Merge pull request #28490 from meeseeksmachine/auto-backport-of-pr-28…

…486-on-v3.9.x

Backport PR #28486 on branch v3.9.x (Fix CompositeGenericTransform.contains_branch_seperately)

lib/matplotlib/tests/test_transforms.py

@@ -667,6 +667,13 @@ def test_contains_branch(self):
 
         assert not self.stack1.contains_branch(self.tn1 + self.ta2)
 
+        blend = mtransforms.BlendedGenericTransform(self.tn2, self.stack2)
+        x, y = blend.contains_branch_seperately(self.stack2_subset)
+        stack_blend = self.tn3 + blend
+        sx, sy = stack_blend.contains_branch_seperately(self.stack2_subset)
+        assert x is sx is False
+        assert y is sy is True
+
     def test_affine_simplification(self):
         # tests that a transform stack only calls as much is absolutely
         # necessary "non-affine" allowing the best possible optimization with

lib/matplotlib/transforms.py

@@ -1423,7 +1423,7 @@ def contains_branch_seperately(self, other_transform):
                              'transforms with 2 output dimensions')
         # for a non-blended transform each separate dimension is the same, so
         # just return the appropriate shape.
-        return [self.contains_branch(other_transform)] * 2
+        return (self.contains_branch(other_transform), ) * 2
 
     def __sub__(self, other):
         """
@@ -2404,6 +2404,15 @@ def _iter_break_from_left_to_right(self):
         for left, right in self._b._iter_break_from_left_to_right():
             yield self._a + left, right
 
+    def contains_branch_seperately(self, other_transform):
+        # docstring inherited
+        if self.output_dims != 2:
+            raise ValueError('contains_branch_seperately only supports '
+                             'transforms with 2 output dimensions')
+        if self == other_transform:
+            return (True, True)
+        return self._b.contains_branch_seperately(other_transform)
+
     depth = property(lambda self: self._a.depth + self._b.depth)
     is_affine = property(lambda self: self._a.is_affine and self._b.is_affine)
     is_separable = property(