Fix for issue #61 (#74)

Author: wdonne

impl/src/main/java/org/glassfish/json/JsonPatchImpl.java

@@ -289,32 +289,42 @@ private void diffArray(String path, JsonArray source, JsonArray target) {
                 }
             }
 
-            int i = m;
-            int j = n;
-            while (i > 0 || j > 0) {
-                if (i == 0) {
-                    j--;
-                    builder.add(path + '/' + j, target.get(j));
-                } else if (j == 0) {
-                    i--;
-                    builder.remove(path + '/' + i);
-                } else if ((c[i][j] & 1) == 1) {
-                    i--; j--;
-                } else {
-                    int f = c[i][j-1] >> 1;
-                    int g = c[i-1][j] >> 1;
-                    if (f > g) {
-                        j--;
-                        builder.add(path + '/' + j, target.get(j));
-                    } else if (f < g) {
-                        i--;
-                        builder.remove(path + '/' + i);
-                    } else { // f == g) {
-                       i--; j--;
-                       diff(path + '/' + i, source.get(i), target.get(j));
-                    }
-                }
-            }
+            emit(path, source, target, c, m, n);
+        }
+
+        private void emit(final String path,
+                          final JsonArray source,
+                          final JsonArray target,
+                          final int[][] c,
+                          final int i,
+                          final int j) {
+           if (i == 0) {
+               if (j > 0) {
+                   emit(path, source, target, c, i, j - 1);
+                   builder.add(path + '/' + (j - 1), target.get(j - 1));
+               }
+           } else if (j == 0) {
+               if (i > 0) {
+                   builder.remove(path + '/' + (i - 1));
+                   emit(path, source, target, c, i - 1, j);
+               }
+           } else if ((c[i][j] & 1) == 1) {
+               emit(path, source, target, c, i - 1, j - 1);
+           } else {
+               final int f = c[i][j-1] >> 1;
+               final int g = c[i-1][j] >> 1;
+               if (f > g) {
+                   emit(path, source, target, c, i, j - 1);
+                   builder.add(path + '/' + (j - 1), target.get(j - 1));
+               } else if (f < g) {
+                   builder.remove(path + '/' + (i - 1));
+                   emit(path, source, target, c, i - 1, j);
+               } else { // f == g) {
+                   diff(path + '/' + (i - 1), source.get(i - 1),
+                     target.get(j - 1));
+                   emit(path, source, target, c, i - 1, j - 1);
+               }
+           }
         }
     }
 }

tests/src/test/resources/jsonpatchdiff.json

@@ -8,8 +8,8 @@
             "original": [ 1, 2, 3 ],
             "target": [ 1, 2, 3, 4, 5 ],
             "expected": [
-                            {"op":"add","path":"/4","value":5},
-                            {"op":"add","path":"/3","value":4}
+                            {"op":"add","path":"/3","value":4},
+                            {"op":"add","path":"/4","value":5}
                         ]
         },
         {
@@ -25,8 +25,8 @@
             "target": [1,7,3,4,8,5],
             "expected": [
                             { "op": "remove", "path": "/5"},
-                            { "op": "add", "path": "/4", "value": 8},
-                            { "op": "replace", "path": "/1", "value": 7}
+                            { "op": "replace", "path": "/1", "value": 7},
+                            { "op": "add", "path": "/4", "value": 8}
                         ]
         },
         {
@@ -94,8 +94,8 @@
                         "a": [ "b", 2, 3, 4 ]
                       },
             "expected": [
-                            { "op": "add", "path": "/a/3", "value": 4 },
-                            { "op": "replace", "path": "/a/0", "value": "b" }
+                            { "op": "replace", "path": "/a/0", "value":"b" },
+                            { "op": "add", "path": "/a/3", "value":4 }
                         ]
         },
         {
@@ -128,5 +128,33 @@
             "expected": [
                             { "op": "add", "path": "/d", "value": "c" }
                         ]
+        },
+        {
+            "original": [-1, 0, 1, 3, 4],
+            "target": [5, 0],
+            "expected": [
+                            { "path" : "/4", "op" : "remove"},
+                            { "path" : "/3", "op" : "remove"},
+                            { "path" : "/2", "op" : "remove"},
+                            { "value" : 5, "path" : "/0", "op" : "replace" }
+                        ]
+        },
+        {
+            "original": [0],
+            "target": [0, 1, 2, 3, 4],
+            "expected": [
+                            { "path" : "/1", "value" : 1, "op" : "add" },
+                            { "path" : "/2", "value" : 2, "op" : "add" },
+                            { "value" : 3, "path" : "/3", "op" : "add" },
+                            { "op" : "add", "path" : "/4", "value" : 4 }
+                        ]
+        },
+        {
+            "original": [0, 2, 4],
+            "target": [0, 1, 2, 3, 4],
+            "expected": [
+                            { "path" : "/1", "value" : 1, "op" : "add" },
+                            { "value" : 3, "op" : "add", "path" : "/3" }
+                        ]
         }
 ]