Jellyfin's UserManager constructor-injects every IAuthenticationProvider, so
building IUserManager forced SharedAccountAuthenticationProvider to be built
first. That provider eagerly required IGroupService and IDynamicGroupService,
both of which need IUserManager, and the container refused to start the server
with "a circular dependency was detected".
Take the two group services as Lazy<T> and dereference them at authentication
time instead. Nobody can log in before the host is up, so the deferred lookup
is always safe. Microsoft's container has no built-in Lazy<T> support, hence
the explicit factory registrations.
The accompanying test builds the service graph through a stand-in that mimics
UserManager's constructor shape and validates it on build, so a reintroduced
cycle fails in CI rather than at server startup.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dtourolleandClaude Opus 5
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