Gen: Pattern with Format Makes Validation Always Fail

[Unverified]

What version of ogen are you using?

github.com/ogen-go/ogen v1.14.0

Can this issue be reproduced with the latest version?

Yes

What did you do?

For snippet calling the client

openapi: 3.0.3
info:
  title: service
  description: Sample backend service
  version: 1.0.0
components:
  schemas:
    GenerateKeyRequestInput:
      type: object
      properties:
        encryptionKeyId:
          type: string
      required:
        - encryptionKeyId
    GenerateKeyResponse:
      type: object
      properties:
        encryptionKeyId:
          type: string
        privateKey:
          type: string
          format: base64
          pattern: ^$|^(?:[0-9a-zA-Z+/]{4})*(?:(?:[0-9a-zA-Z+/]{2}==)|(?:[0-9a-zA-Z+/]{3}=))?$
      required:
        - encryptionKeyId
        - privateKey
      additionalProperties: false
paths:
  /genkey:
    post:
      requestBody:
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/GenerateKeyRequestInput"
      responses:
        "200":
          description: Default Response
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/GenerateKeyResponse"
        default:
          description: Default Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  name:
                    type: string
                  message:
                    type: string
                required:
                  - name
                  - message
                additionalProperties: false

Calling the service with some input returns the following:

{
  "encryptionKeyId": "6d4cc1ae-3cd5-491b-9b60-53335a05fd1d",
  "privateKey": "bXJrLTAwMmIwOTE4MzZhMzRkY2FiZjU3OWM3MDNlMjNlMmVmOM4S9O1Q031IOv95lVj0O+swrsjoD1BO0AwSIQwyaTe8MQuGz/gMtriVeVcWjys7XaNy2Th7Vfw+qUzJPwn8Gj565nUD1wWKnEp+CYM02NlUIS72egYWmr9t4N+7x/aV3oxYtm6XPDJZRvYoTdco8A=="
}

(nothing here is confidential even if it might look like it, its just some throwaway values)

What did you expect to see?

That the call would succeed properly populating the go object.

What did you see instead?

error returned,

decode response: validate: invalid: privateKey (string: no regex match: ^$|^(?:[0-9a-zA-Z+/]{4})*(?:(?:[0-9a-zA-Z+/]{2}==)|(?:[0-9a-zA-Z+/]{3}=))?$)

[Unverified]

From what I can tell is happening, ogen is building up the []byte first. Then it runs though the pattern check on that resulting []byte which will always fail since that isn't going to be a base64 encoded string anymore.