[reSIProcate] Multiple provisional with the same SDP: bug or feature?

[Robert Szokovacs <rszokovacs@xxxxxxxxxxxxxxx>]

Hi,

We have  a B2BUA based on resiprocate and we noticed that if the "c" leg (the 
one we call out to) sends a 183 with SDP and then a 180 without, we pass the 
"a" leg (the one originated the call) the 180 with the SDP from the 183 
included. This is not the desired behaviour, since there are some 3rd party 
devices that doesn't seem to tolerate this.
This happens because we call ServerInviteSession's provide[Answer|Offer]() 
before calling provisional() for the 183, and then calling provisional() for 
the 180, and have no way of telling resiprocate not to include the SDP. The 
problem is that according to the comments in ServerInviteSession.hxx it is not 
necessary:
/** Called to set the offer that will be used in the next message that
          sends an offer. [...] */
      virtual void provideOffer(const SdpContents& offer);
(same with provideAnswer)

We interpreted it as "the next and only the next" message will include the 
SDP, but the code doesn't do that way. Is that the correct behaviour? If it's 
a bug, which way should I look for solution? Should we empty the 
mCurrentLocalSdp & mProposedLocalSdp after sending it? Should we transition to 
a state that doesn't call setSdp() in sendProvisional() (which state?)

Any help is appreciated!

TIA

br

Szo