fix for empty output from git-plan command

[jweibel22]

We're seeing a sporadic issue when building projects with shuttle plans. Occasionally the tag of the docker image has an empty shuttlePlanHash (so the image tag would end up something like "master-e71d796c6e-")

This happens because the planHash() function in the shuttle.groovy file returns empty output. The function generates that output using './shuttle --skip-pull git-plan rev-parse HEAD'.

When looking at the source code of RunGitPlanCommand it looks like it might suffer from a race condition and exit prematurely before printing the output.

I had a look at the streaming example from https://github.com/go-cmd/cmd/blob/master/examples/blocking-streaming/main.go and basically copy-pasted that.

[jweibel22]

I have no idea why the build is failing

[Crevil]

Sweet 🙌 I’ll look into the build 👍

[jweibel22]

this still needs a bit of love :-)
looks like it blocks forever because the stdOut and stdErr channels are not closed for some reason.
I'll have another look tomorrow

[jweibel22]

Turns out the issue with the output channels not getting closed has been brought up here:
go-cmd/cmd#26
It has been resolved and fixed in version v1.2.0 (and I have verified this)

I can think of 3 options

1. Bump version of go-cmd to v1.2.0 (just a minor version difference so probably no breaking changes)
2. Disable streaming (streaming is beneficial when executing "long running" commands, I'm not sure if we're calling any git commands that are actually long running, where waiting for output to be printed is an actual issue)
3. Close the stdOut and stdErr channels ourselves when the command has finished.

[Crevil]

Let's just bump the dep instead of changing the functionality.

Further more, as it has been fixed upstream, let's not monkey patch it locally 🤓

[Crevil]

Great. I'll cut a release right away 🥇