Fix verification error on ART runtime

[AdamClements]

Move monitor-enter outside try block, if the monitor-enter fails to acquire the lock, we should not attempt to release it.

[alexander-yakushev]

Nice! Have you found out why this is a problem on ART?

[AdamClements]

Yeah, the dex2oat compiler does additional static analysis and verification on the generated bytecode. JVM is fine with this, but ART is stricter and I think it is actually a clojure bug.

In debug mode it seems to do a few extra runtime checks too, it's thrown up a number of subtle type bugs in my own code that weren't an issue in dalvik and do actually run fine in release mode, but debug mode flags them up.

[alexander-yakushev]

OK, thanks for clarification! Merged.

I don't know if it's Clojure bug, to me putting monitor-enter call inside try seems reasonable (although I don't know if monitor-enter can throw an exception). Could you possibly submit an issue to JIRA?

[AdamClements]

Already done: http://dev.clojure.org/jira/browse/CLJ-1472

And it's standard practice when locking something and releasing it in a finally, not to include the lock in the try, or you'd be unlocking something you haven't yet locked if the initial locking fails, which is broken behaviour.

[alexander-yakushev]

Makes sense, let's see what they say on JIRA.