Q&A (please complete the following information)

• OS: macOS
• Browser: Chrome
• Version: 90.0.4430.93
• Method of installation: npm
• Swagger-UI version: [e.g. 3.47.1]
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Swagger/OpenAPI definition is not relevant for this issue bug here is a sample:

openapi: "3.0.1"
paths:
  /my-endpoint:
    get:
      operationId: getMyAwesomeEndpoint
      responses:
        "200":
          description: "Successful operation"

Swagger-UI configuration options:

import SwaggerUI from 'swagger-ui'
SwaggerUI({
  spec: spec,
  deepLinking: true,
  dom_id: '#swagger',
  plugins: [
    {
      wrapComponents: {
        info: (Original, { React, getComponents }) => (props) => {
          return React.createElement("div", null, [
            React.createElement("h3", {key: 1}, "Hello world! I am above the Info component"),
            React.createElement(Original, Object.assign({key: 2}, props)),
          ])
        }
      }
    },
    {
      wrapComponents: {
        info: (Original, { React, getConfig }) => (props) => {
          return React.createElement("div", null, [
            React.createElement(Original, Object.assign({key: 2}, props)),
            React.createElement("h4", {key: 1}, "Hello world! I am below the Info component") ,
          ])
        }
      }
    }
  ]
});

Describe the bug you're encountering

When multiple plugins are configured with wrapComponents entry on the same core component (info for example), only the last one is applied.
I was expected all of them to be applied in a chain pattern. They should end up being embedded according to where the Original component is applied.
So, in this example I should see both my titles before and after the info content.

Fix

I pinpointed the issue on system.js where plugins are combined.
As systemExtend() is called with an empty object for dest, we can't retrieve the existing components.

I was able to fix this issue by replacing .reduce(systemExtend, {}) with .reduce(systemExtend, toolbox.getComponents()) on system.js

WDYT ?