A not so basic question :)

Hi
    Thanks to everyone who has been helping me with my basic questions. 
However, I have a question that is not so basic, or at least so it seems 
to me.

    Consider the following use of integrate (the integrand is singular 
in the domain) :

assume(x<1);
assume(x>-1);
f(x):=integrate(sqrt(1-s^2)/(x-s),s,-1,1);
f(x);

Maxima returns the Principal Value as :

Principal Value$$\isqrt{1-x^{2}}\*\log 
\left(-\ifracd{1}{2\*x-1}\right)+\pi\*x$$

(what's with the non-tex \ifracd and \isqrt anyway ?)

The correct answer (confirmed with a hand calculation and Mathematica) 
is simply \pi*x.

Is this a bug ?

Thanks,
MS.