Allow `state.push` with the same state that the app is in

[Seldom-SE]

What problem does this solve or what need does it fill?

Currently, calling state.push on a state that the app is currently in yields an Err(StateError::AlreadyInState). This is a problem for devs who want to stack multiple states of the same variant. In my case, I have a GameState::Menu state that I want to stack directly on top of each other, since I have menus that lead to other menus. I have on_enter and on_exit systems that I want to run for each of my menus. My menus are determined at runtime, so I cannot add a new GameState variant for every menu in the game. My current workaround involves adding a GameState::Buffer between each GameState::Menu. My GameState::Buffer immediately pushes a given state in on_enter, and immediately pops in on_resume. Removing the error from state.push would let me remove this workaround and help to clean up my game's logic.

What solution would you like?

I would like the return Err(StateError::AlreadyInState); statement to be removed from state.push

What alternative(s) have you considered?

• I am currently adding a GameState::Buffer between each GameState::Menu to work around the issue, as described above
• If duplicate states are not supposed to be allowed in the stack, then state.push should check the entire stack to make sure that there are no duplicates. Then, I could run the logic that I have in on_enter and on_exit manually instead, or use events.

[alice-i-cecile]

@maniwani, this came up in #4391 :) Like we discussed there, this behavior should be changed.

[alice-i-cecile]

The state stack has been removed by #7267.