sha1_name: check @{-N} errors sooner

It's trivial to check for them in the @{N} parsing loop.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sha1_name.c b/sha1_name.c
index 45b89d9df00de3c31a39a74a0cc0e635b0095cbc..446cc62c4ecfced70dd480674aef370e0f860141 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -448,7 +448,10 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
        if (len && str[len-1] == '}') {
                for (at = len-4; at >= 0; at--) {
                        if (str[at] == '@' && str[at+1] == '{') {
-                               if (at == 0 && str[2] == '-') {
+                               if (str[at+2] == '-') {
+                                       if (at != 0)
+                                               /* @{-N} not at start */
+                                               return -1;
                                        nth_prior = 1;
                                        continue;
                                }
@@ -497,10 +500,6 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
                unsigned long co_time;
                int co_tz, co_cnt;
 
-               /* a @{-N} placed anywhere except the start is an error */
-               if (str[at+2] == '-')
-                       return -1;
-
                /* Is it asking for N-th entry, or approxidate? */
                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
                        char ch = str[at+2+i];