Swagger UI is generating incorrect Example Value for a nullable property in openapi 3.1.1

[ctyar]

Q&A (please complete the following information)

• OS: Windows 10
• Browser: Firefox
• Version: 136.0.4
• Method of installation: https://editor-next.swagger.io/
• Swagger-UI version: https://editor-next.swagger.io/
• Swagger/OpenAPI version: latest/ OpenAPI 3.1.1

Content & configuration

Example Swagger/OpenAPI definition:

{
  "openapi": "3.1.1",
  "info": {
    "title": "Playground | v1",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:5150"
    }
  ],
  "paths": {
    "/todos": {
      "post": {
        "tags": [
          "TodoEndpoints"
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/TodoRequest"
              }
            }
          },
          "required": true
        },
        "responses": {
          "201": {
            "description": "Created"
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "NullableOfPriority": {
        "enum": [
          "Low",
          "Medium",
          "High",
          "Critical",
          null
        ]
      },
      "TodoRequest": {
        "required": [
          "description",
          "priority"
        ],
        "type": "object",
        "properties": {
          "description": {
            "type": [
              "null",
              "string"
            ]
          },
          "dueDate": {
            "type": [
              "null",
              "string"
            ],
            "format": "date-time"
          },
          "priority": {
            "$ref": "#/components/schemas/NullableOfPriority"
          },
          "tags": {
            "type": [
              "null",
              "array"
            ],
            "items": {
              "type": "string"
            }
          }
        }
      }
    }
  },
  "tags": [
    {
      "name": "TodoEndpoints"
    }
  ]
}

Describe the bug you're encountering

Swagger UI produces nulls for Description and DueDate properties in the Example Value section:

To reproduce...

Steps to reproduce the behavior:

1. Go to https://editor-next.swagger.io/
2. Import the OpenAPI specification above
3. Check the Example Value

Expected behavior

The following for the example value:

Additional context or thoughts

In the specification above, if we change the order of members in the type array from:

"description": {
            "type": [
              "null",
              "string"
            ]
          },

To:

"description": {
            "type": [
              "string",
              "null"
            ]
          },

Swagger UI will produce the correct example value.

[glowcloud]

Addressed in #10390.

[glowcloud]

Released as https://github.com/swagger-api/swagger-ui/releases/tag/v5.20.4