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* dm/maint-docco:
  Documentation: reword example text in git-bisect.txt.
  Documentation: reworded the "Description" section of git-bisect.txt.
  Documentation: minor grammatical fixes in git-branch.txt.
  Documentation: minor grammatical fixes in git-blame.txt.
  Documentation: reword the "Description" section of git-bisect.txt.
  Documentation: minor grammatical fixes in git-archive.txt.
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Junio C Hamano committed Mar 22, 2009
2 parents d291a9a + 4306bcb commit 88f78ce
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2 changes: 1 addition & 1 deletion Documentation/blame-options.txt
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@ of lines before or after the line given by <start>.
Show raw timestamp (Default: off).

-S <revs-file>::
Use revs from revs-file instead of calling linkgit:git-rev-list[1].
Use revisions from revs-file instead of calling linkgit:git-rev-list[1].

--reverse::
Walk history forward instead of backward. Instead of showing
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8 changes: 4 additions & 4 deletions Documentation/git-archive.txt
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ prepended to the filenames in the archive.

'git-archive' behaves differently when given a tree ID versus when
given a commit ID or tag ID. In the first case the current time is
used as modification time of each file in the archive. In the latter
used as the modification time of each file in the archive. In the latter
case the commit time as recorded in the referenced commit object is
used instead. Additionally the commit ID is stored in a global
extended pax header if the tar format is used; it can be extracted
Expand Down Expand Up @@ -52,11 +52,11 @@ OPTIONS
Write the archive to <file> instead of stdout.

<extra>::
This can be any options that the archiver backend understand.
This can be any options that the archiver backend understands.
See next section.

--remote=<repo>::
Instead of making a tar archive from local repository,
Instead of making a tar archive from the local repository,
retrieve a tar archive from a remote repository.

--exec=<git-upload-archive>::
Expand Down Expand Up @@ -109,7 +109,7 @@ EXAMPLES
git archive --format=tar --prefix=junk/ HEAD | (cd /var/tmp/ && tar xf -)::

Create a tar archive that contains the contents of the
latest commit on the current branch, and extracts it in
latest commit on the current branch, and extract it in the
`/var/tmp/junk` directory.

git archive --format=tar --prefix=git-1.4.0/ v1.4.0 | gzip >git-1.4.0.tar.gz::
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171 changes: 88 additions & 83 deletions Documentation/git-bisect.txt
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ git-bisect(1)

NAME
----
git-bisect - Find the change that introduced a bug by binary search
git-bisect - Find by binary search the change that introduced a bug


SYNOPSIS
Expand Down Expand Up @@ -39,7 +39,8 @@ help" or "git bisect -h" to get a long usage description.
Basic bisect commands: start, bad, good
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The way you use it is:
Using the Linux kernel tree as an example, basic use of the bisect
command is as follows:

------------------------------------------------
$ git bisect start
Expand All @@ -48,61 +49,63 @@ $ 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:
When you have specified at least one bad and one good version, the
command bisects the revision tree and outputs something similar to
the following:

------------------------------------------------
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
The state in the middle of the set of revisions is then checked out.
You would now compile that kernel and boot it. If the booted kernel
works correctly, you would then issue the following command:

------------------------------------------------
$ git bisect good # this one is good
------------------------------------------------

which will now say
The output of this command would be something similar to the following:

------------------------------------------------
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.
You keep repeating this process, compiling the tree, testing it, and
depending on whether it is good or bad issuing the command "git bisect good"
or "git bisect bad" to 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".
Eventually there will be no more revisions left to bisect, and you
will have been left with the first bad kernel revision in "refs/bisect/bad".

Bisect reset
~~~~~~~~~~~~

Oh, and then after you want to reset to the original head, do a
To return to the original head after a bisect session, you issue the
following command:

------------------------------------------------
$ git bisect reset
------------------------------------------------

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).
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).

Bisect visualize
~~~~~~~~~~~~~~~~

During the bisection process, you can say
To see the currently remaining suspects in 'gitk', the following command
is issued during the bisection process:

------------
$ git bisect visualize
------------

to see the currently remaining suspects in 'gitk'. `visualize` is a bit
too long to type and `view` is provided as a synonym.
`view` may also be used as a synonym for `visualize`.

If 'DISPLAY' environment variable is not set, 'git log' is used
instead. You can even give command line options such as `-p` and
If the 'DISPLAY' environment variable is not set, 'git log' is used
instead. You can also give command line options such as `-p` and
`--stat`.

------------
Expand All @@ -112,57 +115,58 @@ $ git bisect view --stat
Bisect log and bisect replay
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The good/bad input is logged, and
After having marked revisions as good or bad, you issue the following
command to show what has been done so far:

------------
$ git bisect log
------------

shows what you have done so far. You can truncate its output somewhere
and save it in a file, and run
If you discover that you made a mistake in specifying the status of a
revision, you can save the output of this command to a file, edit it to
remove the incorrect entries, and then issue the following commands to
return to a corrected state:

------------
$ git bisect reset
$ git bisect replay that-file
------------

if you find later you made a mistake telling good/bad about a
revision.

Avoiding to test a commit
Avoiding testing a commit
~~~~~~~~~~~~~~~~~~~~~~~~~

If in a middle of bisect session, you know what the bisect suggested
to try next is not a good one to test (e.g. the change the commit
If in the middle of a bisect session, you know that the next suggested
revision is not a good one to test (e.g. the change the commit
introduces is known not to work in your environment and you know it
does not have anything to do with the bug you are chasing), you may
want to find a near-by commit and try that instead.
want to find a nearby commit and try that instead.

It goes something like this:
For example:

------------
$ git bisect good/bad # previous round was good/bad.
$ git bisect good/bad # previous round was good or bad.
Bisecting: 337 revisions left to test after this
$ git bisect visualize # oops, that is uninteresting.
$ git reset --hard HEAD~3 # try 3 revs before what
$ git reset --hard HEAD~3 # try 3 revisions before what
# was suggested
------------

Then compile and test the one you chose to try. After that, tell
bisect what the result was as usual.
Then compile and test the chosen revision. Afterwards the revision
is marked as good or bad in the usual manner.

Bisect skip
~~~~~~~~~~~~

Instead of choosing by yourself a nearby commit, you may just want git
to do it for you using:
Instead of choosing by yourself a nearby commit, you can ask git
to do it for you by issuing the command:

------------
$ 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.
eventually not be able to tell the first bad commit among a bad commit
and one or more skipped commits.

You can even skip a range of commits, instead of just one commit,
using the "'<commit1>'..'<commit2>'" notation. For example:
Expand All @@ -171,33 +175,34 @@ using the "'<commit1>'..'<commit2>'" notation. For example:
$ git bisect skip v2.5..v2.6
------------

would mean that no commit between `v2.5` excluded and `v2.6` included
can be tested.
The effect of this would be that no commit between `v2.5` excluded and
`v2.6` included could be tested.

Note that if you want to also skip the first commit of a range you can
use something like:
Note that if you also want to skip the first commit of the range you
would issue the command:

------------
$ git bisect skip v2.5 v2.5..v2.6
------------

and the commit pointed to by `v2.5` will be skipped too.
This would cause the commits between `v2.5` included and `v2.6` included
to be skipped.


Cutting down bisection by giving more parameters to bisect start
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can further cut down the number of trials if you know what part of
the tree is involved in the problem you are tracking down, by giving
paths parameters when you say `bisect start`, like this:
You can further cut down the number of trials, if you know what part of
the tree is involved in the problem you are tracking down, by specifying
path parameters when issuing the `bisect start` command:

------------
$ git bisect start -- arch/i386 include/asm-i386
------------

If you know beforehand more than one good commits, you can narrow the
bisect space down without doing the whole tree checkout every time you
give good commits. You give the bad revision immediately after `start`
and then you give all the good revisions you have:
If you know beforehand more than one good commit, you can narrow the
bisect space down by specifying all of the good commits immediately after
the bad commit when issuing the `bisect start` command:

------------
$ git bisect start v2.6.20-rc6 v2.6.20-rc4 v2.6.20-rc1 --
Expand All @@ -209,38 +214,38 @@ Bisect run
~~~~~~~~~~

If you have a script that can tell if the current source code is good
or bad, you can automatically bisect using:
or bad, you can bisect by issuing the command:

------------
$ git bisect run my_script arguments
------------

Note that the "run" script (`my_script` in the above example) should
exit with code 0 in case the current source code is good. Exit with a
Note that the script (`my_script` in the above example) should
exit with code 0 if the current source code is good, and 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".)
Any other exit code will abort the bisect process. It should be noted
that a program that terminates via "exit(-1)" leaves $? = 255, (see the
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 "run" script exits with this code, the current
revision will be skipped, see `git bisect skip` above.
cannot be tested. If the 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.
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
header file, or "revision that does not have this commit needs this
patch applied to work around another 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
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 the "git bisect run" command loop to
determine the outcome.
next revision to test, the script can apply the patch
before compiling, run the real test, and afterwards decide if the
revision (possibly with the needed patch) passed the test and then
rewind the tree to the pristine state. Finally the script should exit
with the status of the real test to let the "git bisect run" command loop
determine the eventual outcome of the bisect session.

EXAMPLES
--------
Expand All @@ -264,39 +269,39 @@ $ git bisect run make test # "make test" builds and tests
------------
$ cat ~/test.sh
#!/bin/sh
make || exit 125 # this "skip"s broken builds
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
$ git bisect run ~/test.sh
------------
+
Here we use a "test.sh" custom script. In this script, if "make"
fails, we "skip" the current commit.
fails, we skip the current commit.
+
It's safer to use a custom script outside the repo to prevent
It is safer to use a custom script outside the repository 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.
"make test" should "exit 0", if the test suite passes, and
"exit 1" otherwise.

* Automatically bisect a broken test case:
+
------------
$ cat ~/test.sh
#!/bin/sh
make || exit 125 # this "skip"s broken builds
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
------------
+
Here "check_test_case.sh" should "exit 0", if the test case passes,
and "exit 1" (for example) otherwise.
Here "check_test_case.sh" should "exit 0" if the test case passes,
and "exit 1" 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.
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.

* Automatically bisect a broken test suite:
+
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