Generated swagger.yaml is corrupted in openapiv2 v2.17.0+: Path item becomes string instead of object

[qawatake]

🐛 Bug Report

Starting from version v2.17.0 of openapiv2, the generated swagger.yaml file is corrupted. Specifically, where the path item should be an object, it has become a string.

To Reproduce

Execute the following using openapiv2 v2.17.1:

protoc -I . --openapiv2_out ./gen \
    --openapiv2_opt=output_format=yaml \
    your/service/v1/your_service.proto

For this, let's assume your_service.proto is as follows:

syntax = "proto3";
package your.service.v1;

import "google/api/annotations.proto";

option go_package = "github.com/yourorg/yourprotos/gen/go/your/service/v1";

message StringMessage {
  string value = 1;
}

service YourService {
  rpc Echo(StringMessage) returns (StringMessage) {
    option (google.api.http) = {post: "/api/echo"};
  }
}

Expected behavior

The file generated with openapiv2 v.2.6.2 is as follows:

swagger: "2.0"
info:
  title: your/service/v1/your_service.proto
  version: version not set
tags:
  - name: YourService
consumes:
  - application/json
produces:
  - application/json
paths:
  /api/echo:
    post:
      operationId: YourService_Echo
      responses:
        "200":
          description: A successful response.
          schema:
            $ref: '#/definitions/v1StringMessage'
        default:
          description: An unexpected error response.
          schema:
            $ref: '#/definitions/rpcStatus'
      parameters:
        - name: value
          in: query
          required: false
          type: string
      tags:
        - YourService
definitions:
  protobufAny:
    type: object
    properties:
      '@type':
        type: string
    additionalProperties: {}
  rpcStatus:
    type: object
    properties:
      code:
        type: integer
        format: int32
      message:
        type: string
      details:
        type: array
        items:
          type: object
          $ref: '#/definitions/protobufAny'
  v1StringMessage:
    type: object
    properties:
      value:
        type: string

Actual Behavior

The file generated with openapiv2 v2.17.1 is as follows. The path item corresponding to /api/echo has turned into a string.

swagger: "2.0"
info:
  title: your/service/v1/your_service.proto
  version: version not set
tags:
  - name: YourService
consumes:
  - application/json
produces:
  - application/json
paths:
  /api/echo: |
    post:
        operationId: YourService_Echo
        responses:
            "200":
                description: A successful response.
                schema:
                    $ref: '#/definitions/v1StringMessage'
            default:
                description: An unexpected error response.
                schema:
                    $ref: '#/definitions/rpcStatus'
        parameters:
            - name: value
              in: query
              required: false
              type: string
        tags:
            - YourService
definitions:
  protobufAny:
    type: object
    properties:
      '@type':
        type: string
    additionalProperties: {}
  rpcStatus:
    type: object
    properties:
      code:
        type: integer
        format: int32
      message:
        type: string
      details:
        type: array
        items:
          type: object
          $ref: '#/definitions/protobufAny'
  v1StringMessage:
    type: object
    properties:
      value:
        type: string

Your Environment

Mac OS - Darwin Kernel Version 21.3.0: Wed Jan 5 21:37:58 PST 2022; root:xnu-8019.80.24~20/RELEASE_X86_64 x86_64

[qawatake]

I think it can probably be fixed like this ↓. However, this will cause existing tests to fail. I suspect it's a bug in go-yaml v3.

qawatake@146e09a

$ go test -v -run YAMLIndent ./protoc-gen-openapiv2/internal/genopenapi
=== RUN   TestGeneratedYAMLIndent
2023/08/30 22:27:50 ERROR: no message found: Status
    generator_test.go:251: failed to generate targets: failed to encode OpenAPI for exampleproto/v1/exampleproto.proto: yaml: line 8: did not find expected key
--- FAIL: TestGeneratedYAMLIndent (0.00s)
FAIL
FAIL    github.com/grpc-ecosystem/grpc-gateway/v2/protoc-gen-openapiv2/internal/genopenapi    0.219s
FAIL

[jruckert]

Can confirm we are experiencing this also.

[johanbrandhorst]

Thanks for reporting this issue. Please feel free to submit a PR with the proposed change and we can work out exactly what if any test changes will need to be made. Thank you!