all { ComponentSelection selection ->
                            if (selection.candidate.version == '1.1') {
                                status11 = selection.metadata.status
                                branch11 = selection.getDescriptor(IvyModuleDescriptor).branch
                            } else {
                                selection.reject('not 1.1')
                            }

	switch r.operator {
	case selection.In, selection.Equals, selection.DoubleEquals:
		if !ls.Has(r.key) {
			return false
		}
		return r.hasValue(ls.Get(r.key))
	case selection.NotIn, selection.NotEquals:
		if !ls.Has(r.key) {
			return true
		}
		return !r.hasValue(ls.Get(r.key))
	case selection.Exists:
		return ls.Has(r.key)
	case selection.DoesNotExist:
		return !ls.Has(r.key)

			getRequirement("y", selection.Exists, nil, t),
		}, true},
		{Set{"y": ""}, &internalSelector{
			getRequirement("x", selection.DoesNotExist, nil, t),
			getRequirement("y", selection.Exists, nil, t),
		}, true},
		{Set{"y": ""}, &internalSelector{
			getRequirement("x", selection.NotIn, sets.NewString(""), t),
			getRequirement("y", selection.DoesNotExist, nil, t),
		}, false},

    dns[uriHost] = dns.allocate(1)
    var selection = routeSelector.next()
    val route = selection.next()
    routeDatabase.failed(route)
    routeSelector = newRouteSelector(address)
    selection = routeSelector.next()
    assertRoute(selection.next(), address, Proxy.NO_PROXY, dns.lookup(uriHost, 0), uriPort)
    assertThat(selection.hasNext()).isFalse()
    assertFailsWith<NoSuchElementException> {

            } else {
                Path projectPrefix = selection.getOriginalPath().getParent();
                ProjectState project = defaultBuild.getProjects().getProject(projectPrefix);
                return getSelectorForBuild(defaultBuild).getSelection(selection, project, selection.getOriginalPath().getName(), false);
            }

        failure.assertHasCause("java.lang.Exception: thrown from rule")
    }

    def "reports missing module when component selection rule requires meta-data"() {
        buildFile << """
configurations {
    conf {
        resolutionStrategy.componentSelection {
            all { ComponentSelection selection ->

                        componentSelection {
                            all { ComponentSelection selection ->
                                if ($descriptorArg != null) {
                                    println "A is evaluating \$selection.candidate"
                                    if (selection.candidate.version != "1.1") { selection.reject("Rejected by A") }
                                }
                            }

[[sec:resolving-variant-aware-errors]]
=== Variant Selection Errors

Sometimes a selection error happens at the <<variant_model.adoc#understanding-variant-selection,variant selection level>>.
Have a look at the <<variant_model.adoc#sec:variant-select-errors,dedicated section>> to understand these errors and how to resolve them.

include::sample[dir="snippets/dependencyManagement/customizingResolution-selectionRule/groovy",files="build.gradle[tags=targeted-component-selection]"]
====

Component selection rules can also consider component metadata when selecting a version.

        }
    }

    private static class WorkItem {
        final WorkSource.Selection<Object> selection;
        final WorkSource<Object> plan;
        final Action<Object> executor;

        public WorkItem(WorkSource.Selection<Object> selection, WorkSource<Object> plan, Action<Object> executor) {
            this.selection = selection;
            this.plan = plan;
            this.executor = executor;
        }
    }