initial call of xpath_node_set_raw::append()

[mloy]

for commit 21cff3b clang static analyzer does complain about line 7783

'memcpy(end, begin, count * sizeof(xpath_node));'

'_end: Null pointer passed as an argument to a 'nonnull' parameter'

I'm not sure, how this can happen. One possibility would be that nothing is in there yet. size_ is 0 and end is 0. Now calling append with begin = end_ does not allocate any memory and memcpy will be called with _end = 0 and count = 0. I'm not sure what memcpy is doing when nothing (count=0) is to be copied to NULL, but clang is complaining.

One simple solution would be checking at the very beginning whether begin_ == end_. In this case nothing is to be done => return.

regards,
Matthias