Undocumented (?) change to `z.any()` object property behavior in v4.4.0

[lynnntropy]

Since v4.4.0, object properties defined as z.any() are now treated as required (i.e. the object will fail to parse if the property is unset). The release notes say this is now the expected behavior for z.undefined(), but don't mention z.any(), so I assume this is unintended?

Reproduction: v4.3.6, v4.4.0

[pullfrog]

Reproduced. z.object({ a: z.any() }).parse({}) throws expected nonoptional on 4.4.x but succeeded on 4.3.x. Same regression class as #5993 — z.any() doesn't set _zod.optin = "optional", so the missing-key check fires before the entry's schema runs. Posted a self-contained repro and workaround on the issue.

import { z } from "zod";

const schema = z.object({ a: z.any() });

schema.parse({});            // 4.3.x → ok; 4.4.x → ZodError: expected nonoptional at "a"
schema.parse({ a: undefined }); // ok in both
schema.parse({ a: 1 });         // ok in both

Workaround: z.any().optional() (which sets the optin flag).

#5997

  ^{｜ View workflow run ｜ via Pullfrog ｜ Using Claude Opus ｜ 𝕏}