[Freeciv-Dev] Re: CMA assertion

[Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>]

On Sat, Jun 08, 2002 at 09:48:11PM +0000, Guy Harrison wrote:

[ Even after reading it three times I'm not sure that I understood
everything. ]

> 
> Hi Folks,
> 
> You may want to skip to the end of this email then come back. Saves you
> wasting your time if this problem is known.
> 
> CVS 1.12.3-devel GTK CygWin/XFree86 FreeCiv
> 
> cma_core.c 1783
> 
> Machine "SD" [IP=192.168.0.1] (NT4 WKS SP6a) running one human civclient
> and civserver. Machine "HH" [IP=192.168.0.16] (NT4 SVR SP6a) running one
> human civclient and connected to civserver on SD. Six AI players.
> 
> This was reproducable at the time. Symptoms were that client on HH quit
> unexpectedly triggered by the CMA assertion at line 1782 above.
> Moreover, the client on HH could not reconnect: the moment it did so,
> the same assertion triggered again.
> 
> Spurious (very infrequent) quitting of the clients has occurred before,
> the CMA always gets a mention but I cannot verify if those were down to
> the same assertion or not. 

> Clients (one but never both at the same time to date) have quit with
> both of us playing and when one person plays with their own local
> civserver - therefore I doubt any of the network and machine info
> above is relevent - I only mention it in case someone knows better.

Network may only be an issue because of the latencies. See thread
about "(PR#1546)".

> To put it in a nutshell: CMA issues mentioned in this
> paragraph "went away" when the client reconnected thus the game could be
> continued. Obviously HH could not continue(*).
> 
> I just recreated the situation. Same machines, same connection, same
> users (ie same .civclientrc), same server running the same "faulty" game
> I saved at the time that the HH client assertion was reproducable. No
> problems at all - to the extent that the two CMA controlled cities that
> were being 'detached from' at the time of the failure, are still
> controlled by the CMA even after a couple of turns by both clients.
> 
> (*) HH could continue. HH went to make a cup of tea and some toast ;-)
> Meantime I hacked out the assertion from handle_city() in cma_core.c,
> look for /*~~~*/ below. 

> I half expected something horrible to happen as a result of this

That is the correct attitude ;)

> but HH got connected and the game was completed.

Yes this assert is there so that people report bugs back.

> <snip>
> static void handle_city(struct city *pcity)
> {
>   struct cma_parameter parameter;
>   struct cma_result result;
>   size_t len;
>   bool handled;
>   int i;
> 
>   len = attr_city_get(ATTR_CITY_CMA_PARAMETER, pcity->id,
>                     sizeof(parameter), &parameter);
> 
>   if (len == 0) {
>     return;
>   }
> 
>   freelog(HANDLE_CITY_LOG_LEVEL,
>         "handle_city(city='%s'(%d) pos=(%d,%d) owner=%s)",
> pcity->name,
>         pcity->id, pcity->x, pcity->y, city_owner(pcity)->name);
> 
>   if (city_owner(pcity) != game.player_ptr) {
>     cma_release_city(pcity);
>     create_event(pcity->x, pcity->y, E_CITY_CMA_RELEASE,
>                _("CMA: You lost control of %s. Detaching from city."),
>                pcity->name);
>     return;
>   }
> 
>   assert(len == sizeof(parameter));
> 
>   freelog(HANDLE_CITY_LOG_LEVEL2, "START handle city='%s'(%d)",
>         pcity->name, pcity->id);
> 
>   handled = FALSE;
>   for (i = 0; i < 5; i++) {
>     freelog(HANDLE_CITY_LOG_LEVEL2, "  try %d", i);
> 
>     cma_query_result(pcity, &parameter, &result);
>     if (!result.found_a_valid) {
>       freelog(HANDLE_CITY_LOG_LEVEL2, "  no valid found result");
> 
>       cma_release_city(pcity);
> 
>       create_event(pcity->x, pcity->y, E_CITY_CMA_RELEASE,
>                  _("CMA: The agent can't fulfill the requirements "
>                    "for %s. Passing back control."), pcity->name);
>       handled = TRUE;
>       break;
>     } else {
>       if (!apply_result_on_server(pcity, &result)) {
>       freelog(HANDLE_CITY_LOG_LEVEL2, "  doesn't cleanly apply");
>       if (i == 0) {
>         create_event(pcity->x, pcity->y, E_NOEVENT,
>                      _("CMA: %s has changed and the calculated "
>                        "result can't be applied. Will retry."),
>                      pcity->name);
>       }
>       } else {
>       freelog(HANDLE_CITY_LOG_LEVEL2, "  ok");
>       /* Everything ok */
>       handled = TRUE;
>       break;
>       }
>     }
>   }
> 
>   if (!handled) {
>     freelog(HANDLE_CITY_LOG_LEVEL2, "  not handled");
> 
>     create_event(pcity->x, pcity->y, E_CITY_CMA_RELEASE,
>                _("CMA: %s has changed multiple times. This may be "
>                  "an error in freeciv or bad luck. Please contact "
>                  "<freeciv-dev@xxxxxxxxxxx>. The CMA will detach "
>                  "itself from the city now."), pcity->name);
> 
>     cma_release_city(pcity);
> /*~~~*/
>       #if 0
> #if (IS_DEVEL_VERSION || IS_BETA_VERSION)
>     freelog(LOG_ERROR, _("CMA: %s has changed multiple times. This may
> be "
>                        "an error in freeciv or bad luck. Please
> contact "
>                        "<freeciv-dev@xxxxxxxxxxx>. The CMA will detach
> "
>                        "itself from the city now."), pcity->name);
>     assert(0);
>     exit(EXIT_FAILURE);
> #endif
>       #else
>       #warning "FIXME: Hacked around DEVEL assertion"
>       #endif
> /*~~~*/
>   }
> 
>   freelog(HANDLE_CITY_LOG_LEVEL2, "END handle city='%s'(%d)",
> pcity->name,
>         pcity->id);
> }
> </snip>
> 
> 
> The difference between "irreproducable" but identical situation *now*
> and reproducable but identical situation *then*? civserver looks likely.
> 
> Atm civserver's freshly loaded and "clean". Back then I left it running
> even whilst I hacked the assertion out of both clients: I did *not* quit
> civserver and reload the game.
> 
> The fact that HH couldn't stay connected is possibly a side-issue. I'm
> not familiar with the FreeCiv sources but would it be unreasonable to
> assume the assertion knobbled the client in such a way that not all CMA
> controlled cities were detached? Until I recreated the situation today I
> thought that this was the bug I was reporting - not too dramatic because
> it wouldn't quit the client in a release version. The difference in CMA
> behaviour imposed upon HH is obviously more important. Has Mr Leaky
> visited the CMA code perhaps? ;-)
> 
> I didn't consider posting the saved game would be worthwhile. I'll hang
> on to it for a few days just in case.
> 
> Thanks for all the effort you guys must be putting in developing this
> game. Very impressive!

Since I couldn't digest this out of your email: Can you reproduce the
problem?
 - always: please send the savegame and instructions how to cause the problem
 - sometimes: speculate what may have caused it
 - no: this is bad since I have nothing I can work with

        Raimar

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