Springdoc + OpenId Connect = missing client_id from Swagger request - spring-boot

Question

I am integrating a Spring Boot application with OIDC. The customer has an OIDC manifest file, at https://example.biz/.well-known/openid-configuration, which is redacted as displayed later.
Problem
When I attempt to authenticate via Swagger, the authorization endpoint complains that a parameter is missing. I could see that Swagger does not send the client_id parameter in (it's actually empty).
Please note, I expect that 99% of the configuration is handled by Springdoc after the OIDC configuration URL.
Question
Why doesn't Springdoc/Swagger OIDC setup work according to the existing setup and OIDC manifest?
Set up
OIDC manifest I can retrieve from authorization endpoint
{
"client_id": "the-clientid",
"issuer": "https://...",
"authorization_endpoint": "https://...",
"token_endpoint": "https://...",
"userinfo_endpoint": "https://...",
"jwks_uri": "https://...",
"end_session_endpoint": "https://...",
"registration_endpoint": null,
"scopes_supported": [
"openid"
],
"response_types_supported": [
"token",
"id_token",
"id_token token"
],
"response_modes_supported": [
"form_post",
"fragment"
],
"grant_types_supported": [
""
],
"subject_types_supported": [
"pairwise"
],
"id_token_signing_alg_values_supported": [
"RS256"
],
"token_endpoint_auth_methods_supported": [
"client_secret_basic"
],
"claims_supported": [
"sub",
"iss",
"aud",
"exp",
"iat",
"auth_time",
"nonce"
]
}
I import this scheme using Springdoc's #SecurityScheme annotation
#ConditionalOnProperty(...) // I can switch between basic (dev) and oidc authentication (test, uat, prod)
#SecurityScheme(
name = "secured",
type = OPENIDCONNECT,
openIdConnectUrl = "${oidc-url}/.well-known/openid-configuration" //Parameterized URL works here
)
public class OidcConfiguration {
}
Swagger displays me the Authorize button on top of the page.
However, when I see the generated Swagger OpenAPI v3 schema, it looks like the following
{
"openapi": "3.0.1",
"info": {
"title": "API",
"version": "v1"
},
"servers": [
{
"url": "http://localhost:8080",
"description": "Generated server url"
}
],
"paths": {
"/api/v1/.....": {
"patch": {
"tags": [
"...."
],
"operationId": "...",
"responses": {
"200": {
"description": "OK"
}
},
"security": [
{
"secured": []
}
]
}
},
"/health.check": {
"get": {
"tags": [
"probe-controller"
],
"operationId": "healthCheckProbe",
"responses": {
"200": {
"description": "OK",
"content": {
"*/*": {
"schema": {
"type": "boolean"
}
}
}
}
},
"security": [
{
"open": []
}
]
}
}
},
"components": {
"securitySchemes": {
"secured": {
"type": "openldConnect",
"openldConnectUrl": "https://...."
}
}
}
}
As you can see, the JSON file points to the remote OIDC configuration, and Swagger retrieves it.
But when I click on the Authentication button, I can see in the popup
secured (OAuth2, )
OpenId Connect URL: https://.....
Flow:
Scopes (select all, select none)
[ ] openid
According to this, I am not prompted with any client id. Clicking on Authorize opens a new window where I can't debug the original URL, as I am immediately redirected and DevTools is not open yet.
But after login request, I could see that the next URL displays ?client_id=&.....
If I manually navigate the URL with the client ID set, I can be redirected.
I also tried to set springdoc.swagger-ui.oauth.clientId=some client id according to linked issue, but it didn't display the input box.