Comment 9 for bug 286906

The main issue here is one of policy.

In short, people developing apps for Ubuntu want SpiderMonkey to grow up and start acting like a real library. That means we commit to keeping libmozjs's ABI backward compatible within each stable release branch (such as mozilla-1.9.1).

Either these users would be a net win for us or a net distraction. I encourage discussion on this point. On the whole I think diverse use of libmozjs is a net win, potentially a huge win.

What is the cost of having such a compatibility policy? Two things.

1. Mainly, everyone on the JS team would just need to be aware of it when writing patches that might be backported to a stable branch. Branch owners/release drivers should agree to the policy too. ABI backward compatibility means we can't delete a "friend API" function or change its signature or semantics incompatibly in a stable branch.

2. Second, there's the cost of actually doing releases, which seems small but deserves some consideration given what happened with 1.8 (in short, with tremendous effort I managed to shove a release candidate out the door, but never managed a final release). I think we can minimize this cost just by saying "whatever ships in gecko is an official SpiderMonkey release".

Please comment.