diff --git a/list-objects.c b/list-objects.c
index bb7e61ef4b..b5651ddd5b 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -374,6 +374,9 @@ static void do_traverse(struct traversal_context *ctx)
 			struct tree *tree = get_commit_tree(commit);
 			tree->object.flags |= NOT_USER_GIVEN;
 			add_pending_tree(ctx->revs, tree);
+		} else if (commit->object.parsed) {
+			die(_("unable to load root tree for commit %s"),
+			      oid_to_hex(&commit->object.oid));
 		}
 		ctx->show_commit(commit, ctx->show_data);
 
diff --git a/t/t6102-rev-list-unexpected-objects.sh b/t/t6102-rev-list-unexpected-objects.sh
index 28ee1bcb07..28611c978e 100755
--- a/t/t6102-rev-list-unexpected-objects.sh
+++ b/t/t6102-rev-list-unexpected-objects.sh
@@ -67,8 +67,10 @@ test_expect_success 'traverse unexpected non-tree root (lone)' '
 	test_must_fail git rev-list --objects $broken_commit
 '
 
-test_expect_failure 'traverse unexpected non-tree root (seen)' '
-	test_must_fail git rev-list --objects $blob $broken_commit
+test_expect_success 'traverse unexpected non-tree root (seen)' '
+	test_must_fail git rev-list --objects $blob $broken_commit \
+		>output 2>&1 &&
+	test_i18ngrep "not a tree" output
 '
 
 test_expect_success 'setup unexpected non-commit tag' '