Re: Segfault in side_material_production

[Hans Ronne <hronne@comhem.se>]

>While testing a new game module, I encountered a bug that I am sure was
>introduced within the last few months (I'm not exactly how long ago it
>could have come up, as I have not had time to work on it for a while).
>Looking at the backtrace (see below), I suspect it has something to do
>with the recent changes to the material display code, although I cannot
>reproduce the bug in any of the games currently in the Xconq library.
>
>The GDB message is:
>
>Program received signal SIGSEGV, Segmentation fault.
>0x08108369 in side_material_production (side=0x8459e18, m=0) at side.c:3742
>3742                                    if (user_at(x, y) == unit->id) {

Thanks! The changes to the material code were massive and did not only
involve the display, so I have been waiting for bugs to pop up. In fact, I
just found one myself: the Civ2 game would hang after one or two turns due
to an infinite while loop. I will check in a fix for that soon.

Looking at the code, I can see immediately what is wrong. This piece of
advanced-unit code was taken verbatim from run_advanced_units to make
Peter's material display work correctly with advanced untis. However,
run_advanced_units also checks first that the user area layer exists and
mallocs one if it does not. Unfortunately, this check did not make it to
the new location. It illustrates the perils of cutting and pasting code
from one place to another!

I will check in a fix for this as well later. If you want to test the fix
right away, just put these lines at the start of side_material_production:

if (!user_defined()) {
    allocate_area_users();
}

and things should work fine.

Hans

P.S. I haven't forgotten about the game modules you sent me earlier. There
were a number of bugs I had to fix, though, before I could finish the game
modules overhaul. Is this one of these modules, and do you want to update
it?