The method ConfigurationAdminImpl#getConfiguration(pid) dynamically sets the configuration's bundle location if it is null. However, it uses ConfigurationImpl#setStaticBundleLocation(location) in order to do so. This should be changed to set the dynamic location. Attached is a proposed patch.
The issue I observed, that lead me to this bug, was as follows:
1. Installed a number of factory configurations and the bundle (version 1.0.0, bundle location: jcrinstall:/apps/sample/install/bundle-1.0.0.jar) providing the service implementation (using SCR) via Sling's OSGi Installer
2. Uninstalled the bundle.
3. Installed the bundle (version 1.0.2, bundle location: jcrinstall:/apps/sample/install/bundle-1.0.2.jar)
After this, the factory configurations were not bound to the bundle any longer, because they were still bound to the no longer existing bundle location jcrinstall:/apps/sample/install/bundle-1.0.0.jar. This basically leaves stale configurations and a badly configured system.
While Sling's OSGi Installer handles updates without changing the bundle location normally, the above scenario differs in that instead of an update, there is an uninstall + re-install happening. The Configuration Admin Service Specification 1.3 clearly states (in 104.4.1 Location Binding): "When this dynamically bound bundle is subsequently uninstalled, the Configuration object's bundle location must be set to null again so it can be bound again later."
Note: in the patch I also changed the return type of ConfigurationImpl#tryBindLocation() from boolean to void. Before, it always returned true, so the return value is meaningless. I almost ended up using it in an if statement because of the return type, which made me believe that it returns true if the bundle location is set and false otherwise.