Registering the OIDC login source makes an outbound HTTPS call - the CLI
fetches <issuer>/.well-known/openid-configuration to validate the
provider before writing the row. That URL is a swarm service name served
under the swarm CA, which the default system store has never heard of.
SSL_CERT_FILE was set on forgejo.service and not on
forgejo-sso-source.service, so the web service trusted the chain and the
registration one-shot did not. Same binary, same host, different unit.
The result was a 100% reproducible failure that no restart could fix:
nothing about restarting a unit gives it an environment variable it
never had. Every recorded run since the feature landed has failed with
x509: certificate signed by unknown authority.
The trust belongs to every process that makes the call, not to the
service that happens to be the obvious consumer.