Yury and Michael were running into some issues with the component manager. The following sequence of steps: * RegisterFactory $CID, $CONTRACT_ID * UnregisterFactory $CID * IsContractIDRegistered $CONTRACT_ID can return true, which seems nonsensical. It makes a certain amount of sense, since UnregisterFactory doesn't know what contract ID corresponds to $CID. But we can do better. I know I've been bitten by this before and wasted a good amount of time figuring out what was going on. I think we can do better, and a try push with an experimental patch seems to not break anything horribly. I'll toss that up in a second.

We can have a valid nsFactoryEntry in the following cases: * We registered a known module; * We registered a factory (mModule will be null in this case); * We created a service via the factory. So one of these members must be valid if we still have a entry in the contract ID table that actually does interesting things.

Comment on attachment 8676950 [details] [diff] [review] try harder in IsContractIDRegistered to return a reasonable answer Worth checking whether this fixes bug 1193155.

Comment on attachment 8676950 [details] [diff] [review] try harder in IsContractIDRegistered to return a reasonable answer Review of attachment 8676950 [details] [diff] [review]: ----------------------------------------------------------------- Fixed bug 1193155 for me. (As well as bug 1193088, but it hard to tell if this or bug 1179262 fixed it)

Comment on attachment 8676950 [details] [diff] [review] try harder in IsContractIDRegistered to return a reasonable answer We should remove this API, but as long as we've got it it might as well do something useful.

Comment on attachment 8676950 [details] [diff] [review] try harder in IsContractIDRegistered to return a reasonable answer Approval Request Comment [Feature/regressing bug #]: bug 1179262 [User impact if declined]: can't toggle PDF.js on and off without restart (see bug 1193155) [Describe test coverage new/current, TreeHerder]: We have a few tests in-tree that exercise code around here, though not the specific additions that were made. [Risks and why]: Low risk. [String/UUID change made/needed]: None.

Comment on attachment 8676950 [details] [diff] [review] try harder in IsContractIDRegistered to return a reasonable answer Restarting is annoying for users; let's uplift this small fix to aurora and beta.

Marking as affected for 42+ since this seems to have been a problem since at least 40.