Data Race in child/child.go

[eikenb]

I was testing another feature and discovered a data race had slipped into the child/ code in the last commit. It is a race between line...

consul-template/child/child.go

Line 277 in dc274bc

err := cmd.Wait()

And line...

consul-template/child/child.go

Line 376 in dc274bc

if c.cmd.ProcessState != nil {

The cmd.Wait() in start() is run in a goroutine and it updates cmd.ProcessState internally. Which that c.cmd.ProcessState access in kill() races with.

Note that triggering this race in production would be hard, which is why I think no one ran into it (or at least reported it).

I'm working on a fix which I will be pushing up a PR for shortly, but wanted an issue for the record.