Hacktoberfest 2026: los issues que los mantenedores marcaron para octubre, abiertos y aptos para principiantes. Explorar issues de Hacktoberfest

Bug Report: `default` for array params (`type: [String]`) is incorrectly placed inside `items`

Abierto
  • ¿Algo no está bien?
#950 2 comentarios 1 reacción 0 asignados Ver en GitHub

Los mantenedores suelen responder en 1 día

Nadie ha tomado este issue todavía.

Evaluación

Dificultad
3/5
Tiempo estimado
1-2 días
Aptitud para principiantes
45/100
Tipo de issue
Error
Claridad
Bastante claro
Estado de actividad
Estancado
Stack tecnológico
openapi, ruby
Área
api, documentation

Línea de trabajo

Start by reproducing the array parameter declaration from the issue and inspect the schema-generation path that places defaults on array items. Compare the generated OpenAPI output with the expected array-level default, then verify the corrected schema against the Swagger Editor example and related behavior in PR #651.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

Summary

When using the following parameter declaration in Grape:

optional :dns_servers, type: [String], desc: 'DNS servers', allow_blank: false, default: ["8.8.8.8", "8.8.4.4"]

grape-swagger generates an OpenAPI schema where the default value is incorrectly placed inside items, instead of being set at the array level. This causes the field to be interpreted as a nested array ([[value]]) in Swagger tools and breaks the expected structure.

🔍 Current Behavior (Incorrect)

Generated OpenAPI snippet:

dns_servers:
  type: array
  items:
    type: string
    default: ["8.8.8.8", "8.8.4.4"]  # ❌ incorrect placement — default on items must be a single value, not an array

⚠️ Swagger Editor interprets this as:

"dns_servers": [
  ["8.8.8.8", "8.8.4.4"]
]

Which is not the intended behavior, and breaks compatibility with clients, documentation, and tools.

✅ Expected Behavior

The correct OpenAPI output should look like this:

dns_servers:
  type: array
  items:
    type: string
  default:
    - "8.8.8.8"
    - "8.8.4.4"

This correctly documents a default array of strings, not a nested array of arrays.

🧪 Minimal Reproducible Example (Swagger Editor — OpenAPI 2.0 - https://editor.swagger.io)
swagger: "2.0"
info:
  title: DNS Servers Example
  version: "1.0"
paths:
  /example:
    post:
      parameters:
        - in: body
          name: postV1Organization
          required: true
          schema:
            type: object
            properties:
              dns_servers:
                type: array
                items:
                  type: string
                  default: ["8.8.8.8", "8.8.4.4"]  # ❌ incorrect — invalid type, causes nested array
      responses:
        200:
          description: OK

✅ Correct version for comparison:

dns_servers:
  type: array
  items:
    type: string
  default:
    - "8.8.8.8"
    - "8.8.4.4"
📚 Specification Insights (OpenAPI & JSON Schema)

  • OpenAPI 3.0 Schema Object:

    The default value represents what would be assumed by the consumer of the input if one is not provided. It MUST conform to the defined type for the schema object.

  • Swagger 2.0 Items Object:

    The value MUST conform to the defined type for the data type.

  • JSON Schema - enum:

    The instance MUST be equal to one of the values in the array.

  • JSON Schema - default:

    It is RECOMMENDED that a default value be valid against the associated schema.

🔎 Why this matters
  • Placing default inside items implies a per-item default, which is not meaningful for array parameters.
  • Putting an array value as the default inside items (which expects a scalar) leads to nested arrays and invalid schemas.
  • This issue causes confusion in docs, misbehavior in tools, and breaks conformity with OpenAPI semantics.
🔗 Related
📦 Version Info
  • ruby: 3.3.4
  • grape: 2.3.0
  • grape-swagger: 2.1.2

💡 Suggestion: when generating schemas from type: [String] with a default, grape-swagger should ensure the default is set at the array level — not inside items, and that its type conforms to OpenAPI expectations.

Lenguaje dominante
Ruby
Estrellas
1.1k
Forks
478
Merge medio
7 h 25 min
PR fusionados (30 d)
1

Preparar el entorno

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

Más de ruby-grape/grape-swagger

Todos los issues de ruby-grape/grape-swagger

Issues similares

Más issues de Ruby

Recibe los nuevos issues en tu correo

Un resumen breve de issues de GitHub para principiantes.