code review 89750043: ogle/program/server: clarify ordering of evaluation whe...

ogle/program/server: clarify ordering of evaluation when ptraceRun
wraps a closure that 'returns' more than just an error.

I don't think this changes the actual behavior with the gc compiler,
but a different compiler might not optimize the "return foo" part
as a no-op, in:
func f() (foo int, err error) {
        etc
        return foo, <-s.ec
}
and then it's possibly racy whether foo is evaluated before or after
the channel receive.

[nigeltao, 2014-04-21 02:14:14]

Hello r@golang.org,

I'd like you to review this change to
https://code.google.com/p/ogle

[r, 2014-04-21 06:41:06]

LGTM

[nigeltao, 2014-04-26 15:27:08]

*** Submitted as https://code.google.com/p/ogle/source/detail?r=0418e9debffa ***

ogle/program/server: clarify ordering of evaluation when ptraceRun
wraps a closure that 'returns' more than just an error.

I don't think this changes the actual behavior with the gc compiler,
but a different compiler might not optimize the "return foo" part
as a no-op, in:
func f() (foo int, err error) {
        etc
        return foo, <-s.ec
}
and then it's possibly racy whether foo is evaluated before or after
the channel receive.

LGTM=r
R=r
https://codereview.appspot.com/89750043