Narrow TLA-reentry skip to actual re-entry, not sibling static imports

[robobun]

Problem

innerModuleEvaluation's Bun-specific skip for the spec-mandated async-dependency wait (11.c.v) was too broad: when a TLA leaf module (no async deps of its own, pendingAsyncDependencies always 0) is imported by a sibling in the same Evaluate() pass, the sibling skipped the wait and executed before the TLA body had progressed past its first await. Any binding declared after that await was still in TDZ, giving Cannot access X before initialization on the sibling's use.

Reproduction (oven-sh/bun#30259):

// root.ts
import { foo } from "./await.ts";
import "./child.ts";
void foo;

// await.ts
await 0;
export const foo = 123;

// child.ts
import { foo } from "./await.ts";
console.log(foo);

Fix

The skip was designed for the Nitro-style require(esm) re-entry where a TLA module's body is synchronously re-entered from within its own continuation. Additionally require that no entry in the cycle root's asyncParentModules is on the current DFS stack. When an ancestor is on stack, we're in the same Evaluate() pass that popped this SCC to EvaluatingAsync and the spec wait is mandatory.

This keeps the existing behaviour for the dynamic-import re-entry case (Nitro) while restoring spec-compliant waiting for sibling static imports.

Companion PR

oven-sh/bun# — bumps WEBKIT_VERSION once this is merged and autobuild publishes.

Fixes oven-sh/bun#30259.

[coderabbitai]

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Reviewing files that changed from the base of the PR and between d5ed1db and 5882d99.

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• Source/JavaScriptCore/runtime/AbstractModuleRecord.cpp

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Walkthrough

Updated the top-level await dependency resolution logic in innerModuleEvaluation to check whether any async parent module is already on the current DFS stack. This prevents incorrect skipping of the spec-defined PendingAsyncDependencies increment, fixing a regression where subsequent imports of modules with top-level await would fail with ReferenceError.

Changes

TLA Dependency Skip Condition

Layer / File(s)

Summary

Core Logic Fix Source/JavaScriptCore/runtime/AbstractModuleRecord.cpp

The "skip wait" condition in innerModuleEvaluation now additionally checks whether any record in cyclic->asyncParentModules() is present on the current DFS stack. If an async parent is on-stack, the skip is not performed, ensuring module.[[PendingAsyncDependencies]] is properly incremented and the async parent linkage is appended, fixing incorrect ReferenceError on repeated imports of modules with top-level await.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: narrowing a TLA-reentry skip condition to exclude sibling static imports, matching the core modification in the code.
Description check	✅ Passed	The description provides clear problem statement, fix explanation, and reproduction case, though it lacks explicit Bugzilla reference and WebKit PR template formatting.
Linked Issues check	✅ Passed	The code changes directly address issue #30259 by modifying the TLA-reentry skip logic to check asyncParentModules on the DFS stack, preventing premature execution before await bindings are initialized.
Out of Scope Changes check	✅ Passed	All changes are focused on fixing the TLA-reentry skip logic in innerModuleEvaluation, directly addressing the linked issue without unrelated modifications.

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[robobun]

Closing as duplicate of #215 — same diagnosis of the root cause. sosukesuzuki's watermark-based fix is cleaner (uses the existing moduleAsyncEvaluationCount counter instead of walking asyncParentModules against the stack) and already has a Bun-side PR at oven-sh/bun#30262 with the WebKit version bumped to the preview autobuild. Happy to help review if useful.