diff options
Diffstat (limited to 'Documentation/git-bisect.txt')
| -rw-r--r-- | Documentation/git-bisect.txt | 102 |
1 files changed, 65 insertions, 37 deletions
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt index 63e7a42cb3..7b7bafba0c 100644 --- a/Documentation/git-bisect.txt +++ b/Documentation/git-bisect.txt @@ -20,7 +20,7 @@ on the subcommand: git bisect bad [<rev>] git bisect good [<rev>...] git bisect skip [(<rev>|<range>)...] - git bisect reset [<branch>] + git bisect reset [<commit>] git bisect visualize git bisect replay <logfile> git bisect log @@ -81,16 +81,27 @@ will have been left with the first bad kernel revision in "refs/bisect/bad". Bisect reset ~~~~~~~~~~~~ -To return to the original head after a bisect session, issue the -following command: +After a bisect session, to clean up the bisection state and return to +the original HEAD, issue the following command: ------------------------------------------------ $ git bisect reset ------------------------------------------------ -This resets the tree to the original branch instead of being on the -bisection commit ("git bisect start" will also do that, as it resets -the bisection state). +By default, this will return your tree to the commit that was checked +out before `git bisect start`. (A new `git bisect start` will also do +that, as it cleans up the old bisection state.) + +With an optional argument, you can return to a different commit +instead: + +------------------------------------------------ +$ git bisect reset <commit> +------------------------------------------------ + +For example, `git bisect reset HEAD` will leave you on the current +bisection commit and avoid switching commits at all, while `git bisect +reset bisect/bad` will check out the first bad revision. Bisect visualize ~~~~~~~~~~~~~~~~ @@ -230,7 +241,12 @@ exit(3) manual page), as the value is chopped with "& 0377". The special exit code 125 should be used when the current source code cannot be tested. If the script exits with this code, the current -revision will be skipped (see `git bisect skip` above). +revision will be skipped (see `git bisect skip` above). 125 was chosen +as the highest sensible value to use for this purpose, because 126 and 127 +are used by POSIX shells to signal specific error status (127 is for +command not found, 126 is for command found but not executable---these +details do not matter, as they are normal errors in the script, as far as +"bisect run" is concerned). You may often find that during a bisect session you want to have temporary modifications (e.g. s/#define DEBUG 0/#define DEBUG 1/ in a @@ -263,61 +279,73 @@ $ git bisect start HEAD origin -- # HEAD is bad, origin is good $ git bisect run make test # "make test" builds and tests ------------ -* Automatically bisect a broken test suite: +* Automatically bisect a broken test case: + ------------ $ cat ~/test.sh #!/bin/sh -make || exit 125 # this skips broken builds -make test # "make test" runs the test suite -$ git bisect start v1.3 v1.1 -- # v1.3 is bad, v1.1 is good +make || exit 125 # this skips broken builds +~/check_test_case.sh # does the test case pass? +$ git bisect start HEAD HEAD~10 -- # culprit is among the last 10 $ git bisect run ~/test.sh ------------ + Here we use a "test.sh" custom script. In this script, if "make" fails, we skip the current commit. +"check_test_case.sh" should "exit 0" if the test case passes, +and "exit 1" otherwise. + -It is safer to use a custom script outside the repository to prevent -interactions between the bisect, make and test processes and the -script. -+ -"make test" should "exit 0", if the test suite passes, and -"exit 1" otherwise. +It is safer if both "test.sh" and "check_test_case.sh" are +outside the repository to prevent interactions between the bisect, +make and test processes and the scripts. -* Automatically bisect a broken test case: +* Automatically bisect with temporary modifications (hot-fix): + ------------ $ cat ~/test.sh #!/bin/sh -make || exit 125 # this skips broken builds -~/check_test_case.sh # does the test case passes ? -$ git bisect start HEAD HEAD~10 -- # culprit is among the last 10 -$ git bisect run ~/test.sh + +# tweak the working tree by merging the hot-fix branch +# and then attempt a build +if git merge --no-commit hot-fix && + make +then + # run project specific test and report its status + ~/check_test_case.sh + status=$? +else + # tell the caller this is untestable + status=125 +fi + +# undo the tweak to allow clean flipping to the next commit +git reset --hard + +# return control +exit $status ------------ + -Here "check_test_case.sh" should "exit 0" if the test case passes, -and "exit 1" otherwise. -+ -It is safer if both "test.sh" and "check_test_case.sh" scripts are -outside the repository to prevent interactions between the bisect, -make and test processes and the scripts. +This applies modifications from a hot-fix branch before each test run, +e.g. in case your build or test environment changed so that older +revisions may need a fix which newer ones have already. (Make sure the +hot-fix branch is based off a commit which is contained in all revisions +which you are bisecting, so that the merge does not pull in too much, or +use `git cherry-pick` instead of `git merge`.) -* Automatically bisect a broken test suite: +* Automatically bisect a broken test case: + ------------ $ git bisect start HEAD HEAD~10 -- # culprit is among the last 10 $ git bisect run sh -c "make || exit 125; ~/check_test_case.sh" ------------ + -Does the same as the previous example, but on a single line. - -Author ------- -Written by Linus Torvalds <torvalds@osdl.org> +This shows that you can do without a run script if you write the test +on a single line. -Documentation -------------- -Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. +SEE ALSO +-------- +link:git-bisect-lk2009.html[Fighting regressions with git bisect], +linkgit:git-blame[1]. GIT --- |