Always set exit code

[asbjornu]

When GitVersion.exe is passed invalid arguments, it just outputs the help screen and returns 0 as its exit code. This just caused mayhem in a TeamCity build I tested out GitVersion in, because the whole build executed from start to finish without any step failing. Not even the NuGet Pack step failed, even though it used %system.GitVersion.FullSemVer% (which was just an empty string). You might blame JetBrains for this; the NuGet Pack build step should fail if its "Version" input is set to a variable and that variable returns null.

This PR fixes this problem by refactoring the Program class a bit so it invokes a Run() method that always returns an exit code and then always sets that exit code with Environment.Exit(exitCode).

I've also added a test that verifies the exit code in case of invalid arguments, which necessitated a little refactoring of the GitVersionHelper class.

PS: This PR also includes #280.

[gep13]

@asbjornu Did you see the note above about the failed build from the merge of this Pull Request. Can you take a look and get them fixed up? The contributors here likely won't accept the Pull Request until these are fixed.

[asbjornu]

Yea, @gep13, I noticed that. I've just registered an account and will fix the inspection errors ASAP. The problems noted are:

GitVersionExe.Tests: ArgumentBuilder.cs (5)

1. 16: Accessor 'Exec.get' can be made private
2. 18: Accessor 'ExecArgs.get' can be made private
3. 20: Accessor 'ProjectFile.get' can be made private
4. 22: Accessor 'ProjectArgs.get' can be made private
5. 28: Accessor 'AdditionalArguments.get' can be made private

[gep13]

Do you have a ReSharper license? If so, it is the same inspections that are being run on the TeamCity instance, i.e. you can test for them before making the Pull Request.

If not, there is a command line version of InspectCode, which is what ReSharper is using, that you can use:

choco install resharper-clt

Would get you them.

[JakeGinnivan]

From memory @distantcam made this change. Cam, what are your thoughts?

[asbjornu]

@gep13 Yea, I have ReSharper. But I don't see the same code inspection problems there as those TeamCity complained about. Anyway, the problems are fixed now so this should be safe to merge.

[JakeGinnivan]

@asbjornu you need to have solution wide analysis turned on to see those errors I think

[gep13]

@asbjornu you need to have solution wide analysis turned on to see those errors I think

Yes, this is exactly what I was going to say.

[asbjornu]

Yea, that setting is turned on through the GitVersion.sln.DotSettings file.

[JakeGinnivan]

@distantcam @SimonCropp @andreasohlund what are your thoughts on this change.

[andreasohlund]

Seems very resonable to me

[distantcam]

👍