core: routing - params inherited from parent state are not saved in the state history

[christophercr]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[X] Bug report  
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/NationalBankBelgium/stark/blob/master/CONTRIBUTING.md#got-a-question-or-problem

Current behavior

After navigating a state that inherits some params from his parent, the state history saved by the Routing Service does not contain such inherited params. This makes the navigateToPrevious() and the getStateTreeParams() methods to return wrong results since they rely on such state history.

Expected behavior

The state history saved by the Routing Service should contain also the inherited params so that they are also reflected in the results of the navigateToPrevious() and the getStateTreeParams() methods.

Minimal reproduction of the problem with instructions

• Declare 3 states:
  -- state A: define param1
  -- state B: child of state A and with no params defined (it will inherit the one from A)
  -- state C: child of state B and with no params defined (it will inherit the one from A)
  -- state D: completely isolated state (no parent)
• Navigate to A passing no params
• Navigate to B passing param1 = "some value"
• Navigate to C passing no params
• Navigate to D passing no params
• Navigate to previous (calling the navigateToPrevious() method)
• As a result of navigateToPrevious(), the end state should be C and param1 = "some value" should have been passed, since it is the inherited param from state B which was set on the transition to such state.

What is the motivation / use case for changing the behavior?

Accurate information stored in the state history for the navigateToPrevious() and the getStateTreeParams() methods.

Environment

Angular version: X.Y.Z
Stark version: 10.0.0-beta.0