velith / locate-error

Git bisect exercise.

Git bisect exercise

The script get_pi.py calculates pi using the 100 first terms of the Nilakantha series. It should produce 3.141592 but it does not. It produces 3.264592 using the last commit. At each commit, the 100 terms are reshuffled. At some point within the 1000 first commits, an error was introduced. The only thing we know is that the first commit worked correctly.

Use git bisect to find the commit which broke the computation.

Bonus: write a script that checks for a correct result and use git bisect run to find the offending commit automatically.

The motivation for this exercise is to be able to do archaeology with Git on a source code where the bug is difficult to see visually. Finding the offending commit is often more than half the debugging. In this particular example the knowledge about the offending commit will not help us but in reality mastering git bisect is a huge time saver.