Very rare server crash on creature events. #2570
Comments
|
@raymondtfr when i discovered this bug i had checked that the classes and functions were 100% aligned with the master. This was a few months ago. I'll check again. I fixed this bug on my server but it was not an ideal solution. I posted this bug here so that some acceptable solution may come up for everyone who may have come to suffer from it. |
|
As I said in the previous post, you have got to use the issue template so we can make sure this issue is present in this repository and not a side effect of sources that has been modified. Anyway, is the crash you posted above from months ago like you said? |
|
@raymondtfr 2º Mine was fixed months ago with a bad solution. 3º I will check again if this happens with the master repo, i'm downloading this now. 4º This GDB LOG is a recent crash where it happened in a server of my friend. I identified that the log was the same as mine and decided to post here already so that nobody suffers more with this bug. |
|
probably this: void Combat::doCombat(Creature* caster, Creature* target) const
{
//target combat callback function
if (params.combatType != COMBAT_NONE) {
CombatDamage damage = getCombatDamage(caster, target);
if (damage.primary.type != COMBAT_MANADRAIN) {
doCombatHealth(caster, target, damage, params);
} else {
doCombatMana(caster, target, damage, params);
}
} else {
doCombatDefault(caster, target, params);
}
}
void Combat::doCombat(Creature* caster, const Position& position) const
{
//area combat callback function
if (params.combatType != COMBAT_NONE) {
CombatDamage damage = getCombatDamage(caster, nullptr);
if (damage.primary.type != COMBAT_MANADRAIN) {
doCombatHealth(caster, position, area.get(), damage, params);
} else {
doCombatMana(caster, position, area.get(), damage, params);
}
} else {
CombatFunc(caster, position, area.get(), params, CombatNullFunc, nullptr);
}
}as we do not check if caster is valid before we apply the damage and just push the dangling pointer onwards. |
|
I did more than 2 hours of testing here and discovered new things and discovered the specific situations, I will edit the issue with this informations: Discovered: It was discovered that for the bug to occur, one must call the "monster: remove ()" within a creature with a registered event (creaturescripts), the tests were done within the "onHealthChange" event. Basic solution: Do not do it. *This issue can be closed. Because in my internal investigations, that lasted hours they ended up verifying that it was something not of the source, but of a bad programming in lua. I'm sorry for that! |
|
Hello Guys! I have discovered, after hours and hours of testing. I discovered the error and the "ideal solution" i will post here and you can fix them. SPELLS.CPP () bool CombatSpell::castSpell(Creature* creature, Creature* target)
{
if (!creature || !target) // added this line
return false; // added this line
if (scripted) {
LuaVariant var;
if (combat->hasArea()) {
var.type = VARIANT_POSITION;
if (needTarget) {
var.pos = target->getPosition();
} else if (needDirection) {
var.pos = Spells::getCasterPosition(creature, creature->getDirection());
} else {
var.pos = creature->getPosition();
}
} else {
var.type = VARIANT_NUMBER;
var.number = target->getID();
}
return executeCastSpell(creature, var);
}
if (combat->hasArea()) {
if (needTarget) {
combat->doCombat(creature, target->getPosition());
} else {
return castSpell(creature);
}
} else {
combat->doCombat(creature, target);
}
return true;
}Sorry because i never had used github before, and i'm starting now... |
|
So is this a bug in master or not? Because you say it needs a fix and you close the issue too. |
|
Yes, its a bug in master. It occurs in very specific and rare situations where monsters must be in very specific situations as well. |
Steps to reproduce
Create a monster and make it "active". That means letting the monster attack another monster with (SPELLS) *The target monster tested here, have an event onHealthChange.
Now remove the target monster with this code:
Expected behaviour
Remove the monster without major problems
Actual behaviour
If the monster is removed at the exact moment it is dropping a spell the server crashes. (Important this was only tested with spells in area).
Environment
Linux - Ubuntu 18
GDB LOGS:
The text was updated successfully, but these errors were encountered: