v9.1.0

Responder 9.1 makes Python return annotations complete HTTP response
contracts, from runtime validation through OpenAPI and generated clients.

Added

• Return annotations are now complete response contracts. Any supported
  Pydantic TypeAdapter shape — models, dataclasses, typed dictionaries,
  collections such as list[Item], unions, generic pagination models, and
  JSON scalars — drives runtime validation and serialization, OpenAPI response
  schemas, and generated-client types. Class-based-view method annotations and
  Flask-style tuple annotations infer the same way. Inferred str and bytes
  responses document and emit text/plain and application/octet-stream;
  other inferred contracts use application/json.
• Handlers may return bool, int, and float JSON scalars directly, in
  addition to the existing dictionaries, lists, strings, bytes, models, and
  dataclasses.
• responses={404: ErrorModel} now declares a status-specific response
  contract used for runtime validation and OpenAPI, including alternate
  success statuses. A response mapping may provide model alongside a custom
  description, headers, examples, or other OpenAPI metadata.

Changed

• Response contracts now validate the final success body after after-request
  hooks. A body whose shape or response channel contradicts its declared model
  fails closed with 500, including a list returned for a single-object model;
  response_model=False reliably disables inference and validation.
• Flask-style return tuples now require exactly (body, status) or
  (body, status, headers), a status integer from 100 through 599, and a
  header mapping. Malformed tuples fail clearly instead of being partially
  applied or silently ignored.
• Routes with unresolved or unsupported return annotations now log a focused
  registration warning with the response_model=False opt-out instead of
  silently dropping the inferred contract.

Fixed

• Informational, 204, 205, and 304 responses no longer send a body even
  if a handler returned or assigned one. Their inferred OpenAPI success
  responses omit content as well; HEAD continues to validate the
  corresponding GET response while sending headers only.