How to Bisect a Regression with Version Control

Bisecting finds the breaking change fast by binary search instead of checking every commit. Here is how to use it.

How to fix it

1. Mark a known-good and known-bad commit

Identify a commit where the bug is absent and one where it is present. Bisection searches between them, so accurate endpoints are the starting point.

2. Test the midpoint repeatedly

git bisect checks out the midpoint; test whether the bug is present and mark it good or bad. Each step halves the range, so even hundreds of commits resolve in a handful of tests.

3. Inspect the culprit commit

Bisection lands on the exact commit that introduced the regression. Review its diff — the cause is in that change, turning a search across all of history into reading one small commit.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.