subwatcher errors are now propagated as discussed

subwatcher errors are now propagated as discussed

(I also dropped a couple of watcher fields that were only used in single
methods)

https://code.launchpad.net/~fwereade/juju-core/propagate-subwatcher-errors/+merge/111214

(do not edit description out of merge proposal)

[fwereade, 2012-06-20 12:48:55]

Please take a look.

[niemeyer, 2012-06-20 12:59:44]

LGTM.. only suggestions for the docs:

https://codereview.appspot.com/6298097/diff/1/state/watcher.go
File state/watcher.go (left):

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#oldcode390
state/watcher.go:390: emittedValue bool
Good catch.

https://codereview.appspot.com/6298097/diff/1/state/watcher.go
File state/watcher.go (right):

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode34
state/watcher.go:34: // it to shut down in response. This is intended to ensure
that closed
s/shut down/die/; that's the terminology we've been using with tombs. Please
review the doc as it has several occurrences.

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode37
state/watcher.go:37: // if it has shut down "cleanly", there's a logic error
somewhere.
s/has shut down "cleanly"/was killed with a nil error, which indicates a clean
stop, /

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode41
state/watcher.go:41: panic("subwatcher was shut down")
s/shut down/stopped cleanly/

[fwereade, 2012-06-20 13:10:09]

*** Submitted:

subwatcher errors are now propagated as discussed

(I also dropped a couple of watcher fields that were only used in single
methods)

R=niemeyer
CC=
https://codereview.appspot.com/6298097

https://codereview.appspot.com/6298097/diff/1/state/watcher.go
File state/watcher.go (right):

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode34
state/watcher.go:34: // it to shut down in response. This is intended to ensure
that closed
On 2012/06/20 12:59:44, niemeyer wrote:
> s/shut down/die/; that's the terminology we've been using with tombs. Please
> review the doc as it has several occurrences.

Done.

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode37
state/watcher.go:37: // if it has shut down "cleanly", there's a logic error
somewhere.
On 2012/06/20 12:59:44, niemeyer wrote:
> s/has shut down "cleanly"/was killed with a nil error, which indicates a clean
> stop, /

Done.

https://codereview.appspot.com/6298097/diff/1/state/watcher.go#newcode41
state/watcher.go:41: panic("subwatcher was shut down")
On 2012/06/20 12:59:44, niemeyer wrote:
> s/shut down/stopped cleanly/

Done.