Attempt to fix issue #59

[darkvertex]

This is not really working quite right yet, but I'm giving it a try. Advice, corrections, tips all welcome.

This is my testing scenario which generates potato_0 through potato_3 and only the last one is activated:

import pyblish.api
import pyblish_lite


class FakeCollector(pyblish.api.ContextPlugin):
    order = pyblish.api.CollectorOrder

    def process(self, context):
        for i in range(4):
            name = 'potato_{0}'.format(i)
            inst = context.create_instance(
                name, label=name, family='vegetable')
            inst.data['icon'] = 'male'
            inst.data['optional'] = True

            # Leave them all OFF except the last one:
            inst.data['publish'] = name == 'potato_3'


class FakeValidator(pyblish.api.InstancePlugin):
    order = pyblish.api.ValidatorOrder
    families = ['vegetable']

    def process(self, instance):
        # raise pyblish.api.ValidationError('Boo!')
        pass


def setupPlugins():
    pyblish.api.deregister_all_plugins()
    pyblish.api.deregister_all_paths()
    pyblish.api.register_plugin(FakeCollector)
    pyblish.api.register_plugin(FakeValidator)


def startUI():
    setupPlugins()
    pyblish.api.register_host("python")
    window = pyblish_lite.show()


startUI()

Previous to this PR, if you untick potato_3 and tick any of the others, potato_3 will get a green outline, meaning it processed, despite being deactivated.

With the code as it stands at the moment, if I uncheck potato_3, it does not get evaluated, but neither does the others. It seems I made the whole FakeValidator skip instead of the individual instance. I must've done something wrong somewhere.

[mottosso]

Thanks for this @darkvertex. I can't spot what's gone wrong from a quick glance, but if it helps you're welcome to remove the iterator altogether, and with it the ability to "pause" which I think is the thing making the most fuss. It has never really worked out that well, and likely doesn't provide much value either.