Bug splits ETH testnet into two

The year 2022 started with the cryptocurrency market showing a strong pullback and, to further complicate the scenario, a bug ended up splitting the ETH testnet.

Bug splits ETH testnet

More precisely, an issue with ETH 2.0’s Kintsugi testnet caused a fork in at least three different networks.

This makes this network take about three days without being able to validate the blocks correctly.

As reported by Marius van der Wijden, the problem was due to a bug-checking test on the network, whose tool is known as Fluzzer.

This tool aims to create invalid blocks by changing certain characteristics. The objective is to verify if the validators can identify the failure and invalidate the block.

However, it appears that some of these validators, running clients like Nethermind and Besu, identified bad blocks as correct, creating a new chain and the Geth client validators rejected them.

The situation worsened when validators running Teku, another Kintsugi client, also marked bad blocks as valid. As a consequence, this created a new fork.

The programmer commented on his Twitter that the creation of invalid blocks was kept for 2 days. He then said that, for now, the chain still had errors, which kept developers working to find them.

The error in question, which produced this great division, was caused intentionally. However, the results were not as expected. Although it was deliberately produced, such a scenario could take place on the ETH 2.0 mainnet.

In an interview, Marius van der Wijden said that such an error would be “very troublesome” on the mainnet.

“Although they are detectable errors, the levels of bifurcation caused can end up in the total failure of the network”, he said.

According to the programmer, these types of scenarios that took place on the testnet are a good sign. After all, they show developers’ response times to errors. In addition, it highlights that situations like this do not affect or delay the arrival of ETH 2.0.