From c4ca0d45cb66ad5b038f4eb776d09623c2c1e7b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophane=20Hufschmitt?=
 <theophane.hufschmitt@tweag.io>
Date: Mon, 26 Jun 2023 09:01:06 +0200
Subject: [PATCH] nix-find-roots: Don't assume that `argv[0]` exists

---
 src/nix-find-roots/main.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/nix-find-roots/main.cc b/src/nix-find-roots/main.cc
index 6de5efa69..0e8aabb91 100644
--- a/src/nix-find-roots/main.cc
+++ b/src/nix-find-roots/main.cc
@@ -23,7 +23,8 @@ TracerConfig parseCmdLine(int argc, char** argv)
     fs::path socketPath = "/nix/var/nix/gc-trace-socket/socket";
 
     auto usage = [&]() {
-        std::cerr << "Usage: " << string(argv[0]) << " [--verbose|-v] [-s storeDir] [-d stateDir] [-l socketPath]" << std::endl;
+        std::string programName = argc > 0 ? argv[0] : "nix-find-roots";
+        std::cerr << "Usage: " << programName << " [--verbose|-v] [-s storeDir] [-d stateDir] [-l socketPath]" << std::endl;
         exit(1);
     };
     static struct option long_options[] = {