IssueTracker

Component used: Navigation
Version used: 1.0.0-alpha02
Devices/Android versions reproduced on: Emulator API 27

Expected result:

When executing a navigation action with Clear Task flag set (either in the editor or in NavOptions) with an activity as a target, the target activity becomes the root (and the sole activity) of the current task and pressing back button shouldn't allow comming back to the source activity.

Before: [A]
Action: A -> B
After: [B]

Actual result:

The target activity is just added to the back stack, so popping navigates back to the source activity.

Before: [A]
Action: A -> B
After: [A, B]

I think this is caused by setting only Intent.FLAG_ACTIVITY_CLEAR_TASK, without Intent.FLAG_ACTIVITY_NEW_TASK.

ActivityNavigator, lines 117-119:

if (navOptions != null && navOptions.shouldClearTask()) {
   intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
}

According to the docs:

"If set in an Intent passed to Context.startActivity(), this flag will cause any existing task that would be associated with the activity to be cleared before the activity is started. That is, the activity becomes the new root of an otherwise empty task, and any old activities are finished. This can only be used in conjunction with FLAG_ACTIVITY_NEW_TASK."