error on self pop

src/textual/app.py

@@ -2514,13 +2514,18 @@ class App(Generic[ReturnType], DOMNode):
         Returns:
             The screen that was replaced.
         """
-
+        _rich_traceback_omit = True
         screen_stack = self._screen_stack
         if len(screen_stack) <= 1:
             raise ScreenStackError(
                 "Can't pop screen; there must be at least one screen on the stack"
             )
 
+        if active_message_pump.get() is self.screen:
+            raise ScreenError(
+                f"Can't pop screen {self.screen} from it's own message loop; Consider using the @work decorator."
+            )
+
         previous_screen = screen_stack.pop()
         previous_screen._pop_result_callback()
         self.screen.post_message(events.ScreenResume())

tests/test_screens.py

@@ -7,7 +7,7 @@ import threading
 import pytest
 
 from textual import work
-from textual.app import App, ComposeResult, ScreenStackError
+from textual.app import App, ComposeResult, ScreenError, ScreenStackError
 from textual.events import MouseMove
 from textual.geometry import Offset
 from textual.screen import Screen
@@ -624,3 +624,20 @@ async def test_worker_cancellation():
         # Press enter to activate button to dismiss them
         await pilot.press("enter")
         await pilot.press("enter")
+
+
+async def test_self_pop_screen():
+    """Regression test for https://github.com/Textualize/textual/issues/5008"""
+
+    class MyScreen(Screen):
+        def on_mount(self):
+            self.app.pop_screen()
+
+    class PopApp(App):
+        def on_mount(self) -> None:
+            self.push_screen(MyScreen())
+
+    app = PopApp()
+    with pytest.raises(ScreenError):
+        async with app.run_test() as pilot:
+            pass