The PoC v5 update exposed a few edge cases in blockchain-core related to Uber’s H3 library. The grid_distance function in H3 can crash in the following scenarios:

  • Pentagonal distortion
  • Mismatched h3 resolutions
  • Hotspots being too far away with no possible grid_distance existing between them


blockchain-core#325 addresses the above crashes. This fix attempts to calculate the distance and fails gracefully if any of the above scenarios occur.

Deployment Plan

On December 18 around 10:20 AM PDT we rolled out a 2019.12.18.0 beta release with a hotfix for these issues. We plan to let this beta run for 1 hour then deploy it to the network at large.