Re: [boost] [property_tree] Issue: erase is corrupting the tree

9 Jun 2017

      On 06-06-17 10:32, Lukas via Boost wrote:
...
boost::property_tree::ptree loadedJSON;
    boost::property_tree::read_json("animalList.json", loadedJSON);
    auto assoc_it = loadedJSON.find("animals");
    auto it = loadedJSON.to_iterator(assoc_it);
    it = it->second.begin();
    it++; // move to second item
    loadedJSON.erase(it);
    boost::property_tree::write_json("shorterList.json", loadedJSON);
You're using erase on the wrong container.

     auto it = loadedJSON.to_iterator(assoc_it);

Here, it points into the root ptree.

     it = it->second.begin();

Now, it points into the nested ptree ("animals")

    loadedJSON.erase(it);

That's undefined behaviour. Fix:

    #include 
    #include 
    #include <iostream>

    using boost::property_tree::ptree;

    int main() {
        ptree loadedJSON;
        read_json("animalList.json", loadedJSON);

        //auto& animals = *loadedJSON.find("animals");
        auto& animals = loadedJSON.get_child("animals");

        auto it = animals.begin();
        it++; // move to second item
        animals.erase(it);

        write_json("shorterList.json", loadedJSON);
    }

Re: [boost] [property_tree] Issue: erase is corrupting the tree

Seth