[Quantlib-dev] credit on Saturdays

[<ja...@fr...>]

If I define CDS helpers on a Saturday. The curve ref date is then the next monday.
Now use the curve to price a coupon with that Saturday (i.e. today) placed within the coupon period, that date becomes the effective start date for the coupon and the pricing fails because of the negative time requested to the default probability (see below)

I am not saying it is a bug. Something similar happens in FI defining a reference date for an index on a Saturday and calling for a fixing which now falls before the index  ref date.
 
Anyway, all this to ask you what do you think of modifying the code below
(see: ql/termstructures/defaulttermstructure.cpp)
-------------------------------------------------------------------------------
    Probability DefaultProbabilityTermStructure::defaultProbability(
                                                     const Date& d1,
                                                     const Date& d2,
                                                     bool extrapolate) const {
        QL_REQUIRE(d1 <= d2,
                   "initial date (" << d1 << ") "
                   "later than final date (" << d2 << ")");
        Probability p1 = (d1<=referenceDate()) ? 0. : defaultProbability(d1,extrapolate);//<<<<<<<<<<
        Probability p2 = defaultProbability(d2,extrapolate);
 
        return p2 - p1;
    }
-------------------------------------------------------------------------------
and similarly for the Time version.
It bypasses the negative time check by assuming survival before the curve reference date.

What do you think?

Best regards
Pepe