Harden ObjectWrapper iterator helpers against foreign and revoked receivers#2681
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…eivers
The static Iterator and GetLength helpers installed on wrapped CLR objects
(Symbol.iterator and the length accessor getter) hard-cast thisObject to
ObjectWrapper. Two crash modes were reachable from script:
1. Foreign receiver: extracting the function and re-targeting it
(var f = clrList[Symbol.iterator]; f.call({}) or
Object.getOwnPropertyDescriptor(clrList, 'length').get.call({}))
threw an uncaught InvalidCastException out of the engine.
2. Revoked proxy receiver: extracting the function through a live
Proxy.revocable wrapper, revoking, then calling with the revoked proxy
as this recursed with the nulled proxy target; the null passed the
reference cast and crashed with NullReferenceException on first member
access.
Both helpers now resolve their receiver through UnwrapReceiver, which
unwraps (nested) proxy chains with a loop, throws a JS TypeError
"Cannot perform '...' on a proxy that has been revoked" for revoked
proxies (realm taken from the proxy), and a JS TypeError
"Method '...' called on incompatible receiver" for non-wrapper receivers
(realm taken from the receiving ObjectInstance when available, falling
back to Throw.TypeErrorNoEngine for primitive receivers which the
interpreter materializes as a TypeError). Valid receivers - wrapper,
proxy-over-wrapper, proxy-over-proxy-over-wrapper - behave as before.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EsHuKuE4UihKZp5HYapDHE
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Two engine-crash modes in the
ObjectWrapperinterop helpers, both reachable from script:this— theSymbol.iteratorClrFunction and thelengthgetter are script-extractable (Object.getOwnPropertyDescriptor(clrList, 'length').get.call({})), and both hard-cast(ObjectWrapper) thisObject→ uncaughtInvalidCastException.NullReferenceExceptionon first member access.Both helpers now share an
UnwrapReceiverthat unwraps nested proxy chains iteratively, throwsTypeError: Cannot perform '[Symbol.iterator]' on a proxy that has been revokedfor revoked proxies (V8 wording), andTypeError: Method '…' called on incompatible receiverfor foreign receivers — including primitivethis, where no engine is reachable and the deferred-realm TypeError path is used (verified catchable andinstanceof TypeErrorfrom script).for...ofdirectly over a revoked proxy still throws from the proxy's own[[Get]]guard first, matching node — covered by test. Regression tests confirm iteration over single and nested proxies wrapping CLR lists still works.6 new tests; full Jint.Tests, PublicInterface, and test262
~Proxygreen.🤖 Generated with Claude Code
https://claude.ai/code/session_01EsHuKuE4UihKZp5HYapDHE