Invalid state of a control in a control group hierarchy is not detected by the root control group #4994
Description
Consider the following code:
var fb:FormBuilder (injected)
var groupC : ControlGroup = fb.group({
groupB: fb.group({
controlA : ["",Validators.required]
})
})
var controlA : Control = <Control> groupB.find('groupB/controlA');
console.log("Control A valid:" + controlA.valid);
console.log("Group B valid:" + groupB.valid);
console.log("Group C valid:" + groupC.valid);
controlA.updateValue("");
console.log("Control A valid:" + controlA.valid);
console.log("Group B valid:" + groupB.valid);
console.log("Group C valid:" + groupC.valid);
In both cases controlA and groupB are invalid (to be expected) but groupC is valid (unexpected).
See the first bullet point in #4917 (comment) for what I think the bug is.