git rebase + fuzz = possible bad merge

From: Benny Halevy <bhalevy@panasas.com>
Date: Mar 23, 2009, 10:41 UTC
Message-ID: <49C7675E.9000309@panasas.com>

I'm hitting bad merges with (non interactive) git rebase when a hunk is merged pre-maturely into an inexact match when there's fuzz.

The following shell script reproduce this with git version 1.6.2.1:

#!/bin/sh

rm -rf test_file .git git init

cat >test_file <<EOF
struct one {
	line 1;
	line 2;
	line 3;
	line 4;
	line 5;
	line 6;
	line 7;
};

struct two {
	line 1;
	line 2;
	line 3;
	line 4;
	line 5;
	line 6;
	line 7;
};
EOF

git add test_file git commit -m test_file

git am <<EOF
From: Benny Halevy <bhalevy@panasas.com>
Subject: change struct two

diff --git a/test_file b/test_file
--- a/test_file
+++ b/test_file
@@ -12,7 +12,7 @@ struct two {
 	line 1;
 	line 2;
 	line 3;
-	line 4;
+	LINE 4;
 	line 5;
 	line 6;
 	line 7;
EOF

git checkout -b test_branch HEAD^
{ for i in {1..10}; do echo fuzz $i; done; echo; cat test_file; } > fuzz_file
mv fuzz_file test_file

git commit -a -m fuzz

git rebase --onto test_branch master^ master

if [ $(awk '/LINE/ {print NR}' test_file) != 26 ]; then
	echo 1>&2 $0: test failed
	exit 1
else
	echo 1>&2 $0: test succeeded
fi