From 52ac87ac29bd797d7d4372997e6df23b0509d039 Mon Sep 17 00:00:00 2001
From: Will McGugan <willmcgugan@gmail.com>
Date: Thu, 30 May 2024 16:25:50 +0100
Subject: [PATCH] restore sanity check

---
 src/textual/app.py    | 5 +++--
 src/textual/timer.py  | 7 ++++++-
 src/textual/widget.py | 1 -
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/textual/app.py b/src/textual/app.py
index a19d71b588..4cda806968 100644
--- a/src/textual/app.py
+++ b/src/textual/app.py
@@ -3362,10 +3362,11 @@ async def _prune_nodes(self, widgets: list[Widget]) -> None:
         Args:
             widgets: Widgets to remove.
         """
+        if not self.is_attached:
+            return
         async with self._dom_lock:
             for widget in widgets:
-                if self.is_attached:
-                    await self._prune_node(widget)
+                await self._prune_node(widget)
 
     async def _prune_node(self, root: Widget) -> None:
         """Remove a node and its children. Children are removed before parents.
diff --git a/src/textual/timer.py b/src/textual/timer.py
index 0dffc7fc9a..3845e0183c 100644
--- a/src/textual/timer.py
+++ b/src/textual/timer.py
@@ -104,7 +104,12 @@ async def _stop_all(cls, timers: Iterable[Timer]) -> None:
             timers: A number of timers.
         """
 
-        async def stop_timer(timer) -> None:
+        async def stop_timer(timer: Timer) -> None:
+            """Stop a timer and wait for it to finish.
+
+            Args:
+                timer: A Timer instance.
+            """
             if timer._task is not None:
                 timer._active.set()
                 timer._task.cancel()
diff --git a/src/textual/widget.py b/src/textual/widget.py
index e7e87ecbf4..459a64e5c4 100644
--- a/src/textual/widget.py
+++ b/src/textual/widget.py
@@ -935,7 +935,6 @@ def mount(
             provided a ``MountError`` will be raised.
         """
         if not self.is_attached:
-            return AwaitMount(self, [])
             raise MountError(f"Can't mount widget(s) before {self!r} is mounted")
         # Check for duplicate IDs in the incoming widgets
         ids_to_mount = [widget.id for widget in widgets if widget.id is not None]