The null example for a nullable field is ignored.

[BenoitClaveau]

The openapi({ example: null }} is not take into account.

const UserSchema = z
    .object({
        id: z.string().openapi({ example: "1212121" })
    })
    .openapi("User");

const UserInputSchema = z
    .object({
        name: z.string().openapi({ example: "John Doe" }),
        age: z.number().nullish().openapi({ example: null }) // <-- null
    })
    .openapi("User");

registry.registerPath({
    method: "post",
    path: "/users",
    summary: "Create a user",
    request: {
        body: {
            description: "Retrosynthesis request",
            content: {
                "application/json": {
                    schema: UserInputSchema
                }
            }
        }
    },
    responses: {
        200: {
            description: "Object with user data.",
            content: {
                "application/json": {
                    schema: UserSchema
                }
            }
        }
    }
});

Will generate:

  /users:
    post:
      summary: Create a user
      requestBody:
        description: Retrosynthesis request
        content:
          application/json:
            schema:
              allOf:
                - $ref: "#/components/schemas/User"
                - properties:
                    name:
                      type: string
                      example: John Doe
                    age:
                      type:
                        - number
                        - "null"
                  required:
                    - name
      responses:
        "200":
          description: Object with user data.
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/User"

The field "age" do not contains example like the field "name".

I expect to have this

 /users:
    post:
      summary: Create a user
      requestBody:
        description: Retrosynthesis request
        content:
          application/json:
            schema:
              allOf:
                - $ref: "#/components/schemas/User"
                - properties:
                    name:
                      type: string
                      example: John Doe
                    age:
                      type:
                        - number
                        - "null"
                       example: null
                  required:
                    - name
      responses:
        "200":
          description: Object with user data.
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/User"