Failing calls to the Shell now return a proper exit code

[HavokInspiration]

Refs #215

[thinkingmedia]

Have you tested this? I've found that cake ignores the return value for main in a shell. I had to use exit($value) to get my shells to return a value.

[HavokInspiration]

It does. See this.
The key is to return a bool (true if success, false if error) because of how the ShellDispatcher treats the response of the inner method call.

You can clone the branch, run a shell without error and run echo $? it should return 0.
Create an error (remove an entry in the phinxlog for instance and re-run a migrate call) and run echo $? it should return 1.

And given than shell can be dispatched from other shell, using exit is not an option. Whether or not to early exit the entire shell call should come from the user and not the plugin itself.

[thinkingmedia]

Ah, okay. I was trying to have the shell return an exit code as a value (i.e. how many records exist). Which doesn't work because ShellDispatcher mutates the return value to 0 or 1.

I don't think that will effect your changes.

[HavokInspiration]

I don't think that will effect your changes.

What do you mean ?

[HavokInspiration]

Anyone to give this a quick review ?

[dereuromark]

Looks good to me.