The Jint upgrade that follows re-arms three engine-wide inline cache gates.
Each of those changes is only worth making if it is observably identical, so
pin the behaviour first, against Jint 4.8.0:
- null propagation: undeclared identifier reads, nullish property chains,
calls over a nullish base, calls of a non-callable member (which return
the base), and that ordinary member reads/calls are unaffected;
- enum values crossing into script as their member name, including a
[Flags] combination and an enum member of a wrapped CLR object;
- JSON objects projected into script: own key order, JSON.stringify,
for..in, mutation (add/replace/delete) and the round trip back to
JsonValue;
- content field objects: `in`, hasOwnProperty, propertyIsEnumerable,
Object.keys, spread, JSON.stringify, and that all of them follow
deletes and additions;
- the context object: key enumeration, `in`, typeof per value, reads,
write-through to ScriptVars and delete.
All 156 tests in Operations/Scripting pass unchanged on 4.8.0.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016uV6H9cTntzsoKiaJRBn4f
Marko Lahma
2fa24b5a5b