[Swig-devel] [ swig-Bugs-2432801 ] bad SwigValueWrapper::operator=

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Bugs item #2432801, was opened at 2008-12-16 16:43
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Category: code generation (general)
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Maxim Yanchenko (enerjazzer)
Assigned to: Nobody/Anonymous (nobody)
Summary: bad SwigValueWrapper::operator=

Initial Comment:
Hi all,

Please take a look at the operator= in the class SwigValueWrapper:

    SwigValueWrapper& operator=(const T& t) { delete tt; tt = new T(t); return *this; }

As you see, tt is being deleted first, then we are copy-constructing a new object of the class T.

If this constructor throws an exception, tt points to the deleted object, so wrapper object becomes unusable.

What's worse, when the wrapper object is being destructed, tt will be deleted second time:

    ~SwigValueWrapper() { delete tt; } 

The version 1.1.36 still contains this bug.


The bugfix is obvious:
    SwigValueWrapper& operator=(const T& t) { T *new_tt = new T(t); delete tt; tt = new_tt; return *this; }

Thanks,
Maxim

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