Valve explains Dota 2’s most explosive bug

Dota 2 bugs are everything from funny to frustrating, but Techies’ Sticky Bomb bug is one of its silliest and most chaotic, and Valve explains how it happens.

Dota 2 - Techies, a pair of yellow creatures with wide, gap-tooth smiles.

Dota 2 is a huge game with hundreds of characters, played by millions of people every day, so it’s not too surprising that Dota 2 bugs pop up from time to time. Valve is usually pretty good at staying on top of them, but some are more dramatic than others. One of the most fun and explosive slip-ups to make its way into the MOBA this year is the Dota 2 Techies Sticky Bomb bug, and now the team explains how it came about.

In a new recurring feature called ‘Between the Lanes,’ the Dota 2 team discuss “some of the challenges, bug fixes, and happy accidents we encounter while working on a game as unique as Dota.” First up is the Techies Sticky Bomb bug, which let players using the game’s most infamous hero create a veritable army of Sticky Bombs, which they could then control and move around the map to overwhelm foes with the swarm’s explosive payload.

This actually dates back to the big Techies rework in 2022, which Valve says “created a bug where Techies’ Sticky Bombs didn’t expire, and in some cases became controllable by the casting player.” However, this wasn’t actually a problem at the time, because “there were no circumstances where the bug could actually occur in a match.” That all changed with the massive Dota 2 New Frontiers update earlier this year, however.

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Simply put, Valve explains that Sticky Bombs were based on the original Remote Mines used by Techies. Because these could be manually detonated, they were designated in the game’s code both as able to use abilities, and as a controllable unit for the person playing Techies. However, the sequence of actions taken by the Sticky Bombs meant they were never in a position to actually receive or act on those orders.

This changed with New Frontiers because of the introduction of the Twin Gates, which let players quickly travel between opposite corners of the map. Unlike most other interactable map entities, Twin Gates can actually be used by non-hero units, because boss monster Roshan likes to take a trip through them to visit his holiday home on the other side of town.

All of this combined to create a situation where the Sticky Bombs could attempt to use the Twin Gates if the Techies player clicked on them immediately after tossing the Sticky Bomb out. This put the Bombs in a state that interrupted their typical behavior, which then left them idling and suddenly able to be directly controlled, as their normal preventative measures were no longer stopping players from giving them orders.

And thus, a bug is born. Delightful! Fortunately for Valve, once it realized the problem, the fix was pretty quick. There’s actually never a reason why the Sticky Bomb needs to be player-controlled, so they simply removed the tag marking it as a controllable unit, which put a stop to the issue.

Dota 2 - a group of controllable Sticky Bombs stand around one of the MOBA's Twin Gates.

“As with so many bugs, 99% of the time spent fixing it is usually in trying to track it down,” Valve says, “The actual solution usually boils down to changing a single line of code – possibly the same line of code you wrote to fix a previous bug.” Thankfully the situation is resolved, and the joyous but ultimate broken trick is no more. “Now we sit and wait to discover whatever new bug we created by deleting that line of code.”

It’s almost time for Dota 2 The International 2023, so catch up on all the details. We’ve also put together the best Dota 2 custom games, if this taste of chaos has you wanting something even more ridiculous than what the base game provides.