Routing / Navigation broken since flet 0.28.2

[NiTRoeSE]

Duplicate Check

• I have searched the opened issues and there are no duplicates

Describe the bug

Working navigation like inplemented like in this example:
https://flet.dev/docs/getting-started/navigation-and-routing/#building-views-on-route-change
seems broken or something changed and is undocumented ?

If you use the example and navigate back through the buttons (not the back arrows) it throws following error:

Future exception was never retrieved
future: <Future finished exception=IndexError('list index out of range')>
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/python@3.13/3.13.2/Frameworks/Python.framework/Versions/3.13/lib/python3.13/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/nitro/flet_build/scriptrunner_flet/venv/lib/python3.13/site-packages/flet/core/page.py", line 906, in wrapper
    handler(*args)
    ~~~~~~~^^^^^^^
  File "/Users/nitro/flet_build/scriptrunner_flet/test.py", line 31, in view_pop
    top_view = page.views[-1]
               ~~~~~~~~~~^^^^
IndexError: list index out of range

So something goes wrong with page.on_view_pop = view_pop

Same app or navigation build like in example works fine in flet < 0.28.2.

Code sample

Code

import flet as ft

def main(page: ft.Page):
    page.title = "Routes Example"

    def route_change(route):
        page.views.clear()
        page.views.append(
            ft.View(
                "/",
                [
                    ft.AppBar(title=ft.Text("Flet app"), bgcolor=ft.Colors.SURFACE_CONTAINER_HIGHEST),
                    ft.ElevatedButton("Visit Store", on_click=lambda _: page.go("/store")),
                ],
            )
        )
        if page.route == "/store":
            page.views.append(
                ft.View(
                    "/store",
                    [
                        ft.AppBar(title=ft.Text("Store"), bgcolor=ft.Colors.SURFACE_CONTAINER_HIGHEST),
                        ft.ElevatedButton("Go Home", on_click=lambda _: page.go("/")),
                    ],
                )
            )
        page.update()

    def view_pop(view):
        page.views.pop()
        top_view = page.views[-1]
        page.go(top_view.route)

    page.on_route_change = route_change
    page.on_view_pop = view_pop
    page.go(page.route)


ft.app(main)

To reproduce

Use example and run with flet 0.28.2

Expected behavior

That it works like in previous versions.

Screenshots / Videos

Captures

Operating System

macOS

Operating system details

15.4.1

Flet version

0.28.2

Regression

Yes, it used to work in a previous Flet version (please specify the version in additional details)

Suggestions

i dont know...

Logs

Logs

(venv)  nitro@Mac  ~/flet_build/scriptrunner_flet   main ±  python test.py
Future exception was never retrieved
future: <Future finished exception=IndexError('list index out of range')>
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/python@3.13/3.13.2/Frameworks/Python.framework/Versions/3.13/lib/python3.13/concurrent/futures/thread.py", line 59, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/Users/nitro/flet_build/scriptrunner_flet/venv/lib/python3.13/site-packages/flet/core/page.py", line 906, in wrapper
    handler(*args)
    ~~~~~~~^^^^^^^
  File "/Users/nitro/flet_build/scriptrunner_flet/test.py", line 31, in view_pop
    top_view = page.views[-1]
               ~~~~~~~~~~^^^^
IndexError: list index out of range

Additional details

No response

[FeodorFitsner]

Sorry, but how would someone "navigate back through the buttons"? It works fine with the mouse:

Screen.Recording.2025-05-13.at.2.12.35.PM.mov

[C69Xg3sg9PAvYK]

I have the same issue.

[FeodorFitsner]

Looking into that.

[NiTRoeSE]

Sorry, but how would someone "navigate back through the buttons"? It works fine with the mouse:
Screen.Recording.2025-05-13.at.2.12.35.PM.mov

Yes i mean using the mouse but clicking with it on the buttons " Visit Store" and "Go Home".
If you click "Visit Store" and want to go back with the "Go Home" Button instead of using the Arrow button in appbar to go back then the error is shown.

Or in other words if you use on_click=lambda _: page.go("/") on a button to navigate back the error is thrown.

[FeodorFitsner]

Got it. Can reproduce. Looking into that.

[Ayyouayy]

This is used

 def view_pop(view):
        page.views.pop()
        if page.views: 
            top_view = page.views[-1]
            page.go(top_view.route)

[FeodorFitsner]

We've made a fix coming in 0.28.3, so won't need to change the logic.

[puppylionmonkey]

我是會觸發pop之後無限遞迴下去，直接把所有page.view刪光光