From 64d662f92e079bd77a514cd7fe380cd3443577fc Mon Sep 17 00:00:00 2001
From: j-lojek <208155505+j-lojek@users.noreply.github.com>
Date: Fri, 20 Feb 2026 19:34:33 +0100
Subject: [PATCH] nle: guard empty hackdir before suffix normalization

---
 src/nle.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/nle.c b/src/nle.c
index 07f315083..d257b0a83 100644
--- a/src/nle.c
+++ b/src/nle.c
@@ -183,7 +183,12 @@ mainloop(fcontext_transfer_t ctx_transfer)
                                 stack->ssize);
 #endif
 
-    int len = strnlen(settings.hackdir, sizeof(settings.hackdir));
+    size_t len = strnlen(settings.hackdir, sizeof(settings.hackdir));
+
+    if (len == 0) {
+        error("HACKDIR must not be empty");
+        return;
+    }
 
     if (len >= sizeof(settings.hackdir) - 1) {
         error("HACKDIR too long");