[CoinUtils] Bug or no bug? (VS2010 & null pointers)

[Lou Hafer]

Folks,

     Those of you on the last TLC telecon will recall I mentioned that 
the CoinUtils unit test triggers a VS assert when built in debug mode in 
VS2010. Here are the details. The question: Is this our bug, or a bug in 
MS's debug library.

     A CoinShallowPackedVector object contains pointers to vectors of 
elements and coefficients. The default constructor sets these attributes 
to 0. CoinShallowPackedVector::operator== contains the following call:

  std::equal(getIndices(), getIndices()+getNumElements(), rhs.getIndices())

For an empty vector, this will resolve to std::equal(0,0+0,0). Some 
sample code is attached that will trigger the assert in a debug build 
and run just fine in a release build. I'll point out that VS2010 is the 
firstplatform I know of that has this problem.

     The VS debug libraries contain lots of useful code to catch errors, 
so I'm reluctant to bludgeon VS into submission by defining compile-time 
symbols to remove the checks. I was just going to just report this as a 
VS bug, but it's arguable. (As a technical defense, the MS documentation 
does state that all pointers must be dereferenceable.) So I'm putting it 
out to the community. Opinions? Is this our bug, or Microsoft's bug?

                                                                                                Lou
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