I observed a code clone from the following files.

function : mpd_qexp @ (file: "Python-3.3.0a4/Modules/_decimal/libmpdec/mpdecimal.c", line: 4092)~4165
function : mpd_qln @ (file: "Python-3.3.0a4/Modules/_decimal/libmpdec/mpdecimal.c", line: 4525)~4612

In the first few lines of this clone, the function mpd_qexp only calls mpd_setspecial when mpd_isnegative is false while the function mpd_qln calls mpd_setspecial independent of the value of mpd_isnegative. I wonder the checking is necessary in the function mpd_qln. The source code is included in the attachment. Hope it helps.

The code looks fine to me.

> In the first few lines of this clone, the function mpd_qexp only calls 
> mpd_setspecial when mpd_isnegative is false while the function mpd_qln 
> calls mpd_setspecial independent of the value of mpd_isnegative.

That would probably be because exp(-infinity) is 0, which isn't a floating-point special value, and ln(-infinity) is NaN, which is.

In general, I don't think this kind of report is terribly helpful unless you've also examined *and understood* the code, and based on that understanding you've established that there's a high likelihood of a real bug.

> That would probably be because exp(-infinity) is 0, which isn't a
> floating-point special value, and ln(-infinity) is NaN, which is.

Actually, looking at the code, mpd_setspecial is called under exactly the same circumstances (namely for +inf) in *both* cases; for -inf, the exp code calls _settriple, while the ln code calls mpd_seterror.

Mark has already said it all. -- Ken, I want to add that in the case
of _decimal it's pretty easy to test any suspected misbehavior against
decimal.py. This would have shown very quickly that there is no bug.