From: Michael Gofron <gofronm@yahoo.com>
Date: Fri, 21 Jun 2024 03:51:11 GMT
Subject: Git bisect skip
Message-ID: <968676664.8436621.1718941871973@mail.yahoo.com>
In-Reply-To: <968676664.8436621.1718941871973.ref@mail.yahoo.com>

Hello,

My question is can using `git bisect skip` cause a bisect to be indeterminate and/or fail if the commits that are skipped couldn't have caused the issue? 

Consider if my commits are like this:

1P - 2P - 3B - 4P - 5P - 6B - 7B - 8F - 9F. 
P for "Pass", B for "Broken", and F for "Fail". 
Broken commits are commits that we can't create a build for but wouldn't cause the issue.
Failing commits are failing because of a bug. 

In this case, 8F caused the bug.
If you tell git bisect that 1P is good and 9F is bad, bisect picks a commit between the known newest Good commit (1P) and the known oldest Bad commit (9F).

1P -- 2P - 3B - 4P - 5P - 6B - 7B - 8F - 9F
G                                        B
      <------------------------------>
Perhaps 4P. That builds and passes, so it marks that as Good.

If it then goes to 6B which is a Broken commit and we do `git bisect skip` what happens next? It seems from the code it uses a psuedo random number generator with bias to determine the next commit. Would it ever get in a state where it can't determine the commit that caused the issue even if these broken commits would never cause an issue? 

-Thank you
Michael Gofron