fix Rare (really) core-downer fix related to rare attribute

[Gurgarath 2423]

Hello guys,

I am once again coming with a really little fix that is related to rare attribute (6/7 bonuses). This bug is extra rare because to trigger it you must have a way to add 6 and 7 bonuses to an item and you must have an incorrect field or an error in your item_attr_rare table. So this is most likely a code sanitization but it's always good to avoid such errors as I encountered people having this bug.

When you add a rare bonus, the game will fill a vector with the bonuses from the table and randomly pick one in the vector. However, if you have an error in the table, this vector will be empty and the randomization will result in doing "number(0, -1)", which is obviously incorrect and your core will crash.

For searching purposes (if someone in the future is looking for a fix), the error is this one :

Quote

number_ex: number(): first argument is bigger than second argument 0 -> -1

The fix is really simple, we must check if the vector is empty and then exit at this moment.

In item_attribute.cpp, in the following function:

bool CItem::AddRareAttribute()

Under this block of code:

	for (int i = 0; i < MAX_APPLY_NUM; ++i)
	{
		const TItemAttrTable& r = g_map_itemRare[i];

		if (r.dwApplyIndex != 0 && r.bMaxLevelBySet[nAttrSet] > 0 && HasRareAttr(i) != true)
		{
			avail.push_back(i);
		}
	}

Add the following check:

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And that's pretty much it, pretty straightforward, but instead of crashing, you will have a syserr and you will know what to check next!

Edited August 12, 2022 by Gurgarath

[WeedHex 626]

I don't use 6-7 btw this is an important fix! Thanks for sharing  GG

[AZICKO 7069]

Awesome, Amazing!

[IceShiva 144]

There is also stupid bug, You can access 0-255 array index where vaild index is 0-4,  if memory is filled at address which array points and value is < 1 with incorrect index  you should get free name change.

If you want trigger, just call net.SendChangeNamePacket(254, "newcharactername") from python. Try to decrement/increment index to find filled memory and check behaviour.

Edited August 26, 2022 by Metin2 Dev
Core X - External 2 Internal

[Intel 728]

For a second I was thinking "this crash feels familiar.." and yep

For a system I made I had not to include some items in the table and sometimes the game would crash and found out about this stupid thing as well.

Edited August 18, 2022 by Metin2 Dev
Core X - External 2 Internal

[narcisxb 25]

Ok, so this fix will make Malis Official 6/7 ATTR System FAIL every single time you try to add a new bonus. 

Any ideea why? I want to use the fix but at the same time I love his system.

Edited October 29, 2021 by narcisxb

[Hunger 464]

On 10/29/2021 at 1:50 PM, narcisxb said:

Ok, so this fix will make Malis Official 6/7 ATTR System FAIL every single time you try to add a new bonus. 

Any ideea why? I want to use the fix but at the same time I love his system.

The code above has nothing to do with the adding chance

[narcisxb 25]

38 minutes ago, Hunger said:

The code above has nothing to do with the adding chance

I literally tested the code. As soon as I commented it I could add 6/7 again. (I tested it two or three times). With this fix tou can t add 6/7 (it always fails) using that system. Give it a try yourself I was just as surprised.

Edited November 6, 2021 by narcisxb

[EnKor 42]

On 11/6/2021 at 6:18 AM, narcisxb said:

I literally tested the code. As soon as I commented it I could add 6/7 again. (I tested it two or three times). With this fix tou can t add 6/7 (it always fails) using that system. Give it a try yourself I was just as surprised.

I got 100% same error as you. But in my case it was because i add FIX before 

Spoiler

for (int i = 0; i < MAX_APPLY_NUM; ++i)
	{
		const TItemAttrTable& r = g_map_itemRare[i];

		if (r.dwApplyIndex != 0 && r.bMaxLevelBySet[nAttrSet] > 0 && HasRareAttr(i) != true)
		{
			avail.push_back(i);
		}
	}

 

Fix need to be after like he say

 

On 7/4/2021 at 2:20 PM, Gurgarath said:

Under this block of code:

	for (int i = 0; i < MAX_APPLY_NUM; ++i)
	{
		const TItemAttrTable& r = g_map_itemRare[i];

		if (r.dwApplyIndex != 0 && r.bMaxLevelBySet[nAttrSet] > 0 && HasRareAttr(i) != true)
		{
			avail.push_back(i);
		}
	}

Add the following check:

if (avail.empty())
	{
		sys_err("Couldn't add a rare bonus - item_attr_rare has incorrect values!");
		return false;
	}