Provide More Intuitive Behaviour for Launchd Services

[jacderida]

• b6fda30 fix: use correct logic for launchd restart policies

  For the OnSuccess case, the logic was actually inverted, so the service was restarting when the
  exit was not successful. This has now been corrected.

  The logic we were previously using for the OnSuccess case has now been applied to the OnFailure
  case, so we now support that scenario rather than emitting a warning saying we don't support it.

  A comment clarifies that when the SuccessfulExit construct is not used, this is effectively the
  Always policy.

• da5d943 feat: prevent launchd services starting when keepalive is used

  When the service definition includes the KeepAlive setting it causes services to automatically
  start when launchctl load is used. This is quite unintuitive and is not how services behave on
  other platforms.

  We now make use of the Disabled setting to prevent the service starting automatically and make it
  behave like service managers on other platforms. This is desirable when you want to add many
  services first and not have them all start at the same time, which is the case for our application.
  It also seems to be the behaviour most of our users expect and I personally think makes most sense.

• 652d31a chore(release): bump to version 0.10.0

[jacderida]

Hi Chip,

I realise this is another breaking change quite soon, but I really think it's worth it.

Due to the addition of the KeepAlive key, our macOS users encountered strange behaviour because Launchd was starting services as soon as they were added. This change makes the service manager behave like service managers on other platforms, i.e., the service will not start when it has been installed, and needs to be started explicitly as a separate step. I think the consistent cross-platform behaviour is desirable and the way it's done on other platforms just makes more sense anyway.

A little bug was also fixed.

It looks like I have some breaking tests here. Will try to investigate.

[jacderida]

I've now fixed the failing test case.

The Launchd test for running as sudo but with a specific user is still broken. Unfortunately I still don't have time to look into this at the moment, but do intend to when I get some free time.