v8 escape hatch: roadmap + tracker

[cs01]

Umbrella tracker for libnode pragma escape hatch work. Landed in #605 + #609.

Shipped

• Node.js runtime escape hatch via // @chadscript: interpret pragma #605 — libnode embed + pragma wrapper + 5 fixtures (require, setTimeout, fs, async, fetch)
• Cross-boundary marshal: native TS imports pragma-file functions #609 — cross-boundary marshal (sync + async primitives)

Tier 1 — quick wins (2-3 days)

• v8 boundary: array marshal for T[] return types #615 — array marshal for T[] returns
• v8 boundary: top-level await in pragma files #616 — top-level await in pragma
• v8 boundary: unhandled promise rejection hook #617 — unhandled promise rejection hook

Tier 2 — structured data (~1 week)

• v8 boundary: method calls on returned objects #618 — method calls on returned objects
• v8 boundary: object field walking for declared returns #619 — object field walking
• v8 boundary: class exports + new across boundary #620 — class exports + new across boundary (depends on v8 boundary: method calls on returned objects #618 + v8 boundary: object field walking for declared returns #619)
• v8 boundary: marshal arity >8 support #621 — marshal arity >8

Tier 3 — load-bearing (~2-3 weeks)

• v8 boundary: callbacks native→JS #622 — callbacks native→JS (EventEmitter/express)
• v8 boundary: ESM import in pragma files #623 — ESM import in pragma

Polish (no hurry)

• v8 boundary: libnode.dylib distribution in release tarballs #624 — libnode distribution in release tarballs (blocker for curl-install users)
• v8 boundary: EmbedderPreload replaces require-rebind prologue #625 — EmbedderPreload replaces require-rebind hack
• v8 boundary: source maps for errors in pragma files #626 — source maps for pragma errors
• v8 boundary: Boehm finalizer for JSHandle lifecycle #627 — Boehm finalizer for JSHandle lifecycle

Orthogonal

• closures capture outer-scope let by value; mutations invisible after closure runs #588 — closure mutation (AOT-side, huge language gap, ~1 week)
• codegen: indirect calls / first-class functions (arr[i](args), getCb()(args)) — LLVM supports natively, chad doesn't lower to it #598 — indirect calls / first-class functions (AOT-side, ~3 days)
• codegen: function-pointer arrays not supported (Array<(x: string) => void>) #586 — function-pointer arrays (pairs with codegen: indirect calls / first-class functions (arr[i](args), getCb()(args)) — LLVM supports natively, chad doesn't lower to it #598)
• type system: formalize 'string | null' (nullable string) with proper narrowing — unblocks clean FFI #599 — string | null nullable narrowing

Design docs

• memory/libnode-swap-plan.md
• memory/v8-escape-hatch-plan.md (superseded by actual impl)
• memory/v8-phase0-status.md (historical)