From 4a449d1d0b6167d0b1f29402a621b345a69a8dcf Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sat, 6 Jun 2020 13:04:01 +0200
Subject: [PATCH] App: [skip ci] throw an exception if the expression gives NaN

---
 src/App/Expression.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/App/Expression.cpp b/src/App/Expression.cpp
index b8c58d6d2c..b50a82fcd9 100644
--- a/src/App/Expression.cpp
+++ b/src/App/Expression.cpp
@@ -2301,7 +2301,12 @@ Py::Object FunctionExpression::evaluate(const Expression *expr, int f, const std
         _EXPR_THROW("Unknown function: " << f,expr);
     }
 
-    return Py::asObject(new QuantityPy(new Quantity(scaler * output, unit)));
+    Quantity q(scaler * output, unit);
+    if (!q.isValid()) {
+        throw Base::ValueError("Not a number");
+    }
+
+    return Py::asObject(new QuantityPy(new Quantity(q)));
 }
 
 Py::Object FunctionExpression::_getPyValue() const {