error "is not a valid api" trying to add subscriber to a bug

It's reproducible.

Is it connected to this team somehow having a space in its name? How can that happen?

The team is here: <https://bugs.edge.launchpad.net/~mysql+canonical-support-bazaar> and does apparently indeed have a space escaped to plus.

If there's a workaround it would be helpful.

Can you middle click or right click and open a new tab or some other such alternate click pattern to get to the actual subscribe someone else page? Does that page work?

This is related to bug 382018 and likely a fix for one will get the other. In both cases, characters not normally used in URIs are used in usernames. I would have thought we would have prevented spaces, plus signs, etc. since usernames are used in URLs, but I should have checked to confirm rather than assuming.

Yes, right-clicking then choosing 'open in new window' did give me the non-ajax form from which I could add them.

I didn't try subscribing them from email but that might also have worked. Or it might not, depending on how the email syntax handles spaces.

Perhaps if spaces are not intended to be supported but people have created them those teams should be migrated?

I suspect what may have happened is this: the web ui forbids spaces in names. However it also forbids names containing the word "canonical". If someone asked a LOSA to create that team by hand, they may have bypassed the checks.

The API problem mentioned here is fixed as of devel r8845. There are some issues that remain when updating the DOM after subscribing directly or subscribing a team you can unsubscribe, which relates to bug 382018. I've got a branch in the works to fix the remaining problems and have also opened bug 399348 against lp-registry, since we shouldn't be using + in user names anyway.