Improved implementation of Path.copy and deepcopy

The original Path.copy raised RecursionError, new implementation mimicks
deepcopy, creating shared members.

Path tests were updated to utilize member functions copy and deepcopy
instead of builtin copy functional protocol.

Author: deep-jkl

lib/matplotlib/path.py

@@ -264,8 +264,13 @@ def __copy__(self):
         Return a shallow copy of the `Path`, which will share the
         vertices and codes with the source `Path`.
         """
-        import copy
-        return copy.copy(self)
+        try:
+            codes = self.codes
+        except AttributeError:
+            codes = None
+        return self.__class__(
+            self.vertices, codes,
+            _interpolation_steps=self._interpolation_steps)
 
     copy = __copy__
 

lib/matplotlib/tests/test_path.py

@@ -1,4 +1,3 @@
-import copy
 import re
 
 import numpy as np
@@ -333,8 +332,28 @@ def test_path_deepcopy():
     codes = [Path.MOVETO, Path.LINETO]
     path1 = Path(verts)
     path2 = Path(verts, codes)
-    copy.deepcopy(path1)
-    copy.deepcopy(path2)
+    path1_copy = path1.deepcopy()
+    path2_copy = path2.deepcopy()
+    assert(path1 is not path1_copy)
+    assert(path1.vertices is not path1_copy.vertices)
+    assert(path2 is not path2_copy)
+    assert(path2.vertices is not path2_copy.vertices)
+    assert(path2.codes is not path2_copy.codes)
+
+
+def test_path_shallowcopy():
+    # Should not raise any error
+    verts = [[0, 0], [1, 1]]
+    codes = [Path.MOVETO, Path.LINETO]
+    path1 = Path(verts)
+    path2 = Path(verts, codes)
+    path1_copy = path1.copy()
+    path2_copy = path2.copy()
+    assert(path1 is not path1_copy)
+    assert(path1.vertices is path1_copy.vertices)
+    assert(path2 is not path2_copy)
+    assert(path2.vertices is path2_copy.vertices)
+    assert(path2.codes is path2_copy.codes)
 
 
 @pytest.mark.parametrize('phi', np.concatenate([