Remove AllocateElements from VariableLengthVector

[N-Dekker]

VariableLengthVector::AllocateElements just converted any possible exception from new TValue[size] to an ITK exception:

ITK/Modules/Core/Common/include/itkVariableLengthVector.hxx

Lines 204 to 216 in d66197a

	VariableLengthVector<TValue>::AllocateElements(ElementIdentifier size) const
	{
	try
	{
	return new TValue[size];
	}
	catch (...)
	{
	// Intercept std::bad_alloc and any exception thrown from TValue
	// default constructor.
	itkGenericExceptionMacro("Failed to allocate memory of length " << size << " for VariableLengthVector.");
	}
	}

It appears unnecessary for VariableLengthVector to do so. In many other cases, ITK does allow non-ITK exceptions to occur, so end-users have to deal with them anyway.

This pull request was triggered by a comment by Bradley (@blowekamp) at #5693 (comment) saying:

The utility of AllocateElements wrapping a new to throw an exception which requires additional memory allocation to perform ostringstream operations is certainly IMHO, questionable.

[N-Dekker]

Simplified the VariableLengthVector(length) constructor by removing its internal Reserve(length) call.

[blowekamp]

These changes look good to me.

[dzenanz]

Looks good on a glance.

[thewtex]

Nice!

[issakomi]

Valgrind seems to be complaining

https://open.cdash.org/builds/10917349/dynamic_analysis

[N-Dekker]

Valgrind seems to be complaining

https://open.cdash.org/builds/10917349/dynamic_analysis

Thanks @issakomi, but as far as I can see, those failures are unrelated to this PR (Remove AllocateElements from VariableLengthVector).

I see, https://open.cdash.org/builds/10917349/dynamic_analysis/11341974 says:

[ RUN      ] MaskedAssignFixture.SetGetPrint
/codebuild/output/src1970974602/src/actions-runner/_work/SimpleITK/SimpleITK/ITK/Modules/Remote/SimpleITKFilters/test/itkMaskedAssignImageFilterGTest.cxx:139: Failure
Expected: filter->GetInput() doesn't throw an exception.
  Actual: it throws itk::ExceptionObject with description "/codebuild/output/src1970974602/src/actions-runner/_work/SimpleITK/SimpleITK/ITK/Modules/Core/Common/include/itkExceptionObject.h:261: in 'TTarget itk::itkDynamicCastInDebugMode(TSource) [with TTarget = const itk::Image<float, 3>*; TSource = const itk::DataObject*]':
ITK ERROR: Failed dynamic cast to PKN3itk5ImageIfLj3EEE object type = SimpleDataObjectDecorator".

• I think this is caused by ITKSimpleITKFilters PR COMP: Update GitHub Actions from ITKModuleTemplate ITKSimpleITKFilters#11 commit InsightSoftwareConsortium/ITKSimpleITKFilters@be21024 and addressed by ITKSimpleITKFilters PR Update tests for throwing exception with inputs ITKSimpleITKFilters#25 However, as @blowekamp remarked at Update tests for throwing exception with inputs ITKSimpleITKFilters#25 (comment), filter->GetInput() may or may not throw an exception, depending on whether or not it's a Debug build.

[issakomi]

Valgrind seems to be complaining

https://open.cdash.org/builds/10917349/dynamic_analysis

MaskedAssignFixture.SetGetPrint failed, I am talking about other tests with Valgring defects:

==16204==    at 0x484A2F3: operator new[](unsigned long) (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==16204==    by 0x426380: VariableLengthVector (itkVariableLengthVector.hxx:32)

==16204==    at 0x484A2F3: operator new[](unsigned long) (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==16204==    by 0x41FC94: itk::VariableLengthVector<unsigned char>::VariableLengthVector(unsigned int) (itkVariableLengthVector.hxx:32)
==16204==    by 0x42082D: itk::VariableLengthVector<unsigned char>::VariableLengthVector(itk::VariableLengthVector<unsigned char> const&) (itkVariableLengthVector.hxx:62)