Teach builtin-notes to remove empty notes

diff --git a/sha1_name.c b/sha1_name.c
index ca8f9dba94e69bf625511443eb511aa63e04fd0a..1739e9e61240c33a1e2bf110bbeeee111c380716 100644 (file)
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -794,6 +794,48 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
        return retval;
 }
 
+int get_sha1_mb(const char *name, unsigned char *sha1)
+{
+       struct commit *one, *two;
+       struct commit_list *mbs;
+       unsigned char sha1_tmp[20];
+       const char *dots;
+       int st;
+
+       dots = strstr(name, "...");
+       if (!dots)
+               return get_sha1(name, sha1);
+       if (dots == name)
+               st = get_sha1("HEAD", sha1_tmp);
+       else {
+               struct strbuf sb;
+               strbuf_init(&sb, dots - name);
+               strbuf_add(&sb, name, dots - name);
+               st = get_sha1(sb.buf, sha1_tmp);
+               strbuf_release(&sb);
+       }
+       if (st)
+               return st;
+       one = lookup_commit_reference_gently(sha1_tmp, 0);
+       if (!one)
+               return -1;
+
+       if (get_sha1(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
+               return -1;
+       two = lookup_commit_reference_gently(sha1_tmp, 0);
+       if (!two)
+               return -1;
+       mbs = get_merge_bases(one, two, 1);
+       if (!mbs || mbs->next)
+               st = -1;
+       else {
+               st = 0;
+               hashcpy(sha1, mbs->item->object.sha1);
+       }
+       free_commit_list(mbs);
+       return st;
+}
+
 /*
  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
  * notably "xyz^" for "parent of xyz"