fix(jsc): AsyncDisposableStack.use() with sync @@dispose fallback

[robobun]

Summary

Fixes #24277

• Add regression test for AsyncDisposableStack.prototype.use() throwing TypeError: @@asyncDispose must be callable when passed an object with only Symbol.dispose (not Symbol.asyncDispose)
• The actual fix is in the WebKit/JSC fork: Fix getAsyncDisposableMethod to fall back to @@dispose per TC39 spec WebKit#162

Root cause

The getAsyncDisposableMethod JSC builtin function had two bugs:

1. It checked !isCallable(method) before isUndefinedOrNull(method), causing a TypeError when @@asyncDispose was undefined instead of falling through to the undefined check
2. It was missing the fallback to @@dispose entirely — per the TC39 spec (GetDisposeMethod with hint async-dispose), if @@asyncDispose is not present, the runtime should fall back to @@dispose and wrap it in a Promise adapter

Additionally, AsyncDisposableStackPrototype.use() was using @getDisposableStackInternalField (sync) instead of @getAsyncDisposableStackInternalField (async).

What this PR adds

A regression test that validates:

• AsyncDisposableStack.use() with sync @@dispose falls back correctly
• await using with sync @@dispose works correctly
• Objects with neither @@asyncDispose nor @@dispose still throw TypeError
• Objects with @@asyncDispose continue to work as before

WebKit dependency

This PR depends on the WebKit fix in oven-sh/WebKit#162 being merged and a new WebKit release being created with the updated commit hash in cmake/tools/SetupWebKit.cmake.

Test plan

• Test fails with system bun (confirms the bug exists)
• Test passes with debug build using patched local WebKit (WEBKIT_LOCAL=ON)
• Original reproduction case from issue works correctly

🤖 Generated with Claude Code

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[robobun]

^{Updated 10:14 AM PT - Feb 19th, 2026}

❌ Your commit 99b36194 has 3 failures in Build #37597 (All Failures):

• test/integration/next-pages/test/dev-server.test.ts - 1 failing on 🍎 14 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 3.23 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 3.23 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 25.04 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 13 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 14 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 13 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 14 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 13 aarch64
• test/regression/issue/024277.test.ts - 1 failing on 🐧 3.23 x64 (new)
• test/regression/issue/024277.test.ts - 1 failing on 🐧 3.23 aarch64 (new)
• test/regression/issue/024277.test.ts - 1 failing on 🐧 25.04 x64-baseline (new)
• test/regression/issue/024277.test.ts - 1 failing on 🐧 13 x64-baseline (new)
• test/regression/issue/024277.test.ts - 1 failing on 🍎 14 x64 (new)
• test/regression/issue/024277.test.ts - 1 failing on 🍎 13 x64 (new)
• test/regression/issue/024277.test.ts - 1 failing on 🍎 14 aarch64 (new)
• test/regression/issue/024277.test.ts - 1 failing on 🍎 13 aarch64 (new)

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🧪   To try this PR locally:

bunx bun-pr 27168

That installs a local version of the PR into your bun-27168 executable, so you can run:

bun-27168 --bun

[claude]

✅ 99b36 — Looks good!

Reviewed 1 file in test/regression/issue/: Adds a regression test verifying that AsyncDisposableStack.prototype.use() correctly falls back to synchronous Symbol.dispose when Symbol.asyncDispose is not present, per the TC39 Explicit Resource Management specification.