change self to self.copy() in Line, and remove the previous change in pointwise_become_partial()

Author: irvanalhaq9

manim/mobject/geometry/line.py

@@ -133,7 +133,7 @@ def _account_for_buff(self, buff: float) -> None:
         if length < 2 * buff:
             return
         buff_proportion = buff / length
-        self.pointwise_become_partial(self, buff_proportion, 1 - buff_proportion)
+        self.pointwise_become_partial(self.copy(), buff_proportion, 1 - buff_proportion)
         return
 
     def _set_start_and_end_attrs(

manim/mobject/types/vectorized_mobject.py

@@ -1938,32 +1938,24 @@ def pointwise_become_partial(
                 upper_residue,
             )
         else:
-            # Copy points if self.points is vmobject.points before setting
-            # self.points = np.empty(...) to avoid in-place modification
-            vmobject_points = (
-                vmobject.points.copy()
-                if self.points is vmobject.points
-                else vmobject.points
-            )
-
             # Allocate space for (upper_index-lower_index+1) Bézier curves.
             self.points = np.empty((nppc * (upper_index - lower_index + 1), self.dim))
             # Look at the "lower_index"-th Bezier curve and select its part from
             # t=lower_residue to t=1. This is the first curve in self.points.
             self.points[:nppc] = partial_bezier_points(
-                vmobject_points[nppc * lower_index : nppc * (lower_index + 1)],
+                vmobject.points[nppc * lower_index : nppc * (lower_index + 1)],
                 lower_residue,
                 1,
             )
             # If there are more curves between the "lower_index"-th and the
             # "upper_index"-th Béziers, add them all to self.points.
-            self.points[nppc:-nppc] = vmobject_points[
+            self.points[nppc:-nppc] = vmobject.points[
                 nppc * (lower_index + 1) : nppc * upper_index
             ]
             # Look at the "upper_index"-th Bézier curve and select its part from
             # t=0 to t=upper_residue. This is the last curve in self.points.
             self.points[-nppc:] = partial_bezier_points(
-                vmobject_points[nppc * upper_index : nppc * (upper_index + 1)],
+                vmobject.points[nppc * upper_index : nppc * (upper_index + 1)],
                 0,
                 upper_residue,
             )