From e7bc9ba23c896f758c3a4139133cd58eb2b9c1f9 Mon Sep 17 00:00:00 2001
From: Youssef Badr <104090877+ybadr16@users.noreply.github.com>
Date: Fri, 16 Aug 2024 00:56:22 +0300
Subject: [PATCH] Added error if cross sections path is a folder (#3115)

---
 src/cross_sections.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/cross_sections.cpp b/src/cross_sections.cpp
index a7bd86095b..248ae9019d 100644
--- a/src/cross_sections.cpp
+++ b/src/cross_sections.cpp
@@ -283,6 +283,10 @@ void read_ce_cross_sections_xml()
 {
   // Check if cross_sections.xml exists
   const auto& filename = settings::path_cross_sections;
+  if (dir_exists(filename)) {
+    fatal_error("OPENMC_CROSS_SECTIONS is set to a directory. "
+                "It should be set to an XML file.");
+  }
   if (!file_exists(filename)) {
     // Could not find cross_sections.xml file
     fatal_error("Cross sections XML file '" + filename + "' does not exist.");