Merge pull request matplotlib#25710 from ksunden/bbox_intersect_return_type

TYP: Fix type hint (and docstring) for Bbox.intersection

Author: tacaswell

lib/matplotlib/artist.py

@@ -361,16 +361,17 @@ def get_tightbbox(self, renderer=None):
 
         Returns
         -------
-        `.Bbox`
+        `.Bbox` or None
             The enclosing bounding box (in figure pixel coordinates).
+            Returns None if clipping results in no intersection.
         """
         bbox = self.get_window_extent(renderer)
         if self.get_clip_on():
             clip_box = self.get_clip_box()
             if clip_box is not None:
                 bbox = Bbox.intersection(bbox, clip_box)
             clip_path = self.get_clip_path()
-            if clip_path is not None:
+            if clip_path is not None and bbox is not None:
                 clip_path = clip_path.get_fully_transformed_path()
                 bbox = Bbox.intersection(bbox, clip_path.get_extents())
         return bbox

lib/matplotlib/transforms.pyi

@@ -105,7 +105,7 @@ class BboxBase(TransformNode):
     @staticmethod
     def union(bboxes: Sequence[BboxBase]) -> Bbox: ...
     @staticmethod
-    def intersection(bbox1: BboxBase, bbox2: BboxBase) -> Bbox: ...
+    def intersection(bbox1: BboxBase, bbox2: BboxBase) -> Bbox | None: ...
 
 class Bbox(BboxBase):
     def __init__(self, points: ArrayLike, **kwargs) -> None: ...