interpret_branch_name(): handle auto-namelen for @{-1}

The interpret_branch_name() function takes a ptr/len pair
for the name, but you can pass "0" for "namelen", which will
cause it to check the length with strlen().

However, before we do that auto-namelen magic, we call
interpret_nth_prior_checkout(), which gets fed the bogus
"0". This was broken by 8cd4249c4 (interpret_branch_name:
always respect "namelen" parameter, 2014-01-15).  Though to
be fair to that commit, it was broken in the _opposite_
direction before, where we would always treat "name" as a
string even if a length was passed.

You can see the bug with "git log -g @{-1}". That code path
always passes "0", and without this patch it cannot figure
out which branch's reflog to show.

We can fix it by a small reordering of the code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sha1_name.c b/sha1_name.c
index 73a915ff1b3278f08ef4f327a55fe61d238f720a..9b5d14b4bf52884d2c6042ddcc5236be57123f48 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1263,11 +1263,12 @@ int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 {
        char *at;
        const char *start;
-       int len = interpret_nth_prior_checkout(name, namelen, buf);
+       int len;
 
        if (!namelen)
                namelen = strlen(name);
 
+       len = interpret_nth_prior_checkout(name, namelen, buf);
        if (!len) {
                return len; /* syntax Ok, not enough switches */
        } else if (len > 0) {

diff --git a/t/t0100-previous.sh b/t/t0100-previous.sh
index e0a69402324fed3c2fd7ca9495f5735742766108..58c0b7e9b6d99a6ea8a507da89eb66f3c8780c31 100755 (executable)
--- a/t/t0100-previous.sh
+++ b/t/t0100-previous.sh
@@ -56,5 +56,13 @@ test_expect_success 'merge @{-100} before checking out that many branches yet' '
        test_must_fail git merge @{-100}
 '
 
+test_expect_success 'log -g @{-1}' '
+       git checkout -b last_branch &&
+       git checkout -b new_branch &&
+       echo "last_branch@{0}" >expect &&
+       git log -g --format=%gd @{-1} >actual &&
+       test_cmp expect actual
+'
+
 test_done