Possible NULL pointer deferenced (src/interfaces/libpq/fe-exec.c(line 563)

Hi Mark,

please, can you take a look?

This possible bug was appeared before, see at:

1. https://bugzilla.redhat.com/show_bug.cgi?id=879803

The trap still persist, in HEAD see:

src/interfaces/libpq/fe-exec.c (line 563)

/* If there's enough space in the current block, no problem. */

if (nBytes <= (size_t) res->spaceLeft)
{
   space = res->curBlock->space + res->curOffset;
   res->curOffset += nBytes;
   res->spaceLeft -= nBytes;

   return space;
}

The res->curBlock pointer possibly, can be NULL here (line 563).

See at:

src/interfaces/libpq/fe-exec.c (line 585)

if (res->curBlock)

The path is res->curBlock be NULL and res->spaceLeft > nBytes.

If res->curBlock it not can be NULL, inside pqResultAlloc function, why is verified against NULL at line 585?

regards,

Ranier Vilela