Traced the exact "Cannot read properties of undefined (reading
lifeCycleAbortSignal)" error by fetching the target server's actual
viewmanager.js and pluginmanager.js directly (both are unauthenticated
static JS) instead of guessing further from docs.
Root cause: Emby's modern ViewManager (v4.10.0.40) only creates a
view.controller - required before it calls any lifecycle method on
the view - when the view's root element has a data-controller
attribute resolving to an AMD module via
pluginManager.getConfigurationResourceUrl(). partyPage.html never had
one (only the legacy data-role="page" attribute), so
newView.controller stayed undefined and getResumeOptions crashed
reading a property off it. configPage.html (the admin settings page)
apparently survives without this because dashboard pages go through a
different/older loading path.
Fix: added data-controller="__plugin/WatchPartyRoomController" to
partyPage.html, and a third PluginPageInfo/embedded resource
(partyPageController.js) - a minimal AMD module for it to resolve to.
ViewManager mixes in baseview.js's onResume/onPause/lifeCycleAbortSignal
automatically since this controller doesn't define its own, so it only
needs to exist.
Also checked (live JS probe, not a guess): pluginmanager.js has a
hardcoded plugin-id allowlist (allowPluginPages), but it's bypassed
whenever appHost.supports('restrictedplugins') is falsy - confirmed
falsy here, so it isn't blocking anything on this server's web client.
docs/architecture.md updated with the full trace for posterity.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Nicolas
f25f719e5f