[Freeciv-Dev] (PR#4781) phantom units showing up on client

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

[glip - Sat Aug  9 19:45:37 2003]:

> On Thu, 7 Aug 2003, Guest wrote:
> 
> > 
> > Sometimes enemy units are visible, but aren't really there. That is, my
> > 
> 
> Ha, I got it (well, at least one instance):
> 
> handle_unit_attack_request sends combatants' info to many connections, 
> which isn't a mistake.
> 
> What is a mistake is that the client doesn't remove this information 
> properly: in client/packhand.c handle_unit_info, if unit is not new
> something like
> 
> if (!(tile_get_known(punit->x,punit->y) == TILE_KNOWN)) {
>   cient_remove_unit(punit);
>   refresh_tile_mapcanvas(dest_x, dest_y, FALSE);
> }
> 
> should be added.
> 
> This should be done by somebody who knows what is happening in this 
> function, and tested too.  The current behaviour when both combatants are 
> displayed for a brief moment even though one of them might be under cover 
> of fog should stay imo.
> 
> I attach a savegame whcih should be helpful.  Connect to Israelis 
> and Carthagians.  Attack French explorer with Carthagian warrior.  The 
> warrior will be briefly displayed on Israelis' client (center on Israeli 
> explorer).  When you move Israeli explorer, you can see the phantom 
> Carthagian warrior which is no longer.

Unfortunately it's not quite that simple.

I suppose the server must send a unit_info packet to the client to tell
them the unit exists, even though the client can't see it.  Then a
unit_combat packet is sent that tells of the combat itself.  So if the
_client_ is to remove the unit, it should be done at the end of the
unit_combat packet.  The attached patch does this, and fixes the problem
for your savegame.

But, I think the server should send the unit disband packet (or does
this happen as a result of the unit_combat packet?).  Or maybe it
already does, and the client ignore it because the unit is not visible?

jason

phantom_unit.diff
Description: phantom_unit.diff