fix: UBs

Author: Becheler

include/boost/graph/relax.hpp

@@ -29,11 +29,15 @@ template < class T > struct closed_plus
 
     T operator()(const T& a, const T& b) const
     {
-        using namespace std;
         if (a == inf)
             return inf;
         if (b == inf)
             return inf;
+        // saturate to avoid signed overflow (e.g. negative cycles)
+        if (b > 0 && a > (std::numeric_limits< T >::max)() - b)
+            return inf;
+        if (b < 0 && a < (std::numeric_limits< T >::lowest)() - b)
+            return (std::numeric_limits< T >::lowest)();
         return a + b;
     }
 };

test/bundled_properties.cpp

@@ -76,10 +76,10 @@ struct Highway
     }
 
     string name;
-    double miles;
-    int speed_limit;
-    int lanes;
-    bool divided;
+    double miles = 0;
+    int speed_limit = 65;
+    int lanes = 4;
+    bool divided = true;
 };
 
 std::ostream& operator<<(std::ostream& out, const Highway& highway)