents, embeddable desktop runtimes, and no full browser host environment today.

The Annex B test262 baseline from #853 is retained as a measurement snapshot, not a release target: bytecode mode ran 1086 Annex B tests with 476 pass, 602 fail, 8 wrapper-infra failures, and 0 timeouts; interpreted mode ran the same 1086 tests with 495 pass, 583 fail, 8 wrapper-infra failures, and 0 timeouts. The existing passing surface mostly comes from features that were already implemented for broader ECMAScript compatibility or as targeted shims, such as String.prototype.substr, object legacy accessors, Date.prototype.toGMTString, and sloppy block-function behavior behind existing compatibility flags.

The decision is intentionally narrower than "remove all Annex B-shaped behavior". Existing implemented surfaces may remain when they already support current conformance work, avoid churn, or are exposed as documented shims. New work should not add Annex B parser, binding, object-model, RegExp legacy, or browser-host semantics just to improve the annexB category. A future Web API or browser-compatibility product direction may re-open Annex B as an explicit compatibility profile, because browser-style host compatibility is the point where Annex B becomes strategically coherent.

Consequences:

  • annexB stays excluded from the default test262 category set.
  • Annex B pass rate is informational only and should not be treated as a pre-1.0 release gate.
  • Shim-level legacy names may still be implemented when they layer cleanly over existing modern primitives and are useful outside a browser-host profile.
  • Native Annex B semantics that require parser, binding-instantiation, object-model, RegExp-internal, or host hooks need a separate post-1.0 design decision, preferably tied to a Web API/browser-compatibility profile.