From 7a8d6920e81a819e44ee3a8d7bba83ba35140e02 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rodrigo=20Gir=C3=A3o=20Serr=C3=A3o?=
 <5621605+rodrigogiraoserrao@users.noreply.github.com>
Date: Tue, 16 May 2023 11:14:54 +0100
Subject: [PATCH 1/2] Error when dismissing non-active screen.

Related issues: #2575.
---
 CHANGELOG.md          |  1 +
 src/textual/app.py    |  2 +-
 src/textual/screen.py |  9 +++++++++
 tests/test_screens.py | 14 ++++++++++++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5991f818d..bce29efda 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - App `title` and `sub_title` attributes can be set to any type https://github.com/Textualize/textual/issues/2521
 - Using `Widget.move_child` where the target and the child being moved are the same is now a no-op https://github.com/Textualize/textual/issues/1743
+- Calling `dismiss` on a screen that is not at the top of the stack now raises an exception https://github.com/Textualize/textual/issues/2575
 
 ### Fixed
 
diff --git a/src/textual/app.py b/src/textual/app.py
index 12f66cf04..c1376cd22 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -156,7 +156,7 @@ class ScreenError(Exception):
 
 
 class ScreenStackError(ScreenError):
-    """Raised when attempting to pop the last screen from the stack."""
+    """Raised when trying to manipulate the screen stack incorrectly."""
 
 
 class CssPathError(Exception):
diff --git a/src/textual/screen.py b/src/textual/screen.py
index af0b006be..a16273121 100644
--- a/src/textual/screen.py
+++ b/src/textual/screen.py
@@ -28,6 +28,7 @@ from ._callback import invoke
 from ._compositor import Compositor, MapGeometry
 from ._context import visible_screen_stack
 from ._types import CallbackType
+from .app import ScreenStackError
 from .binding import Binding
 from .css.match import match
 from .css.parse import parse_selectors
@@ -771,6 +772,10 @@ class Screen(Generic[ScreenResultType], Widget):
         Args:
             result: The optional result to be passed to the result callback.
 
+        Raises:
+            ScreenStackError: If trying to dismiss a screen that is not at the top of
+                the stack.
+
         Note:
             If the screen was pushed with a callback, the callback will be
             called with the given result and then a call to
@@ -778,6 +783,10 @@ class Screen(Generic[ScreenResultType], Widget):
             no callback was provided calling this method is the same as
             simply calling [`App.pop_screen`][textual.app.App.pop_screen].
         """
+        if self is not self.app.screen:
+            raise ScreenStackError(
+                f"Can't dismiss screen {self} that's not at the top of the stack."
+            )
         if result is not self._NoResult and self._result_callbacks:
             self._result_callbacks[-1](cast(ScreenResultType, result))
         self.app.pop_screen()
diff --git a/tests/test_screens.py b/tests/test_screens.py
index 2e3dbfcbe..5b29b1dd5 100644
--- a/tests/test_screens.py
+++ b/tests/test_screens.py
@@ -192,3 +192,17 @@ async def test_auto_focus():
         assert app.focused is None
         app.pop_screen()
         assert app.focused.id == "two"
+
+
+async def test_dismiss_non_top_screen():
+    class MyApp(App[None]):
+        async def key_p(self) -> None:
+            self.bottom, top = Screen(), Screen()
+            await self.push_screen(self.bottom)
+            await self.push_screen(top)
+
+    app = MyApp()
+    async with app.run_test() as pilot:
+        await pilot.press("p")
+        with pytest.raises(ScreenStackError):
+            app.bottom.dismiss()

From 93f4de918ce5dfa9f29ea693a2f815282def6625 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rodrigo=20Gir=C3=A3o=20Serr=C3=A3o?=
 <5621605+rodrigogiraoserrao@users.noreply.github.com>
Date: Tue, 16 May 2023 11:30:14 +0100
Subject: [PATCH 2/2] Fix circular import.

---
 src/textual/screen.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/textual/screen.py b/src/textual/screen.py
index a16273121..09505cc53 100644
--- a/src/textual/screen.py
+++ b/src/textual/screen.py
@@ -28,7 +28,6 @@ from ._callback import invoke
 from ._compositor import Compositor, MapGeometry
 from ._context import visible_screen_stack
 from ._types import CallbackType
-from .app import ScreenStackError
 from .binding import Binding
 from .css.match import match
 from .css.parse import parse_selectors
@@ -784,6 +783,8 @@ class Screen(Generic[ScreenResultType], Widget):
             simply calling [`App.pop_screen`][textual.app.App.pop_screen].
         """
         if self is not self.app.screen:
+            from .app import ScreenStackError
+
             raise ScreenStackError(
                 f"Can't dismiss screen {self} that's not at the top of the stack."
             )