Repetition of code

[yikaifeng]

First, i tried to make base class for screens like this:

#===============================================================================
class BaseScreen(Screen):
    
    BINDINGS = [
        ("m", "toggle_menu", "Toggle menu"),
        ("l", "toggle_log", "Toggle log"),
    ]
    
    SCREEN_ID = None

    #---------------------------------------------------------------------------
    def compose(self) -> ComposeResult:
        
        yield Footer()
        
        with Horizontal(id="main_container"):

            yield LeftMenu(LEFT_MENU_OPTIONS, id="left_menu_container")
            
            with Vertical(id="right_container"):
                with Container(id="page_container"):
                    yield from self.custom_compose()
                with Container(id="log_container"):
                    yield GlobalRichLog(id="log")
                
    
    def custom_compose(self) -> ComposeResult:
        pass
    
    
    def on_mount(self) -> None:
        
        self.query_one("#main_container").can_focus = False
        self.query_one("#left_menu_container").can_focus = False
        self.query_one("#right_container").can_focus = False
        self.query_one("#page_container").can_focus = False
        self.query_one("#log_container").can_focus = False
        self.query_one("#log").can_focus = False

    
    #---------------------------------------------------------------------------
    # Actions
    #---------------------------------------------------------------------------
    def action_toggle_menu(self) -> None:
        self.query_one("#left_menu_container", LeftMenu).toggle_class("-hidden")
        logger.info(f"'m' pressed")
        self.query_one("#log", GlobalRichLog).refresh_logs()
        
    
    def action_toggle_log(self) -> None:
        self.query_one("#log_container", Container).toggle_class("-hidden")
        logger.info(f"'l' pressed")
        self.query_one("#log", GlobalRichLog).refresh_logs()

    
    #---------------------------------------------------------------------------
    # Events
    #---------------------------------------------------------------------------
    @on(ScreenResume)
    def on_screen_resume(self, event: ScreenResume):
        logger.info(f"Screen '{self.SCREEN_ID}' resumed")
        self.query_one("#log", GlobalRichLog).refresh_logs()
        
        
#===============================================================================
if __name__ == "__main__":
    pass

The, i created some child screens. When i run app and push the first screen, everything works fine. But when i switche two the second screen, everything is duplicated: when i press l, m, in logs i see 2 messages, instead 1. When screen was switched, i also got 2 log messages. In on_mount I log messages, they also duplicated. When i switch to the thied screen, now i see 3 copies of each log message.

I thought, maybe propblem is because all child screen catches events, so I moved code to main app file:

class Manager(App):
    

    CSS_PATH = "manager.tcss"
    
    BINDINGS = [
        ("m", "toggle_menu", "Toggle menu"),
        ("l", "toggle_log", "Toggle log"),
    ]
    
    SCREENS = {
        "dash": ScreenDash,
        "ssh": ScreenSsh,
        "users_and_groups": ScreenUsersAndGroups,
    }
    

    def compose(self) -> ComposeResult:
        """Create child widgets for the app."""
        yield Label("Start screen")
        yield Footer()
        
        
    def on_mount(self):
        self.theme = "textual-dark"
        self.push_screen("dash")
        
        
    #---------------------------------------------------------------------------
    # Actions
    #---------------------------------------------------------------------------
    def action_toggle_menu(self) -> None:
        """
        Toggle menu
        """
        self.screen.query_one("#left_menu_container", LeftMenu).toggle_class("-hidden")
        logger.info(f"'m' pressed")
        self.screen.query_one("#log", GlobalRichLog).refresh_logs()
        
    
    def action_toggle_log(self) -> None:
        """
        Toggle log
        """
        self.screen.query_one("#log_container", Container).toggle_class("-hidden")
        logger.info(f"'l' pressed")
        self.screen.query_one("#log", GlobalRichLog).refresh_logs()
        
    
    #---------------------------------------------------------------------------
    # Events
    #---------------------------------------------------------------------------
    @on(ScreenResume)
    def on_screen_resume(self, event: ScreenResume):
        logger.info(f"Screen '{self.screen.SCREEN_ID}' resumed")
        self.query_one("#log", GlobalRichLog).refresh_logs()
        
    
    @on(OptionList.OptionSelected)
    def on_option_selected(self, opt: OptionList.OptionSelected) -> None:
        
        if opt.option_id=="exit":
            self.exit()
        
        else:
            self.switch_screen(opt.option_id)
        
    
    @on(Button.Pressed, "#exit")
    def on_button_exit(self) -> None:
        self.exit()

But the problem is the same. Everything from on_mount, actions and events repeats as many times, as many screen was created.

PS: i store logs in global variable, custom function refresh_logs clear all content of RichLog and load content from global variable. I tested that part of code (custom handler, which add new log messages to global variable) outside textual, there is no duplication.

---

I located the problem. Here is the modifed code of custom handler for debugging.

class GlobalLogHandler(logging.Handler):
    
    COUNT = 0
    
    def __init__(self, level=logging.NOTSET, globallog: GlobalLog = None):

        super().__init__(level)
        if globallog is None:
            raise ValueError("'globallog' argument can't be None")
        self._globallog = globallog
        
    
    def emit(self, record):
        
        try:
            self.COUNT += 1
            msg = self.format(record)
            self._globallog.append(msg + f" COUNT[{self.COUNT}] " + "\n")
            
        except RecursionError:
            raise
        
        except Exception:
            self.handleError(record)

I got result:
[2025-06-30 15:43:46] INFO | Screen 'dash' COUNT [36]
[2025-06-30 15:43:46] INFO | Screen 'dash' COUNT [35]
[2025-06-30 15:43:46] INFO | Screen 'dash' COUNT [30]

So, something calls emit several times. Directly modifying _globallog right before and after log.info(...) in code doesn't cause repetition

[yikaifeng]

I found the problem. I creted handler inside child MyLog(RichLog).init, so each instance of screen creted new handler