memory leak problem

[viethoang261]

Duplicate Check

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

Describe the bug

When using custom control, if you create an attribute to manage data or do some state management, those will not be freed up when that control is removed from the parent, so it will cause a memory leak, even using gc.collect() won't help

Code sample

Code

import flet as ft

class FirstPage(ft.Column):
    def __init__(self):
        super().__init__()
        self.alignment = ft.MainAxisAlignment.CENTER
        self.horizontal_alignment = ft.CrossAxisAlignment.CENTER
        
        size_in_mb = 100
        string_sample = "Hello, world!"  # Example string (~13 bytes)
        num_strings = (size_in_mb * 1024 * 1024) // len(string_sample)  # Calculate how many fit in 100MB
        self.string_list = [string_sample] * num_strings  # Create the list
        self.strings = ', '.join(self.string_list)
        self.strings = ', '.join(self.string_list)
        self.controls = [
            ft.Text("First Page"),
            ft.Text(f"total length: {len(self.string_list)}"),
            ft.ElevatedButton("Go to Second Page", on_click=self.go_to_second_page),
        ]
        
    def will_unmount(self):
        super().will_unmount()
        
    def go_to_second_page(self, e):
        self.page.go("/second")
        
class SecondPage(ft.Column):
    def __init__(self):
        super().__init__()
        self.alignment = ft.MainAxisAlignment.CENTER
        self.horizontal_alignment = ft.CrossAxisAlignment.CENTER
        
        size_in_mb = 100
        string_sample = "Hello, world!"  # Example string (~13 bytes)
        num_strings = (size_in_mb * 1024 * 1024) // len(string_sample)  # Calculate how many fit in 100MB
        self.string_list = [string_sample] * num_strings  # Create the list
        self.strings = ', '.join(self.string_list)
        self.controls = [
            ft.Text("Second Page"),
            ft.Text(f"total length: {len(self.string_list)}"),
            ft.ElevatedButton("Go to First Page", on_click=self.go_to_first_page),
        ]
        
    def will_unmount(self):
        super().will_unmount()
        
    def go_to_first_page(self, e):
        self.page.go("/first")
        

def main(page: ft.Page):
    page.title = "Flet memory example"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER
    page.horizontal_alignment = ft.CrossAxisAlignment.CENTER
    page.window.width = 800
    page.window.height = 600

    def route_change(_):
        if page.route == "/first":
            page.controls.clear()
            page.add(FirstPage())
        elif page.route == "/second":
            page.controls.clear()
            page.add(SecondPage())
        page.update()

    page.on_route_change = route_change
    
    page.go("/first")
    

ft.app(main)

To reproduce

...

Expected behavior

No response

Screenshots / Videos

Captures

first when starting the app

after switching pages several times

Operating System

Linux

Operating system details

ubuntu22

Flet version

latest

Regression

No, it isn't

Suggestions

I found a solution: clear all class attributes in the will_unmount event, and the memory leak is gone

after applying the code
when starting the app

after switching pages several times

Hope this small modification will help

Logs

Logs

[Paste your logs here]

Additional details

No response