String-to-model mapping fails with openapi v3

I am working on a project that generates typescript bindings from an openapi yml, but I am hitting unexpected schema validation errors.

ERROR: Schema violation: should NOT have additional properties (components > schemas > IListBuildsResponse > properties > builds > additionalProperties)
  additionalProperty: $ref

I performed this command:

npx autorest --input-file=clients/openapi.yml --typescript --output-folder=clients/typescript-autorest/src --v3 --add-credentials

I’ve reduced the yml to the following snippet to recreate the issue:

openapi: 3.0.1
info:
  title: test
  version: 0.0.1
  description: ''
paths:
  /test:
    post:
      operationId: some_api
      parameters: []
      responses:
        default:
          description: IBulkOperationResponse
          content:
            application/json:
              schema:
                $ref: >-
                  #/components/schemas/IListBuildsResponse
components:
  schemas:
    IBuildSummary:
      description: Public build summary returned to callers
      type: object
      properties:
        projectId:
          type: string
    IListBuildsResponse:
      type: object
      properties:
        builds:
          type: object
          additionalProperties:
            $ref: '#/components/schemas/IBuildSummary'

Expected behavior

Generation should be successful, given the spec: http://spec.openapis.org/oas/v3.1.0#model-with-map-dictionary-properties

Additional context

Full error:

   Loading AutoRest core      'C:\Users\jtfin\.autorest\@autorest_core@3.2.4\node_modules\@autorest\core\dist' (3.2.4)
INFORMATION: > Loading AutoRest extension '@autorest/typescript' (latest->6.0.0-alpha.20210309.1)
INFORMATION: > Loading AutoRest extension '@autorest/modelerfour' (4.15.456->4.15.456)
ERROR: Unrecoverable schema validation errors were encountered in OpenAPI 3 input files.
You can use --markOpenAPI3ErrorsAsWarning to keep mark as warning and let autorest keep going.
If you believe this the validation error is incorrect, please open an issue at https://github.com/Azure/autorest
NOTE: in the future this flag will be removed and validation error will fail the pipeline.
ERROR: Schema violation: should NOT have additional properties (components > schemas > IListBuildsResponse > properties > builds > additionalProperties)
  additionalProperty: $ref
    - file:///D:/repos/backend/clients/openapi.yml:44:6
ERROR: Unrecoverable schema validation errors were encountered in OpenAPI 3 input files.
You can use --markOpenAPI3ErrorsAsWarning to keep mark as warning and let autorest keep going.
If you believe this the validation error is incorrect, please open an issue at https://github.com/Azure/autorest
NOTE: in the future this flag will be removed and validation error will fail the pipeline.
ERROR: Schema violation: should NOT have additional properties (components > schemas > IListBuildsResponse > properties > builds > additionalProperties)
  additionalProperty: $ref
    - file:///D:/repos/backend/clients/openapi.yml:44:6
Process() cancelled due to failure
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[timotheeguerin]

Seems like there is an issue there as well.(flag is mark-oai3-errors-as-warnings but it will still throw the error and abort the run) Have a pr out fixing both issues and it will push a new version soon after it merges https://github.com/Azure/autorest/pull/4060

[Jtfinlay]

@timotheeguerin Works great 👍