sipmsgops: fix warning: ‘*’ may be used uninitialized [-Wmaybe-uninit…

[ovidiusas]

Fix the following warning for gcc version 13.3.0:

sipmsgops.c: In function ‘get_updated_body_part_f’:
sipmsgops.c:1093:28: warning: ‘p’ may be used uninitialized [-Wmaybe-uninitialized]
 1093 |                         if (it!=p) {
      |                            ^
sipmsgops.c:1019:27: note: ‘p’ was declared here
 1019 |         struct body_part *p, *it;
      |                           ^
sipmsgops.c:1100:47: warning: ‘parts’ may be used uninitialized [-Wmaybe-uninitialized]
 1100 |                 msg->body->updated_part_count = parts;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
sipmsgops.c:1020:43: note: ‘parts’ was declared here
 1020 |         unsigned int out_offs, orig_offs, parts;
      |                                           ^~~~~

[bogdan-iancu]

I'm more than happy to keep the compiler quite, but IMHO, this is a very false alarm - both parts and p are initialized and used under the same test if (type) ; this var does not change across the functions, so not sure what the compiler is detecting.

[ovidiusas]

Yes, it is a false alarm, at least for now. The compiler is not smart enough to figure out the logic around the two if's and the fact that type is not changed between the two blocks.
On the other hand, those warnings are annoying and initializing those variables is harmless.

[liviuchircu]

LGTM - let's just merge it, although it's unnecessary (the compiler should be smart enough to not report such a false problem).