[#5] 修复越界导致的panic

Author: 520MianXiangDuiXiang520

jsondiff_test.go

@@ -182,3 +182,13 @@ func eq(a, b *decode.JsonNode) bool {
 	}
 	return true
 }
+
+func TestAsDiffsIssue5(t *testing.T) {
+	json1 := `{"A": 1, "B": [1, 2, 3], "C": [1, 2]}`
+	json2 := `{"A": 1, "B": [1, 3], "C": [2, 1], "D": 6}`
+	diffs, err := AsDiffs([]byte(json1), []byte(json2), UseMoveOption, UseCopyOption, UseFullRemoveOption)
+	if err != nil {
+		t.Error("got an error", err)
+	}
+	fmt.Println(string(diffs))
+}

lcs.go

@@ -30,25 +30,21 @@ func longestCommonSubsequence(first, second []*decode.JsonNode) []*decode.JsonNo
 			}
 		}
 	}
-	// printDP(dp)
 	start, end := len(first), len(second)
 	cur := dp[start][end] - 1
 	res := make([]*decode.JsonNode, cur+1)
+
+	// fix issue #5 (https://github.com/520MianXiangDuiXiang520/json-diff/issues/5)
 	for cur >= 0 {
-		if end >= 0 && start >= 0 &&
-			dp[start][end] == dp[start][end-1] &&
-			dp[start][end] == dp[start-1][end] {
-			start--
-			end--
-		} else if end >= 0 && dp[start][end] == dp[start][end-1] {
+		if end > 0 && dp[start][end] == dp[start][end-1] {
 			end--
-		} else if start >= 0 && dp[start][end] == dp[start-1][end] {
+		} else if start > 0 && dp[start][end] == dp[start-1][end] {
 			start--
 		} else {
 			res[cur] = first[start-1]
-			cur--
 			start--
 			end--
+			cur--
 		}
 	}
 

options.go

@@ -212,6 +212,9 @@ func computeUnChangeNode(container *unChangeContainer, path string, src, target
 
 func computeSliceUnChange(contains *unChangeContainer, path string, src, target *decode.JsonNode) {
 	for i, v := range src.Children {
+		if i >= len(target.Children) {
+			return
+		}
 		computeUnChangeNode(contains, fmt.Sprintf("%s/%d", path, i), v, target.Children[i])
 	}
 }

test_data/getDiffTest.json

@@ -312,6 +312,34 @@
       "options": [
         8
       ]
+    },
+    {
+      "name": "issues#5",
+      "src": {
+        "A": [
+          1,
+          2
+        ]
+      },
+      "patch": {
+        "A": [
+          2,
+          1
+        ]
+      },
+      "want": [
+        {
+          "op": "remove",
+          "path": "/A/0"
+        },
+        {
+          "op": "add",
+          "path": "/A/1",
+          "value": 1
+        }
+      ],
+      "want-error": false,
+      "options": []
     }
   ]
 }