rev-parse: check lookup'ed commit references for NULL

diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 74aa644cbb37b5741c521eba53d0a040aaf1582e..da5748bdaef376f35fdb49125e959474913c6ad9 100644 (file)
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -282,6 +282,10 @@ static int try_difference(const char *arg)
                        struct commit *a, *b;
                        a = lookup_commit_reference(&oid);
                        b = lookup_commit_reference(&end);
+                       if (!a || !b) {
+                               *dotdot = '.';
+                               return 0;
+                       }
                        exclude = get_merge_bases(a, b);
                        while (exclude) {
                                struct commit *commit = pop_commit(&exclude);
@@ -328,12 +332,12 @@ static int try_parent_shorthands(const char *arg)
                return 0;
 
        *dotdot = 0;
-       if (get_oid_committish(arg, &oid)) {
+       if (get_oid_committish(arg, &oid) ||
+           !(commit = lookup_commit_reference(&oid))) {
                *dotdot = '^';
                return 0;
        }
 
-       commit = lookup_commit_reference(&oid);
        if (exclude_parent &&
            exclude_parent > commit_list_count(commit->parents)) {
                *dotdot = '^';