Raise ValueError for non-finite distance to buffer/offset_curve (#1522)

shapely/geometry/base.py

@@ -464,6 +464,8 @@ def buffer(
 
         if mitre_limit == 0.0:
             raise ValueError("Cannot compute offset from zero-length line segment")
+        elif not np.isfinite(distance):
+            raise ValueError("buffer distance must be finite")
 
         return shapely.buffer(
             self,

shapely/geometry/linestring.py

@@ -1,5 +1,6 @@
 """Line strings and related utilities
 """
+import numpy as np
 
 import shapely
 from shapely.geometry.base import BaseGeometry, JOIN_STYLE
@@ -146,6 +147,8 @@ def offset_curve(
         """
         if mitre_limit == 0.0:
             raise ValueError("Cannot compute offset from zero-length line segment")
+        elif not np.isfinite(distance):
+            raise ValueError("offset_curve distance must be finite")
         return shapely.offset_curve(self, distance, quad_segs, join_style, mitre_limit)
 
     def parallel_offset(

tests/test_buffer.py

@@ -6,6 +6,13 @@
 from shapely.constructive import BufferCapStyle, BufferJoinStyle
 
 
+@pytest.mark.parametrize("distance", [float("nan"), float("inf")])
+def test_non_finite_distance(distance):
+    g = geometry.Point(0, 0)
+    with pytest.raises(ValueError, match="distance must be finite"):
+        g.buffer(distance)
+
+
 class BufferTests(unittest.TestCase):
     """Test Buffer Point/Line/Polygon with and without single_sided params"""
 

tests/test_parallel_offset.py

@@ -1,8 +1,17 @@
+import pytest
+
 from . import unittest
 from shapely.geometry import LineString, LinearRing
 from shapely.testing import assert_geometries_equal
 
 
+@pytest.mark.parametrize("distance", [float("nan"), float("inf")])
+def test_non_finite_distance(distance):
+    g = LineString([(0, 0), (10, 0)])
+    with pytest.raises(ValueError, match="distance must be finite"):
+        g.parallel_offset(distance)
+
+
 class OperationsTestCase(unittest.TestCase):
 
     def test_parallel_offset_linestring(self):