From f1c3482e7201b6999ffc472f8e9dbeb06fb945da Mon Sep 17 00:00:00 2001
From: Claude Bot <claude-bot@bun.sh>
Date: Thu, 19 Feb 2026 10:12:10 +0000
Subject: [PATCH] Fix getAsyncDisposableMethod to fall back to @@dispose per
 TC39 spec

The getAsyncDisposableMethod builtin was checking !isCallable(method)
before checking isUndefinedOrNull(method), causing a TypeError when
@@asyncDispose was undefined instead of falling back to @@dispose.

Per the TC39 spec (GetDisposeMethod with hint async-dispose):
1. Check for @@asyncDispose first
2. If undefined/null, fall back to @@dispose and wrap in Promise adapter
3. Only throw if neither is available

Also fixes AsyncDisposableStackPrototype.use() which was incorrectly
using @getDisposableStackInternalField instead of
@getAsyncDisposableStackInternalField.

Fixes oven-sh/bun#24277

Co-Authored-By: Claude <noreply@anthropic.com>
---
 .../builtins/AsyncDisposableStackPrototype.js |  2 +-
 .../builtins/DisposableStackPrototype.js      | 27 ++++++++++++++++---
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Source/JavaScriptCore/builtins/AsyncDisposableStackPrototype.js b/Source/JavaScriptCore/builtins/AsyncDisposableStackPrototype.js
index 80619cb01903..15658203de23 100644
--- a/Source/JavaScriptCore/builtins/AsyncDisposableStackPrototype.js
+++ b/Source/JavaScriptCore/builtins/AsyncDisposableStackPrototype.js
@@ -153,7 +153,7 @@ function use(value)
     if (@getAsyncDisposableStackInternalField(this, @asyncDisposableStackFieldState) === @AsyncDisposableStackStateDisposed)
         throw new @ReferenceError("AsyncDisposableStack.prototype.use requires that |this| be a pending AsyncDisposableStack object");
 
-    @addDisposableResource(@getDisposableStackInternalField(this, @disposableStackFieldCapability), value, /* isAsync */ true);
+    @addDisposableResource(@getAsyncDisposableStackInternalField(this, @asyncDisposableStackFieldCapability), value, /* isAsync */ true);
 
     return value;
 }
diff --git a/Source/JavaScriptCore/builtins/DisposableStackPrototype.js b/Source/JavaScriptCore/builtins/DisposableStackPrototype.js
index da3e11a39ff0..21ab82c4de62 100644
--- a/Source/JavaScriptCore/builtins/DisposableStackPrototype.js
+++ b/Source/JavaScriptCore/builtins/DisposableStackPrototype.js
@@ -31,12 +31,31 @@ function getAsyncDisposableMethod(value)
 
     var method = value.@@asyncDispose;
 
+    if (@isUndefinedOrNull(method)) {
+        // Per spec, fall back to @@dispose when @@asyncDispose is not present.
+        method = value.@@dispose;
+
+        if (@isUndefinedOrNull(method))
+            return @undefined;
+
+        if (!@isCallable(method))
+            @throwTypeError("@@dispose must be callable");
+
+        // Wrap the sync dispose method to return a Promise.
+        var syncMethod = method;
+        return () => {
+            try {
+                syncMethod.@call(value);
+            } catch (e) {
+                return @promiseReject(@Promise, e);
+            }
+            return @promiseResolve(@Promise, @undefined);
+        };
+    }
+
     if (!@isCallable(method))
         @throwTypeError("@@asyncDispose must be callable");
 
-    if (@isUndefinedOrNull(method))
-        return @undefined;
-
     return () => {
         try {
             method.@call(value);
@@ -63,7 +82,7 @@ function createDisposableResource(value, isAsync /* , method */)
             if (isAsync) {
                 method = @getAsyncDisposableMethod(value);
                 if (method === @undefined)
-                    @throwTypeError("@@asyncDispose must not be an undefined");
+                    @throwTypeError("Either @@asyncDispose or @@dispose is required");
             } else {
                 method = value.@@dispose;
                 if (!@isCallable(method))