fix(animation): LaggedStartMap Restore builds subanimations

manim/animation/composition.py

@@ -413,9 +413,26 @@ def identity(mob: Mobject) -> Mobject:
 
             arg_creator = identity
 
+        def animation_args(value: Any) -> tuple[Any, ...]:
+            # ``arg_creator`` may return either a tuple of constructor args (e.g.
+            # ``(m.set_color, YELLOW)``) or a single mobject (the default identity).
+            # Only tuples are unpacked; mobjects must be passed as a single argument
+            # so animations like ``Restore(mob)`` are not called as ``Restore(*mob)``.
+            if isinstance(value, tuple):
+                return value
+            return (value,)
+
         args_list = [arg_creator(submob) for submob in mobject]
+        if not args_list:
+            raise ValueError(
+                f"LaggedStartMap cannot build animations from {mobject!r}: "
+                "it has no submobjects to map over. Pass a VGroup of the "
+                "targets to animate, or provide a non-empty mobject."
+            )
         anim_kwargs = dict(kwargs)
         if "lag_ratio" in anim_kwargs:
             anim_kwargs.pop("lag_ratio")
-        animations = [animation_class(*args, **anim_kwargs) for args in args_list]
+        animations = [
+            animation_class(*animation_args(args), **anim_kwargs) for args in args_list
+        ]
         super().__init__(*animations, run_time=run_time, lag_ratio=lag_ratio)

tests/module/animation/test_composition.py

@@ -8,6 +8,7 @@
 from manim.animation.composition import AnimationGroup, LaggedStartMap, Succession
 from manim.animation.creation import Create, Write
 from manim.animation.fading import FadeIn, FadeOut
+from manim.animation.transform import Restore
 from manim.constants import DOWN, UP
 from manim.mobject.geometry.arc import Circle
 from manim.mobject.geometry.line import Line
@@ -191,6 +192,24 @@ def finish(self):
     assert circ_animation.finished
 
 
+def test_laggedstartmap_restore_builds_subanimations():
+    mobject = VGroup(Square(), Square().shift(UP))
+    for submob in mobject:
+        submob.save_state()
+        submob.scale(0)
+    animation = LaggedStartMap(Restore, mobject, lag_ratio=0.1, run_time=1)
+    assert len(animation.animations) == len(mobject)
+    assert all(
+        isinstance(subanimation, Restore) for subanimation in animation.animations
+    )
+
+
+def test_laggedstartmap_empty_mobject_raises():
+    mobject = VGroup()
+    with pytest.raises(ValueError, match="no submobjects"):
+        LaggedStartMap(Restore, mobject)
+
+
 def test_laggedstartmap_only_passes_kwargs_to_subanimations():
     mobject = VGroup(Square(), Circle())
     animation = LaggedStartMap(