Support whole document operations on scalar documents (#213)

jsonpatch.py

@@ -250,6 +250,9 @@ class RemoveOperation(PatchOperation):
     def apply(self, obj):
         subobj, part = _to_last(self.pointer, obj)
 
+        if part is None:
+            raise JsonPatchConflict("can't remove the whole document")
+
         if isinstance(subobj, Sequence) and not isinstance(part, int):
             raise JsonPointerException("invalid array index '{0}'".format(part))
 
@@ -279,11 +282,11 @@ def apply(self, obj):
     def _add(self, obj, value):
         subobj, part = _to_last(self.pointer, obj)
 
-        if isinstance(subobj, MutableSequence):
-            if part is None:
-                return value  # we're replacing the root
+        if part is None:
+            return value  # we're replacing the root, whatever its type
 
-            elif part == '-':
+        if isinstance(subobj, MutableSequence):
+            if part == '-':
                 subobj.append(value)  # pylint: disable=E1103
 
             elif part > len(subobj) or part < 0:
@@ -293,16 +296,10 @@ def _add(self, obj, value):
                 subobj.insert(part, value)  # pylint: disable=E1103
 
         elif isinstance(subobj, MutableMapping):
-            if part is None:
-                obj = value  # we're replacing the root
-            else:
-                subobj[part] = value
+            subobj[part] = value
 
         else:
-            if part is None:
-                raise TypeError("invalid document type {0}".format(type(subobj)))
-            else:
-                raise JsonPatchConflict("unable to fully resolve json pointer {0}, part {1}".format(self.location, part))
+            raise JsonPatchConflict("unable to fully resolve json pointer {0}, part {1}".format(self.location, part))
         return obj
 
 
@@ -338,10 +335,7 @@ def apply(self, obj):
                 msg = "can't replace a non-existent object '{0}'".format(part)
                 raise JsonPatchConflict(msg)
         else:
-            if part is None:
-                raise TypeError("invalid document type {0}".format(type(subobj)))
-            else:
-                raise JsonPatchConflict("unable to fully resolve json pointer {0}, part {1}".format(self.location, part))
+            raise JsonPatchConflict("unable to fully resolve json pointer {0}, part {1}".format(self.location, part))
 
         subobj[part] = value
         return obj

property_tests.py

@@ -332,11 +332,10 @@ def test_does_not_modify_patch(self, case):
         outcome(jsonpatch.apply_patch, doc, patch)
         assert_json_equal(patch, saved)
 
-    @unittest.expectedFailure
     @given(docs_with_patches())
     # 'move' from the whole document crashed for array roots, #214
     @example(case=([], [{'op': 'move', 'from': '', 'path': '/-'}]))
-    # operations on the whole document crash if it is a scalar
+    # operations on the whole document crashed if it was a scalar, #213
     @example(case=(None, [{'op': 'remove', 'path': ''}]))
     def test_raises_only_documented_exceptions(self, case):
         doc, patch = case
@@ -382,9 +381,8 @@ def test_patch_as_string_gives_same_result(self, case):
 
 class OperationProperties(unittest.TestCase):
 
-    @unittest.expectedFailure
     @given(whole_document_operations())
-    # 'add' crashes if the document is a scalar, unlike 'replace'
+    # 'add' crashed if the document was a scalar, unlike 'replace', #213
     @example(case=(None, {'op': 'add', 'path': '', 'value': 0}, 0))
     def test_whole_document_as_target(self, case):
         doc, operation, expected = case

tests.py

@@ -166,6 +166,35 @@ def test_add_whole_document_list_root_raises_no_bare_typeerror(self):
         except TypeError:
             self.fail("root add on an array root raised a bare TypeError")
 
+    def test_whole_document_scalar_root(self):
+        # a JSON document can also be a scalar (#213); operations on the whole
+        # document have to work on it as on an object or array root
+        for obj in (None, True, 5, 1.5, 'foo'):
+            with self.subTest(obj=obj):
+                for op in ('add', 'replace'):
+                    res = jsonpatch.apply_patch(
+                        obj, [{'op': op, 'path': '', 'value': {'baz': 'qux'}}])
+                    self.assertEqual(res, {'baz': 'qux'})
+                for op in ('copy', 'move'):
+                    res = jsonpatch.apply_patch(
+                        obj, [{'op': op, 'from': '', 'path': ''}])
+                    self.assertEqual(res, obj)
+
+    def test_remove_whole_document(self):
+        # there would be no document left, whatever the type of the root
+        for obj in (None, True, 5, 1.5, 'foo', {'foo': 'bar'}, ['foo']):
+            with self.subTest(obj=obj):
+                self.assertRaises(jsonpatch.JsonPatchConflict,
+                                  jsonpatch.apply_patch,
+                                  obj, [{'op': 'remove', 'path': ''}])
+
+    def test_move_whole_document_scalar_root_into_child(self):
+        for obj in (None, 5, 'foo'):
+            with self.subTest(obj=obj):
+                self.assertRaises(jsonpatch.JsonPatchConflict,
+                                  jsonpatch.apply_patch,
+                                  obj, [{'op': 'move', 'from': '', 'path': '/foo'}])
+
     def test_replace_array_item(self):
         obj = {'foo': ['bar', 'qux', 'baz']}
         res = jsonpatch.apply_patch(obj, [{'op': 'replace', 'path': '/foo/1',