From df15d256d5177839a6c43eb5f173b401b9e06dd9 Mon Sep 17 00:00:00 2001
From: John Bytheway <jbytheway@gmail.com>
Date: Fri, 24 Jan 2020 22:22:30 -0500
Subject: [PATCH] Avoid crafting_success_roll returning NaN

The crafting_success_roll could end up computing 0.0/0.0.  This happened
to work, but more by luck than design, so check for that case
explicitly.

(NaN values are unsafe given that we're compiling with -ffast-math).
---
 src/crafting.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/crafting.cpp b/src/crafting.cpp
index 00869459eb0c3..7cec55fba8e1a 100644
--- a/src/crafting.cpp
+++ b/src/crafting.cpp
@@ -908,6 +908,11 @@ double player::crafting_success_roll( const recipe &making ) const
     const double skill_roll = dice( skill_dice, skill_sides );
     const double diff_roll = dice( diff_dice, diff_sides );
 
+    if( diff_roll == 0 ) {
+        // Automatic success
+        return 2;
+    }
+
     return skill_roll / diff_roll;
 }