Bisect is a debugging technique used to identify which specific code change (commit) introduced a regression in libWebRTC or Chrome.
How bisecting works for WebRTC
When a WebRTC bug is discovered in a new Chrome version:
- A known-good version and a known-bad version are identified
- The midpoint between them is tested
- Based on whether the bug is present, the search range is halved
- This binary search continues until the exact commit that introduced the bug is found
Google provides pre-built Chrome snapshots that make bisecting feasible without building Chrome from source. The Chromium project's bisect tools automate much of this process.
Why bisecting matters
libWebRTC receives hundreds of commits between Chrome releases. When a WebRTC regression is found, bisecting is often the fastest way to identify the root cause. Developers can then file targeted bugs against the specific change, significantly accelerating the fix process.
This is closely related to Field Trials and Finch experiments, which provide another way to identify problematic changes by toggling features on and off.
