Merge branch 'feature/issue269' into develop

README.md

@@ -502,7 +502,11 @@ $ make
 $ ./json_unit "*"
 
 ===============================================================================
+<<<<<<< HEAD
+All tests passed (5568722 assertions in 32 test cases)
+=======
 All tests passed (5568721 assertions in 32 test cases)
+>>>>>>> develop
 ```
 
 For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).

src/json.hpp

@@ -10002,9 +10002,12 @@ basic_json_parser_63:
                     // in a second pass, traverse the remaining elements
 
                     // remove my remaining elements
+                    const auto end_index = static_cast<difference_type>(result.size());
                     while (i < source.size())
                     {
-                        result.push_back(object(
+                        // add operations in reverse order to avoid invalid
+                        // indices
+                        result.insert(result.begin() + end_index, object(
                         {
                             {"op", "remove"},
                             {"path", path + "/" + std::to_string(i)}

src/json.hpp.re2c

@@ -9312,9 +9312,12 @@ class basic_json
                     // in a second pass, traverse the remaining elements
 
                     // remove my remaining elements
+                    const auto end_index = static_cast<difference_type>(result.size());
                     while (i < source.size())
                     {
-                        result.push_back(object(
+                        // add operations in reverse order to avoid invalid
+                        // indices
+                        result.insert(result.begin() + end_index, object(
                         {
                             {"op", "remove"},
                             {"path", path + "/" + std::to_string(i)}

test/src/unit.cpp

@@ -14107,6 +14107,15 @@ TEST_CASE("regression tests")
 
         CHECK(data == json({{"key", "value"}, {"key2", "value2"}, {"key3", "value3"}}));
     }
+
+    SECTION("issue #269 - diff generates incorrect patch when removing multiple array elements")
+    {
+        json doc = R"( { "arr1": [1, 2, 3, 4] } )"_json;
+        json expected = R"( { "arr1": [1, 2] } )"_json;
+
+        // check roundtrip
+        CHECK(doc.patch(json::diff(doc, expected)) == expected);
+    }
 }
 
 // special test case to check if memory is leaked if constructor throws