From e50cc3a0bd6daa57528e87940c0fc3e1ecac284d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89milie=20Feral?= <emilie.feral@numworks.com>
Date: Tue, 5 Jun 2018 09:53:24 +0200
Subject: [PATCH] [poincare] Avoid infinite loop in intersection/extrema solver

---
 poincare/src/expression.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index 4b9805361..e761e2532 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -491,8 +491,11 @@ Expression::Coordinate2D Expression::nextIntersection(char symbol, double start,
 }
 
 Expression::Coordinate2D Expression::nextMinimumOfExpression(char symbol, double start, double step, double max, EvaluationAtAbscissa evaluate, Context & context, const Expression * expression, bool lookForRootMinimum) const {
-  double bracket[3];
   Coordinate2D result = {.abscissa = NAN, .value = NAN};
+  if (start == max || step == 0.0) {
+    return result;
+  }
+  double bracket[3];
   double x = start;
   bool endCondition = false;
   do {
@@ -638,6 +641,9 @@ Expression::Coordinate2D Expression::brentMinimum(char symbol, double ax, double
 }
 
 double Expression::nextIntersectionWithExpression(char symbol, double start, double step, double max, EvaluationAtAbscissa evaluation, Context & context, const Expression * expression) const {
+  if (start == max || step == 0.0) {
+    return NAN;
+  }
   double bracket[2];
   double result = NAN;
   static double precisionByGradUnit = 1E6;