TiGL crashes when <guidecurves> node has no children nodes.

[AntonReiswich]

Bug description

TiGL crashes when node has no children nodes. This shouldn't happen. Insted, an error message should be printed.

[joergbrech]

This only happens for wings and not for fuselages. The problem is that CTiglWingBuilder::SetFaceTraits requires the guide curve parameters as argument. Internally it checks wether the guide curve parameters are empty or not, so that is fine.

The problem arises when CCPACSWingSegment or CTiglWingBuilder query the guide curve parameters to call SetFaceTraits: This indirectly calls CCPACSGuideCurves::GetRelativeCircumferenceParameters which has an implicit assumption that the parameters relCircs are not empty:

tigl/src/guide_curves/CCPACSGuideCurves.cpp

Line 107 in 45a9428

if (std::abs(relCircs.back() - 1.0) >= 1e-3 ) {