Problem

z.fromJSONSchema() ignores description and default fields when the JSON Schema uses enum, const, or not: {} (never). This happens because these paths use early returns in convertBaseSchema() before reaching the metadata application block at the bottom of the function.

Minimal reproduction:

const schema = z.fromJSONSchema({
  enum: ["red", "green", "blue"],
  description: "A color value",
  default: "red",
});

schema.description; // undefined ❌ (expected "A color value")
schema.parse(undefined); // throws ❌ (expected "red")

Fixes #5732

Solution

Extract the metadata application (description + default) into a helper function applyBaseMetadata() and call it from each of the affected early-return paths:

• not: {} → z.never()
• enum → z.enum() / z.literal() / z.union()
• const → z.literal()

Tests

Added five new tests covering:

• description on enum schema
• description on const schema
• description on not: {} (never) schema
• default on enum schema
• default on const schema