[jira] [Commented] (MESOS-2756) Update style guide: Avoid object slicing

["Joris Van Remoortere (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MESOS-2756?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14553371#comment-14553371 ] 

Joris Van Remoortere commented on MESOS-2756:
---------------------------------------------

Please see some references for object slicing:
http://en.wikipedia.org/wiki/Object_slicing
http://www.geeksforgeeks.org/object-slicing-in-c/

> Update style guide: Avoid object slicing
> ----------------------------------------
>
>                 Key: MESOS-2756
>                 URL: https://issues.apache.org/jira/browse/MESOS-2756
>             Project: Mesos
>          Issue Type: Improvement
>            Reporter: Joris Van Remoortere
>            Assignee: Joris Van Remoortere
>              Labels: c++
>
> In order to improve the safety of our code base, let's augment the style guide to:
> "Disallow public construction of base classes"
> so that we can avoid the object slicing problem. This is a good pattern to follow in general as it prevents subtle semantic bugs like the following:
> {code:title=ObjectSlicing.cpp|borderStyle=solid}
> #include <stdio.h>
> #include <vector>
> class Base {
>   public:
>   Base(int _v) : v(_v) {}
>   virtual int get() const { return v; }
>   protected:
>   int v;
> };
> class Derived : public Base {
>   public:
>   Derived(int _v) : Base(_v) {}
>   virtual int get() const { return v + 1; }
> };
> int main() {
>   Base b(5);
>   Derived d(5);
>   std::vector<Base> vec;
>   vec.push_back(b);
>   vec.push_back(d);
>   for (const auto& v : vec) {
>     printf("[%d]\n", v.get());
>   }
> }
> {code}



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