fix: escape the key with ~ or/in its the json Pointer name

Author: lingbohome

Src/JsonDiffPatchDotNet.UnitTests/JsonDeltaFormatterUnitTests.cs

@@ -1,6 +1,7 @@
 using JsonDiffPatchDotNet.Formatters.JsonPatch;
 using Newtonsoft.Json.Linq;
 using NUnit.Framework;
+using System.Linq;
 
 namespace JsonDiffPatchDotNet.UnitTests
 {
@@ -121,6 +122,20 @@ public void Format_ArrayRemoveInDescOrder_Success()
 			AssertOperation(operations[1], OperationTypes.Remove, "/1");
 		}
 
+		[Test]
+		public void Format_EscapeOfJsonPointer_Success()
+		{
+			var left = JObject.Parse(@"{ ""a/b"": ""a"", ""a~b"": ""ab"", ""a/~b"": ""abb"",""a/b/c~"": ""abc"" }");
+			var right = JObject.Parse(@"{ ""a/b"": ""ab"", ""a~b"": ""ba"", ""a/~b"": ""bba"",""a/b/c~"": ""cba""  }");
+			var patch = Differ.Diff(left, right);
+			var operations = Formatter.Format(patch);
+
+			Assert.IsTrue(operations.Any(x => x.Path.Equals("/a~1b") && x.Value.ToString().Equals("ab")));
+			Assert.IsTrue(operations.Any(x => x.Path.Equals("/a~0b") && x.Value.ToString().Equals("ba")));
+			Assert.IsTrue(operations.Any(x => x.Path.Equals("/a~1~0b") && x.Value.ToString().Equals("bba")));
+			Assert.IsTrue(operations.Any(x => x.Path.Equals("/a~1b~1c~0") && x.Value.ToString().Equals("cba")));
+		}
+
 		private void AssertOperation(Operation operation, string expectedOp, string expectedPath, JValue expectedValue = null)
 		{
 			Assert.AreEqual(expectedOp, operation.Op);

Src/JsonDiffPatchDotNet/Formatters/JsonPatch/JsonDeltaFormatter.cs

@@ -51,7 +51,7 @@ protected override void Format(DeltaType type, JsonFormatContext context, JToken
 
 		protected override void NodeBegin(JsonFormatContext context, string key, string leftKey, DeltaType type, NodeType nodeType, bool isLast)
 		{
-			context.Path.Add(leftKey);
+			context.Path.Add(Escape(leftKey));
 		}
 
 		protected override void NodeEnd(JsonFormatContext context, string key, string leftKey, DeltaType type, NodeType nodeType, bool isLast)
@@ -64,6 +64,13 @@ protected override void RootBegin(JsonFormatContext context, DeltaType type, Nod
 
 		protected override void RootEnd(JsonFormatContext context, DeltaType type, NodeType nodeType) { }
 
+		private string Escape(string key)
+		{
+			if (string.IsNullOrEmpty(key)) return key;
+			return key.Replace("~", "~0")
+				.Replace("/", "~1");
+		}
+
 		private void FormatNode(JsonFormatContext context, JToken delta, JToken left)
 		{
 			FormatDeltaChildren(context, delta, left);