I've decided to make an annotated checklist (similar to the old list started by Librarian) of the bugs that are currently existing in D2, this includes all bugs known that I know of (and have confirmed to exist via code analysis!) - Note, when I refer to hp anywhere in this topic, I refer to _real_ hp values (aka 256ths), when I say life, I mean the value shown on-screen. Also I have only listed bugs that will occur in vanilla (so stuff like crashing weapon / armor racks are not included, because they work like they were meant to work!)




[New Stuff]
- This is by far, and I mean really by far not all of what I found since I updated the topic the last time.

Missile AR, again - The bug mentioned further down that monster missiles recieve more then their intended AR was a typical failed attempt to 'fix' a deeper laying problem, as you know monsters get AR that depends on their current mode, since the AR is read from the monster when the missile collides the missile could remain without AR if the enemy mode ends before it hits. The fix for this is simple, just storing the active AR on the missile when it gets created (like damage is already).

Molten Boulder Desync - Molten boulder is designed to detonate only when it collides with units flagged as large, and once it expires, however due to a bug in the SMoveFunc it will only detonate if it collides, and not when it expires, so it produces ghost-fire.

Druid Melee Skills - Several of them (Rabies included) check the Attacker-Defender routine twice, so it actually is twice as unlikely to hit.

Missile Desync - On the client missiles are one frame behind the server, this was semi-fixed by not checking for collision flags and skipping over frames if the missile is launched by the current client, the missile will still 'work' on the one extra frame however, which can make things like chain lightning on close range rather unpredictable.

Knockback - a plethora of problems, knockback will sometimes not update the flag telling the game the unit was moved from one room to the other, additionally it seams theres a wrong hardcode which applies the EndOfKB behavior of sandleapers for all other monsters and the one intended for normal monsters to sandleapers. Units were meant to stall for 15 frames after KB to give the client a chance to catch up (ie avoid desync), but this is done only for sandleapers, not surprisingly, making it choose that behavior for everything perfectly syncs KB in MP games.

Doors - The problem with doors becoming desynced is not related to communication or whatever else, the problem comes from the borked anim hardcode on the client (doors have open and close anims), the game doesn't handle this properly and screws up, leaving the door stuck in the wrong mode clientside.



[New Bugs]

Waypoint Memory Leak - the WayPointRoom appended to pObjRegion (a new segment created each time you activate a waypoint by visting it, not clicking on it), isn't freed properly should more then one waypoint be activated at about the same time (this CAN happen in MP games). Only one node is freed, but the index is set to NULL, thus leaving some memory leaked.

Kick Skills - Several bugs here, the client skill-triggering validation does not check if you're already in PLRMODE_KICK (which is a bug), this is what causes all the bugs associated with these skills (there is no AR bug with them, this is only a display glitch at best). The result of this bug is that the skills will not perform an attack server side until you let go of the mouse button, since they ge re-initiated every frame for as long as you hold the button.

Kick Skills Part II - Added 5th June, 2008, some more bugs on Dragon Talon, it attacks twice every "hit" (the dispatcher is called twice, ofc the skill is so bugged in vanilla that this would go unnoticed without first fixing the broken srvStFunc), the evaluation for knockback chance is bugged, it looks like it originally was supposed to factorize the mLvl and cLvl of target/attacker like other skills, but ends using the mLvl of the target for both factors (which means not matter what you attack with it, the outcome of this formula will be the same). (The formula currently is: ((mlvl + slvl) - mlvl) which will always result in slvl).

Kick Skills Part III - Added 7th June, 2008, some more issues with kick skills, due to incorrect code in the default melee damage creation func, kick skills will recieve elemental damage from weapons. Caused by a missing return statement. (this is evidently a bug, first the state of both weapons is set to inactive, it should exit after this, but it continues to the 'normal' code that activates one of them again if the player can dual wield --- which assassins can).

Psychic Hammer - copy/pasted code from Dragon Talons knockback section, with the same formula bug on (using mlvl twice).

Kick Damage Bonus - This stat isn't really used in vanilla, but the bonus is added twice instead of once, so +1 is in reality +2.

Power Strike Bug - The power strike SrvStFunc ignores the attack rating bonus from skills.txt

Smite Bugs - It wasen't ever meant to hit all the time, they do call the attacker/defender routine , the problem is that they ignore the results of this, probably because they confused AND with OR. Smite also does not set unitflag #64 which tells the game a skill has been executed successfully (which will cause all kinds of glitches that may seem irrelated), finally. Smite used by monsters uses the damage specified for mode A2, even if they didn't use A2 to launch the skill (and even if they have no damage specified for A2).



Airstrike Bugs - New (but old nontheless)
I forgot to list these two bugs before, the Freezing Catapults in act V don't do anything because the code for their collision functions is broken (I never bothered to look into what exactly is broken, but my guess is that the general radial AoE redesign in v1.10 broke this). The Hell Meteors (stuff in river of flame) is entirely broken, that is meteors flash around the screen but never land, and when they land only rarely explode, and when they explode they spawn just 1 flame, instead of a fire patch (like meteor, and like they worked before v1.10)



Boss Event Screwup

Boss events that are delayed by a timer (Poison Death, Cold Enchanted, Lightning Enchanted, Firegolem Explosion, Fire Enchanted, Lightning Nova on death and others) all use the same timeout Id, as a result each single time a timeout is being set, all of these events will execute their effects.


Client Do Func Bugs

The client will continue executing the ClientDoFunc for skills even after you go into hit recovery, which leads to blank zeal swipes and ghost missiles that do not hit anything because they don't exist serverside


Stuck-age Bugs

After using certain skills (Frenzy, Leap Attack, Whirlwind) the player can get stuck in place, this happens (to my knowledge) when you start using the skills in the very moment you are hit by an attack and the server changes your mode to hit recovery, because the client keeps executing the do func (related to previous bug) you remain stuck in this state for eternity


Unowned Skill Summon Bug

Summons created by skills you do not have (CTC, Oskill) will vanish after random events take place because the summon rehashing function is called in places that shouldn't call it (such as when drinking potions other then rejuv potions)


Ethereal Item Bug

The defense bonus to ethereal items will increase every time the item is used in a cube recipe that alters item flags, this happens because the defense stats are saved directly on the item


Monster Damage

Monster elemental damage is completely broken, the function Blizzard uses to generate monster stats does not discriminate between the different elemental damage columns, as a result the game will use the damage from the first column for all elementally enchanted attacks the monster can do (=Gloam Bug), this is further complicated by the feature that elemental damage done by monsters is effected by their critical hit chance.


MissileSrcDamage Bugs

The spell casting vipers added by v1.10 will append their melee damage to the poison clouds they release, this isn't really a bug (the code works like it should!), but careless design


Leeching Bug

Melee attacking monsters that do life, mana and stamina steal damage do twice the amount of damage indicated (this means that those bugged mana drain bosses actually do 512 times the proper damage!!), in the function that creates pDamage after an attack hits incorrectly adds the new value to the old value, instead of setting the old value to the new value!


Generic Damage Bugorama

Skills that use SrcDamage values other then 128 do not have the proper amounts of damage as SrcDamage is incorrectly (and inconsistently) applied throughout the code which may lead to damage being reduced more then it should, on missiles the situation is worse as some damage types are not reduced at all.


Item Damage Order

This is more of a design flaw then a bug, the game will apply the ED% bonus after other damage boni have been applied, this is not a bug because there is no way to change the check order in vanilla (weapon damage and extra weapon damage use the same stat, so changing the order would break ED% completely).


Missile Poison Damage Bug

Poison rises its ugly head again, blizzard confused Poison_Count stat with Poison_Length when it comes to applying SrcDamage to the missile damage, as a result skills like Multishot (that have SrcDamage other then 128) will end up with invalid poison duration when you have more then one poison source (this is related to the above but deserves a seperate place)


Monster Regen Bug

Monsters that are low on max hitpoints will end up having no life regeneration (this applies to quill rats and other low enemies on normal only), the calculation used ((hp / regen) << 10) will result in 0


Crushing Blow Bug

Players that have >99% physical resistance can become immune to crushing blow, as the function used for Crushing Blow does not discriminate between monsters and players (it should be capped to 50% here as well!) when it checks for resistances to lower the damage you take from crushing blow


Summon Stats Bug

Summoned monsters will recieve extra attack rating and defense equal to 100% of the value listed in MonLvl.txt for their mLvl (noratio is ignored)


Attack Rating Bugs

Monsters that use ranged attacks that require attack rating (Quill Rats, Blow Pipers etc) have twice the attack rating they should have (due to a incorrect assignment in the attacker / defender code)

Throwing and shooting skills that add an attack rating bonus to the missiles do not add their bonus (it passes 0 to the function instead of reading the bonus of the missile)

Blessed Aim and Penetrate use the same state, as a result the two skills can cancel each other out because they will replace each others state statlists


Life / Damage Shifting Bugs

There are many places in the code where Blizzard forgot to handle life and damage in 256ths, this results in 1/256 life assigned to units, which can cause all kinds of weird behavior


Evil Urn Spiders

They were not meant to spawn spiders, the same column (Objects.txt -> Par7) is used for different purposes on the client and the server, the value on the server has to do with the chance of spawning bosses, on the client values other the 0 in this field will spawn spiders or rats (255 = rat, anything else but 0 = spider).


Invalid Objects

The ObjGroup data listed in levels.txt is very broken, some groups have a chance of 0% to spawn, other groups do not contain objects and thus just decimate the amount of objects spawning in the area


Curse Resistance Glitch

Curse Resistance is checked in the same function that handles most time-based statlists assigned to units, except for a few cases that are handled specially it will be applied to every time-based statlist, which means it will reduce the duration of positive effects as well


Trigger Event Bug

The Frozen Horror arctic blast incorrectly triggers events, which can lead to a sprite overflow when the skill is cast on a Sorceress using Chilling Armor


Cleansing Glitch

Less severe, but still, cleansing will also reduce the duration of shrines because shrines are incorrectly flagged as curses in states.txt


MonType.txt Lookup Bug

All lookups for records in MonType.txt done on the client will incorrectly use the record count from MonProp.txt


Boss Picking Column Glitch

This isn't a real bug, but then again it does cause some likely unintentional behavior (such as generating nests as bosses), the game uses nmon instead of umon to pick bosses after normal, which means they are picked out of the normal enemy pool instead of the special boss pool


Fires Magic Arrows Bug

You don't actually fire magic arrows, they only look like magic arrows on the client, in reality they are just regular arrows. Note: the srvdmgfunc is called properly, but any other appended missile functions are not called (the loss of ammo is not controlled by special functions but by a boolean in missiles.txt).


Magic Pierce and Magic Skill Damage Stats

These stats, while not being used by vanilla, are inconsitently referenced by the code, so should they chose to use them in the future without fixing this mess, expect new bugs


Multishot Lag Bugs

Several boss death effects do not have NoMultishot set to true, as a result encountering and killing them if they have the Multishot UMod will spawn their death effect up to five times (Shenk et al.)


Oblivion Clone Bug

Extra oblivion knights added by v1.10 and v1.11x do not recieve the proper components, which means they show up with mismatching glow around their hands, this is caused by them not checking the BaseId, but rather checking the HcIdx


Crafted Items Bug

The game does not display affix-colors for Crafted Items because they were forgotten in the item-color function inside D2Client.dll


Drop Limit Bug

The fix to the old chest glitch has broken some act boss drops, some act bosses were originally meant to drop 7 rather then 6 items


Ai Bugs

Many monster Ais are incompletely coded, for example the Fetish Shamans will never use their Fetish Aura skill and Oblivion Knights do not attempt to heal allies (in the later case the game even attempts to pick a target for healing, which needlessly wastes cpu cycles because the return is discarded right away), many other Ais have potential to jam up, this section is too large to cover in detail, theres just verymuchalot of broken stuff here...


Homing Missile Bug

The target seeking flags used on the client and server for missiles that automatically seek a target (Guided Arrow etc) are not identical, this can sometimes lead to different units being targeted on both ends, which makes the missile vanish


Palette Shift Bug

The last batch of palettes in RandTransforms.dat is never used by the game because they forget to adjust the index in the only lookup that really matters (the one in the drawing function)


Self-Resurrect Bug

The self-resurrect ability of the Reanimated Hordes incorrectly accesses the Ai-Parameters which leads to them almost never resurrecting (or taking very long to resurrect) --- this isn't really a Ai bug because this isn't part of the Ai-code, this is a MonUMod (AiAfterDeath)


Trapped Souls Bug

Trapped souls that drop their items with a delay (those that go up in flames when you touch them), do not take into account your characters gold and magic find, they pass NULL to the tc function


Copy/Paste Is 1337 Bug

Blizzard copy/pasted that Desert level for the uber quest in v1.11x, and forgot to set the Waypoint Id to -1 (255), waypoint lists are constructed clientside, and we all know what that means


Diablo Clone Bug

Uber Diablo (or the Clone, one of the two) doesn't use the diablo-mode chart entry, instead he uses the same normal monsters use, which can cause unexpected problems


Treasure Class Upgrade Bug

This is a critical bug, the function does not check whenever it is reading the last record inside the TCEX BinImage, as a result it can end up traversing random memory until it asplodes


Poison Cloud Bugs

Some poison clouds have invalid hitclass set in Missiles.txt, as a result they play the same sound like a javelin does when you walk into them, which can be very annoying. The trail left by Plague Javelin doesn't do damage, because of a typo in the serverside movement function


Mana Burn Bug

Melee attackers that have the mana burn boss mod will incorrectly deal 256 times more manasteal damage then they should (the damage is shifted twice instead of once)


Quest Drop Bug

Some quest flags are being reset when they shouldn't allowing you to recieve Andariels and Duriels quest drop infinite times until you visit Act II.


Fangskin Bug

The treasureclass assigned to Fangskin on hell doesn't exist


Monster Chain Bug

The guest monsters added in v1.11b (and also the Diablo Clone) have broken chains which will lead to various (but not really noteworthy) glitches


Broken Runewords

Some of the property codes assigned to the v1.11x runewords are not spelled properly (which will make the game quit assigning stats after the bad property is reached, which in itself is a bug, it should just skip it, like it does elsewhere)


Various Tileset Flag Bugs

There are several places where the walkable flags in the tiles are not properly set, allowing players to go to places they shouldn't be able to, this also applies to monsters spawning on inaccessable islands (for example in the Act III sewers)


Affix Glitches

Some items spawn with affixes they shouldn't recieve (such as circlets listed for both series of damage reduction, instead of only the first one meant for circlets), Small Charms should be able to recieve the Lucky prefix, instead the small charm version is assigned to large charms, some affixes have invalid itemtypes listed, which prevents them from spawning on those types (staves noteably listed as staff and not staf). There also are some problems with the qLvl and reqLvl of some affixes (ex. King's and Master's have the same qLvl and among the resistance affixes the strongest affixes have a lower level then a bunch of weaker ones available on the same items [IIRC] <keyword rods>), another incarnation of this is the Lizard's prefix on small charms, there are two variants available at the same qLvl that add different values (rather then one affix only), the weaker one was meant to be replaced by the later (I assume this because thats how some others like this are set up, the masters of copy/paste just forgot to edit the line...)
New ones added I forgot before


Uber Quest Items

The Uber Quest Items drop in single player as well, where they are completely useless (quest drops like these should be hardcoded...)


Intelligence Wrap

The AiParams for some monsters (Vampires noteably) are incorrect, leading to the earliest species being more aggressive then the end-game variants, the Guest Monsters do not have their Ai adjusted at all, which means most of them act like Act1-2 enemies


The Unspellable One

That NPC who's name nobody can properly spell in Act III uses a MagicLevel of 1 for everything because Blizzard too cannot spell his name (the column header has a typo in it)


Privilege Bugs

Certain things are handled clientside that should never be controlled by the client, for very obvious reasons I wont mention what, because these things are presently not known to the armies of seething scriptkiddiots and I have no intention to feed them.

nice list maybe some links to fixes and/or threads might help... btw what about the belt bug, perm store bug, catapult bug...

None of those has any influence on regular gameplay (catapult + permstore aren't actually bugs, we just call them bugs because they interfere with changes --- in a vanilla context the code works exactly like it was intended).

PS: Most of the fixes to the above are either in my fixed txt files or require extensive revisions of the code (the more minor ones I posted in CE)

Heiho,

thanks a lot for this one :-)
I've linked this post to the Basin. Surely some questions will arise ;-)


shouldn't this read as MonLvl.txt ?-/



this one's new to me. I only know the property 'fires exploding arrows' won't work on Rogue hirelings.
Or don't you refer to the property 'fires magical arrow', but to a CtC effect from magical affix pool?

mode chart as in NU, WL, A1 etc?
Will lead to desync, if I've understood correctly.

Yes, thanks




The thing for hirelings is not really a bug, keep in mind hirelings aren't players, monsters use a different function to launch missiles (their missiles are independant of their equipment), players that use missile weapons will use the missile granted by either to 'Fires Magic Arrows' or 'Fires Explosive Arrows' properties, and if none of these is present fire Arrows (if they use a bow), and by default fire bolts (aka it doesn't matter if they use a crossbow, bolts are the default missile [or was it arrows, can't remember, changed this code ages ago]) --- what happens is that when you have the 'Fire Magic Arrows' property you may expect them to work like magic arrows (convert % physical to magic damage) but they won't because they only use the graphic of the magic arrows. (The Explosive arrows property works).




Look for my post about SplGetModeChart and what it does (should be in CE [or GMM] it explains this far better then I could repeat here (again, changed this centuries ago, made stuff use my own mode chart code)


---

PS: Forgot adding the Monster-Leeching bug, its added now

---

EDIT: Just a note, the extra AR/AC on summons is in addition to their base defense / ac. Thats to say, if you give a summon 1000 ac in monstats (and it has no ratio), it will recieve 1000 + MonLvl[type][diff]->ac

EDIT2: Added another more generic one, which I cannot (and will not) go in-depth over

Heiho,


the Basin folks already go spare ...
I'm sure there was a testing back in the days when it showed that 'fires exploding arrow' property won't work on Rogues, and 'fires magical arrow' property worked.
I mean, it's not that hard even without modding. Give a Rogue such kind of bow, strip her off elemental damage, watch if she can hurt PIs without using her skill.

And really lots of players including myself have relied on Witchwild String as backup weapon against PIs ... it's now hard to get told it was just for graphics.
Sure, WWS also triggers Amplify, but this needs quite some time since 1.1x to happen.



found it, in CE :-)

I posted about the Magic Arrows existing only client-side stuff about 3 years ago --- what happens is that serverside after D2 calls the 'GetAmmoType' function it has some legacy code left from pre lod days, that tells it to not execute any non default functions , I originally noticed this when I changed the magic arrow to do poison damage and the ones launched by the property did plain physical damage only. --- See D2's client/server architecture like the matrix, what you are told to see by D2Client.dll is not whats really there.

EDIT: digging it up again:



When the function returns MISSILECLASS_MAGICARROW it will pass 0 for the 'execute server functions' BOOL (which means the missile will only execute the default code, instead of what it gets assigned). I'll have to do a check at some point and see if this also applies to the damage-functions because I the old tests were only with srvhit/srvmove to clear this up completely though.

how about the bug when your character gets hit so your next successful offensive action immediately after does no damage.

Is it something to do with the fend skill 'fix' ?

All these types of bugs are based on this

---

EDIT: Did a preliminary test on Fires Magic Arrow property and only the SrvDmgFunc is called properly, so for a vanilla context it is only halfway bugged inasmuch as that there is some code that appears to be legacy taking effect that shouldn't exist anymore (at least it looks very much like legacy code), so everybody can relax (at least until I can do a more throughout test on the issue ) and keep their old setup (and I can finally resort back to using this thing myself ).

Has anyone successfully fixed this bug? If so, where might I find info on such a fix, as my searches thus far have proven fruitless.

Jason

Ofc, I fixed every single bug mentioned in this topic
The fix for that one is rather simple, I posted it in CE long time ago.

...



After a few more moments poking around the code I used to replace Blizzard mess originally, I managed to resolve this problem as well Thats 1337:0 Me. Vs. Blizzard

I may have missed this one in the thread, and it definitely affects gameplay.

In A2 there is a standard dungeon room which is a dead-end room with a fince-like deal in the middle of the room. There are two rat's nests inside the fence area and a third one outside (one the side opposite the door). Clicking on the rat's nest that is in the corner of the fence often moves the player to a spot between the nest and the fence corner, and then the player is stuck and cannot move, except to turn around in a circle on one spot.

The mention of this in your 'Key Features' thread reminded me that there was a bug not listed I should post.

Elemental mastery applies to elemental damage from items and buffs for melee attacks only, not for anything missile based.
In vanilla, this would be most noticable for enchantresses (due to Firemastery) and maybe Venom users (if they have TO's gloves and/or Bramble).

This is listed it's under damage bugs. The problem with missiles not being effected by +% elem damage is not consistent, some of them are others aren't (missiles that use SRCDamage aren't effected, except for the skill based portion of their damage).

Blizzard did it the wrong way, they check for elemental mastery on the missile itself when it hits, but the missile never gets those stats assigned on it when it gets created (and if they did, they'd be applying the mastery to the skill damage twice). I've fixed this alongside all the other damage bugs

As for it effecting elemental damage from items this isn't a bug. The code is designed to work like it does in that respect.

who is the unspellable one, the npc, in act three/

Hralti which is incorrectly spelled Hratli (and various other ways) by many people, inc. those who created Weapons.txt and Armor.txt (which makes the txt parser fail to read the mispelled columns so the minimum level of whatever he sells ends up being iLvl 1, instead of 20).

iirc,
is incorrect, someone did a test, and you just have to click on a NPC in the town the boss is in (eg heal yourself @akara) then visit andy, then heal you, then visit andy, ...
and every time you gain the Questdrop. Beat me if i'm wrong

Is there anywhere I can go to get all the fixes for the bugs listed but not modify anything related to vanilla D2?

I've gotten the fixed text files written by Nef, I was wondering were I could go for the code fixes. Maybe someone should just put all those fixes together and make an unofficial Diablo II v1.12 patch.

There are a couple bugs I found that aren't on this list.

1. Assassin kick damage isn't shown on set boots.

2. Mercenaries will only go up to their base max life with their natural regen. However, once something brings their life above the base max, it will resume regenerating up to the full value. Here's an example to better explain what I mean:

-Your mercenary has 100 base life and +15 from equipment, for a total of 115 life.
-He gets beat around some and ends up at 75/115.
-Natural regen kicks in, but stops when his life gets to 100 rather than the full 115.
-It won't go past 100 until something heals him (regen on items, potions, NPC, life leech, etc.). Once above 100, natural regen will resume and take it up to the full 115.

I remember a discussion about minimum damage exceeding maximum damage on items through enchantments would be bugged and neglecting the minimum damage. example a phase blade base damage 31-35 with minimum damage +10 would result in 41-42 damage, but the bug would mean there couldn't be more than 35 damage dealt ...

does anyone remember this discussion and could please point me to the topic ?

A not so serious bug not listed is that shrine reset timers are incorrect, blizzard uses 1200 frames in a minute instead of 1500, so all reset timers are off by 1/5th(this needs code to fix). Damage has many bugs, so your best bet is the search function

sadly it's not because "mindam", "minimum" and "minimum damage" result in hundreds of topics. the search function fails here.

This list should be posted in the patch 1.13 suggestion topic, I guess it would be of great use for the developers, if they want to fix bugs.

patch 1.13 suggestion topic

Blizz devs reads those forums and they are very aware of what bugs that are in their own game

Just cause they are aware of them doesn't mean that they will fix them, losts of these bugs have been around for years, they just get ignored(one or two are even from classic!)