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136 lines
3.9 KiB
136 lines
3.9 KiB
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 |
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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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$ 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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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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$ git bisect good # this one is good |
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which will now say |
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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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$ git bisect reset |
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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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$ git bisect visualize |
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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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