Fix accidental division by zero

Author: cschreib

libjsonexpr/src/functions.cpp

@@ -89,7 +89,7 @@ bool check_overflow_sub(number_integer_t lhs, number_integer_t rhs) {
 }
 
 bool check_overflow_mul(number_integer_t lhs, number_integer_t rhs) {
-    return std::abs(lhs) > int_max / std::abs(rhs);
+    return rhs != 0 && std::abs(lhs) > int_max / std::abs(rhs);
 }
 
 #define MATHS_OPERATOR(NAME, OPERATOR)                                                             \

tests/src/number.cpp

@@ -108,6 +108,10 @@ TEST_CASE("muldiv", "[maths]") {
     }
 
     SECTION("int") {
+        CHECK(evaluate("2*1") == "2"_json);
+        CHECK(evaluate("1*2") == "2"_json);
+        CHECK(evaluate("1*0") == "0"_json);
+        CHECK(evaluate("0*1") == "0"_json);
         CHECK(evaluate("2*4") == "8"_json);
         CHECK(evaluate("4/2") == "2"_json);
         CHECK(evaluate("2/4") == "0"_json);