checkout: don't crash on file checkout before running post-checkout hook

In the case of

	git init
	echo exit >.git/hooks/post-checkout
	chmod +x .git/hooks/post-checkout
	touch foo
	git add foo
	rm foo
	git checkout -- foo

git-checkout resulted in a Segmentation fault, because there is no new
branch set for the post-checkout hook.

This patch makes use of the null SHA as it is set for the old branch.

While at it, I removed the xstrdup() around the sha1_to_hex(...) calls
in builtin-checkout.c/post_checkout_hook() because sha1_to_hex()
uses four buffers for the hex-dumped SHA and we only need two.
(Duplicating one buffer is only needed if we need more than four.)

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Stephan Beyer 2009-01-16 20:09:58 +01:00 коммит произвёл Junio C Hamano
Родитель 7bbd8d6c13
Коммит 2292ce4785
1 изменённых файлов: 4 добавлений и 2 удалений

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@ -47,8 +47,10 @@ static int post_checkout_hook(struct commit *old, struct commit *new,
memset(&proc, 0, sizeof(proc)); memset(&proc, 0, sizeof(proc));
argv[0] = name; argv[0] = name;
argv[1] = xstrdup(sha1_to_hex(old ? old->object.sha1 : null_sha1)); argv[1] = sha1_to_hex(old ? old->object.sha1 : null_sha1);
argv[2] = xstrdup(sha1_to_hex(new->object.sha1)); argv[2] = sha1_to_hex(new ? new->object.sha1 : null_sha1);
/* "new" can be NULL when checking out from the index before
a commit exists. */
argv[3] = changed ? "1" : "0"; argv[3] = changed ? "1" : "0";
argv[4] = NULL; argv[4] = NULL;
proc.argv = argv; proc.argv = argv;