Merge pull request #6412 from Textualize/on-complete-fix

fix on complete

Author: willmcgugan

.gitignore

@@ -8,6 +8,8 @@ docs/build
 docs/source/_build
 tools/*.txt
 playground/
+.mypy_cache/
+.screenshot_cache/
 
 # Byte-compiled / optimized / DLL files
 __pycache__/
@@ -129,3 +131,6 @@ sandbox/
 
 # Used by mkdocs-material social plugin
 .cache
+
+# Snapshot tests output
+__snapshots__/

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [8.1.1] - 2026-03-10
+
+### Fixed
+
+- Hotfix for animation on complete https://github.com/Textualize/textual/pull/6412
+
 ## [8.1.0] - 2026-03-10
 
 ### Changed
@@ -3381,6 +3387,7 @@ https://textual.textualize.io/blog/2022/11/08/version-040/#version-040
 - New handler system for messages that doesn't require inheritance
 - Improved traceback handling
 
+[8.1.1]: https://github.com/Textualize/textual/compare/v8.1.0...v8.1.1
 [8.1.0]: https://github.com/Textualize/textual/compare/v8.0.2...v8.1.0
 [8.0.2]: https://github.com/Textualize/textual/compare/v8.0.1...v8.0.2
 [8.0.1]: https://github.com/Textualize/textual/compare/v8.0.0...v8.0.1

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "textual"
-version = "8.1.0"
+version = "8.1.1"
 homepage = "https://github.com/Textualize/textual"
 repository = "https://github.com/Textualize/textual"
 documentation = "https://textual.textualize.io/"
@@ -36,6 +36,7 @@ include = [
     # that works around that.
     { path = "docs-offline/**/*", format = "sdist" },
 ]
+exclude = ["tests/snapshot_tests/__snapshots__"]
 
 [tool.poetry.urls]
 "Bug Tracker" = "https://github.com/Textualize/textual/issues"

src/textual/_animator.py

@@ -458,10 +458,7 @@ def _animate(
 
         if (current_animation := self._animations.get(animation_key)) is not None:
             if (on_complete := current_animation.on_complete) is not None:
-                on_complete()
-                self._animations.pop(animation_key)
-            if current_animation == animation:
-                return
+                self.app.call_later(on_complete)
 
         self._animations[animation_key] = animation
         self._timer.resume()

tests/test_animation.py

@@ -213,34 +213,89 @@ async def test_cancel_widget_non_animation() -> None:
         assert not pilot.app.animator.is_being_animated(widget, "counter")
 
 
-async def test_double_animation_on_complete() -> None:
-    """Test that animating an attribute a second time, fires its `on_complete` callback."""
+async def test_double_animation_same_value_on_complete() -> None:
+    """Test that animating an attribute a second time to the same value, fires its `on_complete` callback."""
 
-    complete_count = 0
+    completed: list[str] = []
 
     class AnimApp(App):
         x = var(0)
 
-        def on_key(self) -> None:
+        async def animate_a(self) -> None:
 
             def on_complete() -> None:
-                nonlocal complete_count
-                complete_count += 1
+                completed.append("a")
 
             self.animator.animate(
                 self,
                 "x",
-                100 + complete_count,
+                100,
+                duration=0.1,
+                on_complete=on_complete,
+            )
+
+        async def animate_b(self) -> None:
+
+            def on_complete() -> None:
+                completed.append("b")
+
+            self.animator.animate(
+                self,
+                "x",
+                100,
+                duration=0.1,
+                on_complete=on_complete,
+            )
+
+    app = AnimApp()
+    async with app.run_test() as pilot:
+        await app.animate_a()
+        assert app.x != 100
+        await app.animate_b()
+        await pilot.wait_for_animation()
+        assert completed == ["a", "b"]
+        assert app.x == 100
+
+
+async def test_double_animation_different_value_on_complete() -> None:
+    """Test that animating an attribute a second time to a different value, fires its `on_complete` callback."""
+
+    completed: list[str] = []
+
+    class AnimApp(App):
+        x = var(0)
+
+        async def animate_a(self) -> None:
+
+            def on_complete() -> None:
+                completed.append("a")
+
+            self.animator.animate(
+                self,
+                "x",
+                100,
+                duration=0.1,
+                on_complete=on_complete,
+            )
+
+        async def animate_b(self) -> None:
+
+            def on_complete() -> None:
+                completed.append("b")
+
+            self.animator.animate(
+                self,
+                "x",
+                101,
                 duration=0.1,
                 on_complete=on_complete,
             )
 
     app = AnimApp()
     async with app.run_test() as pilot:
-        # Press space twice to initiate 2 animations
-        await pilot.press("space")
-        await pilot.press("space")
-        # Wait for animations to complete
+        await app.animate_a()
+        assert app.x != 101
+        await app.animate_b()  # animate to different value
         await pilot.wait_for_animation()
-        # Check that on_complete callback was invoked twice
-        assert complete_count == 2
+        assert completed == ["a", "b"]
+        assert app.x == 101