Subject: Re: [PATCH v5 2/2] Add new @ shortcut for HEAD

From: Junio C Hamano <[email-masked]>
Date: Tue, 03 Sep 2013 11:50:49 -0700

Felipe Contreras <[email-masked]> writes:

> diff --git a/sha1_name.c b/sha1_name.c
> index 93197b9..b8ece6e 100644
> --- a/sha1_name.c
> +++ b/sha1_name.c
> @@ -1004,6 +1004,26 @@ int get_sha1_mb(const char *name, unsigned char *sha1)
>  	return st;
>  }
>  
> +/* parse @something syntax, when 'something' is not {.*} */
> +static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
> +{
> +	const char *next;
> +
> +	if (len || name[1] == '{')
> +		return -1;
> +
> +	/* make sure it's a single @, or @@{.*}, not @foo */
> +	next = strchr(name + len + 1, '@');
> +	if (!next)
> +		next = name + namelen;
> +	if (next != name + 1)
> +		return -1;
> +
> +	strbuf_reset(buf);
> +	strbuf_add(buf, "HEAD", 4);
> +	return 1;
> +}

Hmph, is the above sufficient?  I added a case that mimics Stefano's
original regression report (which is handled) and another that uses
doubled "@" for the same purpose of introducing a "funny" hierarchy,
and it appears that "checkout -b" chokes on it.

 t/t1508-at-combinations.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/t/t1508-at-combinations.sh b/t/t1508-at-combinations.sh
index 3a52375..ceb8449 100755
--- a/t/t1508-at-combinations.sh
+++ b/t/t1508-at-combinations.sh
@@ -32,6 +32,8 @@ test_expect_success 'setup' '
 	git checkout -b upstream-branch &&
 	test_commit upstream-one &&
 	test_commit upstream-two &&
+	git checkout -b @/at-test &&
+	git checkout -b @@/at-test &&
 	git checkout -b @at-test &&
 	git checkout -b old-branch &&
 	test_commit old-one &&
@@ -58,6 +60,8 @@ check "@{-1}@{u}" ref refs/heads/master
 check "@{-1}@{u}@{1}" commit master-one
 check "@" commit new-two
 check "@@{u}" ref refs/heads/upstream-branch
+check "@@/at-test" ref refs/heads/@@/at-test
+check "@/at-test" ref refs/heads/@/at-test
 check "@at-test" ref refs/heads/@at-test
 nonsense "@{u}@{-1}"
 nonsense "@{0}@{0}"