Linus says:
I'm testing bisection to find a bug that causes my G5 to no longer boot,
and during the process have found this command line very nice:
gitk bisect/bad --not $(cd .git/refs ; ls bisect/good-*)
it basically shows the state of bisection with the known bad commit as the
top, and cutting off all the good commits - so what you see are the
potential buggy commits.
Signed-off-by: Junio C Hamano <junkio@cox.net>
When testing bisection and using gitk to visualize the result, it was
obvious that the termination condition was broken.
We know what the bad entry is only when the bisection ends up telling us
to test the known-bad entry again.
Also, add a safety net: if somebody marks as good something that includes
the known-bad point, we now notice and complain, instead of writing an
empty revision to the new bisection branch.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
When I munged the original from Linus, which did not terminate
when the last bisect to check happened to be a bad one, to
terminate, I seem to have botched the end result to pick.
Thanks for Sanjoy Mahajan for a good reproduction recipe to
diagnose this.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This adds a new "git bisect" command.
- "git bisect start"
start bisection search.
- "git bisect bad <rev>"
mark some version known-bad (if no arguments, then current HEAD)
- "git bisect good <revs>..."
mark some versions known-good (if no arguments, then current HEAD)
- "git bisect reset <branch>"
done with bisection search and go back to your work (if
no arguments, then "master").
The way you use it is:
git bisect start
git bisect bad # Current version is bad
git bisect good v2.6.13-rc2 # v2.6.13-rc2 was the last version
# tested that was good
When you give at least one bad and one good versions, it will
bisect the revision tree and say something like:
Bisecting: 675 revisions left to test after this
and check out the state in the middle. Now, compile that kernel, and boot
it. Now, let's say that this booted kernel works fine, then just do
git bisect good # this one is good
which will now say
Bisecting: 337 revisions left to test after this
and you continue along, compiling that one, testing it, and depending on
whether it is good or bad, you say "git bisect good" or "git bisect bad",
and ask for the next bisection.
Until you have no more left, and you'll have been left with the first bad
kernel rev in "refs/bisect/bad".
Oh, and then after you want to reset to the original head, do a
git bisect reset
to get back to the master branch, instead of being in one of the bisection
branches ("git bisect start" will do that for you too, actually: it will
reset the bisection state, and before it does that it checks that you're
not using some old bisection branch).
Not really any harder than doing series of "quilt push" and "quilt pop",
now is it?
[jc: This patch is a rework based on what Linus posted to the
list. The changes are:
- The original introduced four separate commands, which was
three too many, so I merged them into one with subcommands.
- Since the next thing you would want to do after telling it
"bad" and "good" is always to bisect, this version does it
automatically for you.
- I think the termination condition was wrong. The original
version checked if the set of revisions reachable from next
bisection but not rechable from any of the known good ones
is empty, but if the current bisection was a bad one, this
would not terminate, so I changed it to terminate it when
the set becomes a singleton or empty.
- Removed the use of shell array variable.
]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
