[PATCH] sha1_file: do not add own object directory as alternate

[Ephrim Khong <dr.khong@gmail.com>]

When adding alternate object directories, we try not to add the
directory of the current repository to avoid cycles.  Unfortunately,
that test was broken, since it compared an absolute with a relative
path.

Signed-off-by: Ephrim Khong <dr.khong@gmail.com>
---
My first patch, so be harsh.  I'm not sure about the filename of the 
test, the behavior is tested with repack, but it affects gc and others 
as well.

  sha1_file.c                        |  2 +-
  t/t7702-repack-cyclic-alternate.sh | 24 ++++++++++++++++++++++++
  2 files changed, 25 insertions(+), 1 deletion(-)
  create mode 100755 t/t7702-repack-cyclic-alternate.sh

diff --git a/sha1_file.c b/sha1_file.c
index 34d527f..7e98e9e 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -320,7 +320,7 @@ static int link_alt_odb_entry(const char *entry, 
const char *relative_base, int
  			return -1;
  		}
  	}
-	if (!strcmp(ent->base, objdir)) {
+	if (!strcmp(ent->base, absolute_path(objdir))) {
  		free(ent);
  		return -1;
  	}
diff --git a/t/t7702-repack-cyclic-alternate.sh 
b/t/t7702-repack-cyclic-alternate.sh
new file mode 100755
index 0000000..9a22d98
--- /dev/null
+++ b/t/t7702-repack-cyclic-alternate.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# Copyright (c) 2014 Ephrim Khong
+#
+
+test_description='repack involving cyclic alternate'
+. ./test-lib.sh
+
+test_expect_success setup '
+	git init repo &&
+	cd repo &&
+	touch a &&
+	git add a &&
+	git commit -m 1 &&
+	git repack -adl &&
+	echo $PWD/.git/objects > .git/objects/info/alternates
+'
+
+test_expect_success 're-packing repository with itsself as alternate' '
+	git repack -adl &&
+	git fsck
+'
+
+test_done
-- 
1.8.4.3