sha1_name: fix error message for @{<N>}, @{<date>}

Currently, when we try to resolve @{<N>} or @{<date>} when the reflog
doesn't go back far enough, we get errors like:

# on branch master
$ git show @{10000}
fatal: Log for '' only has 7 entries.

$ git show @{10000.days.ago}
warning: Log for '' only goes back to Tue, 21 May 2013 14:14:45 +0530.
...

# detached HEAD case
$ git show @{10000}
fatal: Log for '' only has 2005 entries.

$ git show master@{10000}
fatal: Log for 'master' only has 7 entries.

The empty string '' is confusing and does not convey information
about whose logs we are inspecting.  Change this so that we get:

# on branch master
$ git show @{10000}
fatal: Log for 'master' only has 7 entries.

$ git show @{10000.days.ago}
warning: Log for 'master' only goes back to Tue, 21 May 2013 14:14:45 +0530.
...

# detached HEAD case
$ git show @{10000}
fatal: Log for 'HEAD' only has 2005 entries.

$ git show master@{10000}
fatal: Log for 'master' only has 7 entries.

Also one of the message strings given to die() now points into
real_ref that was not used in that fashion, so stop freeing the
underlying storage for it.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Bug-spotted-and-fixed-by: Thomas Rast
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/sha1_name.c b/sha1_name.c
index 416a673d684129f0d515b4f1612cc97f7e74a55d..01b36ead42c2c7d22550c83061e8ff17b91720f6 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -517,12 +517,21 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
                }
                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
                                &co_time, &co_tz, &co_cnt)) {
+                       if (!len) {
+                               if (!prefixcmp(real_ref, "refs/heads/")) {
+                                       str = real_ref + 11;
+                                       len = strlen(real_ref + 11);
+                               } else {
+                                       /* detached HEAD */
+                                       str = "HEAD";
+                                       len = 4;
+                               }
+                       }
                        if (at_time)
                                warning("Log for '%.*s' only goes "
                                        "back to %s.", len, str,
                                        show_date(co_time, co_tz, DATE_RFC2822));
                        else {
-                               free(real_ref);
                                die("Log for '%.*s' only has %d entries.",
                                    len, str, co_cnt);
                        }