git-bisect.txt: example for bisecting with hot-fix

Give an example on how to bisect when older revisions need a hot-fix to
build, run or test. Triggered by the binutils/kernel issue at

http://thread.gmane.org/gmane.comp.gnu.binutils/52601/focus=1112779

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 47e8b1ed66087bf6d2e33969ea7ea2d32b620393..989e2238d653f2141a8cca061412f043ef13bcae 100644 (file)
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -294,6 +294,39 @@ 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.
 
 outside the repository to prevent interactions between the bisect,
 make and test processes and the scripts.
 

+* Automatically bisect with temporary modifications (hot-fix):
++
+------------
+$ cat ~/test.sh
+#!/bin/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
+------------
++
+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 case:
 +
 ------------
 * Automatically bisect a broken test case:
 +
 ------------