[proggeramlug]

Summary

Object.defineProperty on an existing own property must retain the attribute fields the descriptor omits (per ES OrdinaryDefineOwnProperty / ValidateAndApplyPropertyDescriptor) — they do not reset to the new-property false default. Perry previously defaulted every omitted attribute to false (and writable to has_accessor) on every define call, so converting an enumerable data property to a getter (or back to a value) silently dropped its enumerability / configurability.

This is a general spec-compliance bug, surfaced by zod v4 under perry.compilePackages (discussion #3438).

Root cause

zod's $ZodObject swaps the enumerable shape data property for a self-replacing getter via Object.defineProperty, then relies on { ...def } still spreading shape. Pre-fix, the first defineProperty(def, "shape", { get }) reset enumerable to false, so { ...def } dropped shape, normalizeDef's value.shape was undefined, and the slow-path object parser dereferenced shape[key]._zod on undefined:

TypeError: Cannot read properties of undefined (reading '_zod')

(Node never hits this because it takes the JIT new Function fastpass; Perry correctly throws on new Function, so zod's allowsEval gate is false and it falls to the slow path — which exposed the latent attribute bug.)

Fix

In both the object and closure define paths of js_object_define_property, capture the property's current effective attributes before any mutation (all-true when no descriptor side-table entry exists, matching the JS data-property default) and default each omitted descriptor field to the existing value. Brand-new properties still default to false, preserving prior behavior.

Validation

• New regression test test-files/test_issue_defineproperty_retain_attrs.ts — byte-matches node --experimental-strip-types. Covers value-only redefine, data→getter→value transitions, configurability retention, the new-property false control, and the exact zod shape-getter→spread pattern.
• With this fix, real zod v4 (perry.compilePackages: ["zod"]) object / nested-object / array / boolean / optional parsing now works and matches Node — previously every z.object(...).parse(...) crashed.
• cargo fmt clean.

Scope / follow-ups

This unblocks the core of zod object parsing. Two independent zod runtime bugs remain (separate from this change), to be filed/fixed as follow-ups:

• z.string().min(2) (checks) → ch._zod.onattach undefined
• safeParse on invalid input → error is not a function

Refs #3438, #793.