137 lines
3.9 KiB
Plaintext
137 lines
3.9 KiB
Plaintext
git-bisect(1)
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=============
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NAME
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----
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git-bisect - Find the change that introduced a bug by binary search
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SYNOPSIS
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--------
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'git bisect' <subcommand> <options>
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DESCRIPTION
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-----------
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The command takes various subcommands, and different options
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depending on the subcommand:
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git bisect start [<paths>...]
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git bisect bad <rev>
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git bisect good <rev>
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git bisect reset [<branch>]
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git bisect visualize
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git bisect replay <logfile>
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git bisect log
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This command uses 'git-rev-list --bisect' option to help drive
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the binary search process to find which change introduced a bug,
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given an old "good" commit object name and a later "bad" commit
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object name.
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The way you use it is:
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------------------------------------------------
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$ git bisect start
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$ git bisect bad # Current version is bad
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$ git bisect good v2.6.13-rc2 # v2.6.13-rc2 was the last version
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# tested that was good
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------------------------------------------------
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When you give at least one bad and one good versions, it will
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bisect the revision tree and say something like:
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------------------------------------------------
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Bisecting: 675 revisions left to test after this
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------------------------------------------------
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and check out the state in the middle. Now, compile that kernel, and boot
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it. Now, let's say that this booted kernel works fine, then just do
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------------------------------------------------
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$ git bisect good # this one is good
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------------------------------------------------
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which will now say
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------------------------------------------------
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Bisecting: 337 revisions left to test after this
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------------------------------------------------
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and you continue along, compiling that one, testing it, and depending on
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whether it is good or bad, you say "git bisect good" or "git bisect bad",
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and ask for the next bisection.
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Until you have no more left, and you'll have been left with the first bad
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kernel rev in "refs/bisect/bad".
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Oh, and then after you want to reset to the original head, do a
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------------------------------------------------
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$ git bisect reset
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------------------------------------------------
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to get back to the master branch, instead of being in one of the bisection
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branches ("git bisect start" will do that for you too, actually: it will
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reset the bisection state, and before it does that it checks that you're
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not using some old bisection branch).
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During the bisection process, you can say
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------------
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$ git bisect visualize
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------------
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to see the currently remaining suspects in `gitk`.
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The good/bad input is logged, and `git bisect
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log` shows what you have done so far. You can truncate its
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output somewhere and save it in a file, and run
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------------
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$ git bisect replay that-file
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------------
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if you find later you made a mistake telling good/bad about a
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revision.
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If in a middle of bisect session, you know what the bisect
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suggested to try next is not a good one to test (e.g. the change
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the commit introduces is known not to work in your environment
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and you know it does not have anything to do with the bug you
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are chasing), you may want to find a near-by commit and try that
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instead. It goes something like this:
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------------
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$ git bisect good/bad # previous round was good/bad.
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Bisecting: 337 revisions left to test after this
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$ git bisect visualize # oops, that is uninteresting.
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$ git reset --hard HEAD~3 # try 3 revs before what
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# was suggested
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------------
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Then compile and test the one you chose to try. After that,
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tell bisect what the result was as usual.
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You can further cut down the number of trials if you know what
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part of the tree is involved in the problem you are tracking
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down, by giving paths parameters when you say `bisect start`,
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like this:
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------------
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$ git bisect start arch/i386 include/asm-i386
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------------
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Author
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------
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Written by Linus Torvalds <torvalds@osdl.org>
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Documentation
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-------------
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Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
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GIT
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---
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Part of the gitlink:git[7] suite
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