What if you cannot test a commit during git bisect?
SHORT ANSWER
Run git bisect skip. Git moves to a nearby commit instead. If too many are skipped, it may only narrow the bug to a range of commits rather than one.
Explain it simply
Sometimes a middle commit does not even build because of an unrelated broken change. You can neither call it good nor bad, so you tell Git to try another.
git bisect skip removes that commit from consideration and picks a neighbour. If the bad commit hides among skipped ones, Git reports a list of candidates instead of one. In a scripted run, exit code 125 does the same.
Example
bash
git bisect start
git bisect bad
git bisect good v1.0
# the checked-out commit fails to compile
git bisect skipWhat to say in the interview
"git bisect skip tells Git I cannot judge this commit, and it tries a neighbour. With many skips it may return a range, not a single commit. In scripts, exit code 125 does the same job."