[Freeciv-Dev] (PR#17982) units that obsolete each other

["Billy Naylor" <banjo@xxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=17982 >

using revision 12030 of freeciv 2.1.0

a broken rndCIv ruleset had Ballista & Catapult obsolete each other,
which meant the client froze when the first city was created.

this should have been caught by the server when it parsed rulesets.

the client ended up looping forever on...

       while ((punittype = punittype->obsoleted_by) != U_NOT_OBSOLETED) {
         if (can_player_build_unit_direct(p, punittype)) {

in function...

   bool can_player_eventually_build_unit(const struct player *p,
                       const struct unit_type *punittype)

in file common/unittype.c

how to test...

modify units.ruleset so Archer & Pikemen obsolete each other, start
a game and build a city.

-banjo