Wrong URL used when executing the request from swagger ui when a server url starts with a variable

[brampouwelse-luminis]

Q&A (please complete the following information)

• OS: macOS
• Browser: chrome
• Version: 128
• Method of installation: npm
• Swagger-UI version: 5.17.14
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Example Swagger/OpenAPI definition:

---
openapi: "3.0.1"
info:
  title: "Random Yes/No"
  version: "1.0.0"
servers:
- url: "{server}/api"
  variables:
    server:
      default: "https://yesno.wtf"
paths:
  /:
    get:
      description: "Yes or no"
      responses:
        "200": 
          description: "OK"
          content:
            "application/json":
              schema:
                properties:
                  answer:
                    type: string
                  forced: 
                    type: boolean
                  image: 
                    type: string
                    format: uri

Describe the bug you're encountering

The wrong URL used when executing the request from swagger ui when a server url starts with a variable.

I feel this should work as the spec not having any validation issues and there is a similar example in the exaples section on this page https://swagger.io/docs/specification/api-host-and-base-path/ (see SaaS and On-Premise).

To reproduce...

Steps to reproduce the behavior:

1. Go to https://editor.swagger.io/
2. Paste the spec from the issue in the editor
3. Click "Try it out"
4. Click "Execute"

A request is now performed but it failed due to the request url getting prefixed with https://editor.swagger.io/

Expected behavior

A get request to https://yesno.wtf/api/

When manually replacing the {server} variable in the url with with the default value the hostname is not prefixed and the correct server url is used.