[andrewingram]

Is there any interop between v3 and v4 schemas themselves? We have an enormous graph of hundreds (if not thousands) of Zod schemas, many inheriting or extending others. It's difficult to envisage us being able to do an incremental upgrade unless both versions can interact neatly.

But I am looking forward to seeing if this fixes our issue where in the worst case a 500 line schema file turns into 800,000 lines of generated types.

[colinmcd]

No, that kind of interop, especially static interop (assignability), would've been totally unworkable. Despite the length of the changelog, there are very few breaking changes to the user-facing API surface. It's mostly internal/structural changes and deprecations (most of which can be fixed with a find&replace).

Report back about that .d.ts issue. It should be far better. That kind of type explosion usually happens when TypeScript needs to infer function/method return types. Zod 4 uses isolatedDeclarations so this kind of thing shouldn't happen.

[paulddraper]

No. You will have errors if you try this.