SYNOPSIS
--------
-'git bisect' <subcommand> <options>
+'git bisect' <subcommand> <options>
DESCRIPTION
-----------
The command takes various subcommands, and different options depending
on the subcommand:
+ git bisect help
git bisect start [<bad> [<good>...]] [--] [<paths>...]
- git bisect bad <rev>
- git bisect good <rev>
+ git bisect bad [<rev>]
+ git bisect good [<rev>...]
+ git bisect skip [<rev>...]
git bisect reset [<branch>]
git bisect visualize
git bisect replay <logfile>
git bisect log
git bisect run <cmd>...
-This command uses 'git-rev-list --bisect' option to help drive the
+This command uses 'git-rev-list --bisect' to help drive the
binary search process to find which change introduced a bug, given an
old "good" commit object name and a later "bad" commit object name.
+Getting help
+~~~~~~~~~~~~
+
+Use "git bisect" to get a short usage description, and "git bisect
+help" or "git bisect -h" to get a long usage description.
+
Basic bisect commands: start, bad, good
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ 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).
+to get back to the original branch, instead of being on the bisection
+commit ("git bisect start" will do that for you too, actually: it will
+reset the bisection state).
Bisect visualize
~~~~~~~~~~~~~~~~
$ git bisect visualize
------------
-to see the currently remaining suspects in `gitk`.
+to see the currently remaining suspects in 'gitk'. `visualize` is a bit
+too long to type and `view` is provided as a synonym.
+
+If 'DISPLAY' environment variable is not set, 'git-log' is used
+instead. You can even give command line options such as `-p` and
+`--stat`.
+
+------------
+$ git bisect view --stat
+------------
Bisect log and bisect replay
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Then compile and test the one you chose to try. After that, tell
bisect what the result was as usual.
+Bisect skip
+~~~~~~~~~~~~
+
+Instead of choosing by yourself a nearby commit, you may just want git
+to do it for you using:
+
+------------
+$ git bisect skip # Current version cannot be tested
+------------
+
+But computing the commit to test may be slower afterwards and git may
+eventually not be able to tell the first bad among a bad and one or
+more "skip"ped commits.
+
Cutting down bisection by giving more parameters to bisect start
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
------------
Note that the "run" script (`my_script` in the above example) should
-exit with code 0 in case the current source code is good and with a
-code between 1 and 127 (included) in case the current source code is
-bad.
+exit with code 0 in case the current source code is good. Exit with a
+code between 1 and 127 (inclusive), except 125, if the current
+source code is bad.
Any other exit code will abort the automatic bisect process. (A
program that does "exit(-1)" leaves $? = 255, see exit(3) manual page,
the value is chopped with "& 0377".)
+The special exit code 125 should be used when the current source code
+cannot be tested. If the "run" script exits with this code, the current
+revision will be skipped, see `git bisect skip` above.
+
You may often find that during bisect you want to have near-constant
tweaks (e.g., s/#define DEBUG 0/#define DEBUG 1/ in a header file, or
"revision that does not have this commit needs this patch applied to
work around other problem this bisection is not interested in")
applied to the revision being tested.
-To cope with such a situation, after the inner git-bisect finds the
+To cope with such a situation, after the inner 'git-bisect' finds the
next revision to test, with the "run" script, you can apply that tweak
before compiling, run the real test, and after the test decides if the
revision (possibly with the needed tweaks) passed the test, rewind the
tree to the pristine state. Finally the "run" script can exit with
-the status of the real test to let "git bisect run" command loop to
-know the outcome.
+the status of the real test to let the "git bisect run" command loop to
+determine the outcome.
+
+EXAMPLES
+--------
+
+* Automatically bisect a broken build between v1.2 and HEAD:
++
+------------
+$ git bisect start HEAD v1.2 -- # HEAD is bad, v1.2 is good
+$ git bisect run make # "make" builds the app
+------------
+
+* Automatically bisect a broken test suite:
++
+------------
+$ cat ~/test.sh
+#!/bin/sh
+make || exit 125 # this "skip"s 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
+$ git bisect run ~/test.sh
+------------
++
+Here we use a "test.sh" custom script. In this script, if "make"
+fails, we "skip" the current commit.
++
+It's safer to use a custom script outside the repo to prevent
+interactions between the bisect, make and test processes and the
+script.
++
+And "make test" should "exit 0", if the test suite passes, and
+"exit 1" (for example) otherwise.
+
+* Automatically bisect a broken test case:
++
+------------
+$ cat ~/test.sh
+#!/bin/sh
+make || exit 125 # this "skip"s 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
+------------
++
+Here "check_test_case.sh" should "exit 0", if the test case passes,
+and "exit 1" (for example) otherwise.
++
+It's safer if both "test.sh" and "check_test_case.sh" scripts are
+outside the repo to prevent interactions between the bisect, make and
+test processes and the scripts.
Author
------
GIT
---
-Part of the gitlink:git[7] suite
-
+Part of the linkgit:git[1] suite