💥 implemented new handling of NaN and INF #70 #329 #388

- If an overflow occurs during parsing a number from a JSON text, an
exception (std::out_of_range for the moment, to be replaced by a
user-defined exception #244) is thrown so that the overflow is detected
early and roundtripping is guaranteed.
- NaN and INF floating-point values can be stored in a JSON value and
are not replaced by null. That is, the basic_json class behaves like
double in this regard (no exception occurs). However, NaN and INF are
serialized to “null”.
- Adjusted test cases appropriately.

src/json.hpp

@@ -263,16 +263,8 @@ struct external_constructor<value_t::number_float>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
     {
-        // replace infinity and NAN by null
+        j.m_type = value_t::number_float;
-        if (not std::isfinite(val))
+        j.m_value = val;
-        {
-            j = BasicJsonType{};
-        }
-        else
-        {
-            j.m_type = value_t::number_float;
-            j.m_value = val;
-        }
         j.assert_invariant();
     }
 };
@@ -6653,6 +6645,13 @@ class basic_json
         */
         void dump_float(number_float_t x)
         {
+            // NaN / inf
+            if (not std::isfinite(x) or std::isnan(x))
+            {
+                o.write("null", 4);
+                return;
+            }
+
             // special case for 0.0 and -0.0
             if (x == 0)
             {
@@ -11425,11 +11424,10 @@ basic_json_parser_74:
                 result.m_type = value_t::number_float;
                 result.m_value = val;
 
-                // replace infinity and NAN by null
+                // throw in case of infinity or NAN
                 if (not std::isfinite(result.m_value.number_float))
                 {
-                    result.m_type  = value_t::null;
+                    JSON_THROW(std::out_of_range("number overflow: " + get_token_string()));
-                    result.m_value = basic_json::json_value();
                 }
 
                 return true;

src/json.hpp.re2c

@@ -263,16 +263,8 @@ struct external_constructor<value_t::number_float>
     template<typename BasicJsonType>
     static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept
     {
-        // replace infinity and NAN by null
+        j.m_type = value_t::number_float;
-        if (not std::isfinite(val))
+        j.m_value = val;
-        {
-            j = BasicJsonType{};
-        }
-        else
-        {
-            j.m_type = value_t::number_float;
-            j.m_value = val;
-        }
         j.assert_invariant();
     }
 };
@@ -6653,6 +6645,13 @@ class basic_json
         */
         void dump_float(number_float_t x)
         {
+            // NaN / inf
+            if (not std::isfinite(x) or std::isnan(x))
+            {
+                o.write("null", 4);
+                return;
+            }
+
             // special case for 0.0 and -0.0
             if (x == 0)
             {
@@ -10459,11 +10458,10 @@ class basic_json
                 result.m_type = value_t::number_float;
                 result.m_value = val;
 
-                // replace infinity and NAN by null
+                // throw in case of infinity or NAN
                 if (not std::isfinite(result.m_value.number_float))
                 {
-                    result.m_type  = value_t::null;
+                    JSON_THROW(std::out_of_range("number overflow: " + get_token_string()));
-                    result.m_value = basic_json::json_value();
                 }
 
                 return true;

test/src/unit-cbor.cpp

@@ -33,6 +33,7 @@ SOFTWARE.
 using nlohmann::json;
 
 #include <fstream>
+#include <cmath>
 
 TEST_CASE("CBOR")
 {
@@ -744,13 +745,17 @@ TEST_CASE("CBOR")
                 SECTION("infinity")
                 {
                     json j = json::from_cbor(std::vector<uint8_t>({0xf9, 0x7c, 0x00}));
-                    CHECK(j == nullptr);
+                    json::number_float_t d = j;
+                    CHECK(not std::isfinite(d));
+                    CHECK(j.dump() == "null");
                 }
 
                 SECTION("NaN")
                 {
                     json j = json::from_cbor(std::vector<uint8_t>({0xf9, 0x7c, 0x01}));
-                    CHECK(j == nullptr);
+                    json::number_float_t d = j;
+                    CHECK(std::isnan(d));
+                    CHECK(j.dump() == "null");
                 }
             }
         }
@@ -1344,7 +1349,7 @@ TEST_CASE("CBOR roundtrips", "[hide]")
                     "test/data/nst_json_testsuite/test_parsing/y_number_after_space.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_double_close_to_zero.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_double_huge_neg_exp.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_int_with_exp.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_minus_zero.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_negative_int.json",
@@ -1356,9 +1361,9 @@ TEST_CASE("CBOR roundtrips", "[hide]")
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_exponent.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_fraction_exponent.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_exp.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_exponent.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_underflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_simple_int.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_simple_real.json",

test/src/unit-class_parser.cpp

@@ -272,7 +272,9 @@ TEST_CASE("parser class")
 
             SECTION("overflow")
             {
-                CHECK(json::parser("1.18973e+4932").parse() == json());
+                // overflows during parsing yield an exception
+                CHECK_THROWS_AS(json::parser("1.18973e+4932").parse() == json(), std::out_of_range);
+                CHECK_THROWS_WITH(json::parser("1.18973e+4932").parse() == json(), "number overflow: 1.18973e+4932");
             }
 
             SECTION("invalid numbers")

test/src/unit-constructor1.cpp

@@ -702,11 +702,17 @@ TEST_CASE("constructors")
 
         SECTION("infinity")
         {
-            // infinity is stored as null
+            // infinity is stored properly, but serialized to null
-            // should change in the future: https://github.com/nlohmann/json/issues/388
             json::number_float_t n(std::numeric_limits<json::number_float_t>::infinity());
             json j(n);
-            CHECK(j.type() == json::value_t::null);
+            CHECK(j.type() == json::value_t::number_float);
+
+            // check round trip of infinity
+            json::number_float_t d = j;
+            CHECK(d == n);
+
+            // check that inf is serialized to null
+            CHECK(j.dump() == "null");
         }
     }
 

test/src/unit-msgpack.cpp

@@ -1116,7 +1116,7 @@ TEST_CASE("MessagePack roundtrips", "[hide]")
                     "test/data/nst_json_testsuite/test_parsing/y_number_after_space.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_double_close_to_zero.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_double_huge_neg_exp.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_int_with_exp.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_minus_zero.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_negative_int.json",
@@ -1128,9 +1128,9 @@ TEST_CASE("MessagePack roundtrips", "[hide]")
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_exponent.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_fraction_exponent.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_exp.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_exponent.json",
-                    "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json",
+                    //"test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_real_underflow.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_simple_int.json",
                     "test/data/nst_json_testsuite/test_parsing/y_number_simple_real.json",

test/src/unit-regression.cpp

@@ -49,6 +49,7 @@ TEST_CASE("regression tests")
 
     SECTION("issue #70 - Handle infinity and NaN cases")
     {
+        /*
         SECTION("NAN value")
         {
             CHECK(json(NAN) == json());
@@ -60,6 +61,36 @@ TEST_CASE("regression tests")
             CHECK(json(INFINITY) == json());
             CHECK(json(json::number_float_t(INFINITY)) == json());
         }
+        */
+
+        // With 3.0.0, the semantics of this changed: NAN and infinity are
+        // stored properly inside the JSON value (no exception or conversion
+        // to null), but are serialized as null.
+        SECTION("NAN value")
+        {
+            json j1 = NAN;
+            CHECK(j1.is_number_float());
+            json::number_float_t f1 = j1;
+            CHECK(std::isnan(f1));
+
+            json j2 = json::number_float_t(NAN);
+            CHECK(j2.is_number_float());
+            json::number_float_t f2 = j2;
+            CHECK(std::isnan(f2));
+        }
+
+        SECTION("infinity")
+        {
+            json j1 = INFINITY;
+            CHECK(j1.is_number_float());
+            json::number_float_t f1 = j1;
+            CHECK(not std::isfinite(f1));
+
+            json j2 = json::number_float_t(INFINITY);
+            CHECK(j2.is_number_float());
+            json::number_float_t f2 = j2;
+            CHECK(not std::isfinite(f2));
+        }
     }
 
     SECTION("pull request #71 - handle enum type")
@@ -559,8 +590,8 @@ TEST_CASE("regression tests")
 
     SECTION("issue #329 - serialized value not always can be parsed")
     {
-        json j = json::parse("22e2222");
+        CHECK_THROWS_AS(json::parse("22e2222"), std::out_of_range);
-        CHECK(j == json());
+        CHECK_THROWS_WITH(json::parse("22e2222"), "number overflow: 22e2222");
     }
 
     SECTION("issue #366 - json::parse on failed stream gets stuck")

test/src/unit-testsuites.cpp

@@ -460,7 +460,6 @@ TEST_CASE("nst's JSONTestSuite")
                         "test/data/nst_json_testsuite/test_parsing/y_number_after_space.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_double_close_to_zero.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_double_huge_neg_exp.json",
-                        "test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_int_with_exp.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_minus_zero.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_negative_int.json",
@@ -472,9 +471,7 @@ TEST_CASE("nst's JSONTestSuite")
                         "test/data/nst_json_testsuite/test_parsing/y_number_real_exponent.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_real_fraction_exponent.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_exp.json",
-                        "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_exponent.json",
-                        "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_real_underflow.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_simple_int.json",
                         "test/data/nst_json_testsuite/test_parsing/y_number_simple_real.json",
@@ -765,9 +762,6 @@ TEST_CASE("nst's JSONTestSuite")
         {
             for (auto filename :
                     {
-                        // we currently do not limit exponents
-                        "test/data/nst_json_testsuite/test_parsing/i_number_neg_int_huge_exp.json",
-                        "test/data/nst_json_testsuite/test_parsing/i_number_pos_double_huge_exp.json",
                         // we do not pose a limit on nesting
                         "test/data/nst_json_testsuite/test_parsing/i_structure_500_nested_arrays.json",
                         // we silently ignore BOMs
@@ -787,6 +781,26 @@ TEST_CASE("nst's JSONTestSuite")
             }
         }
 
+        // numbers that overflow during parsing
+        SECTION("i/y -> n (out of range)")
+        {
+            for (auto filename :
+                    {
+                        "test/data/nst_json_testsuite/test_parsing/i_number_neg_int_huge_exp.json",
+                        "test/data/nst_json_testsuite/test_parsing/i_number_pos_double_huge_exp.json",
+                        "test/data/nst_json_testsuite/test_parsing/y_number_huge_exp.json",
+                        "test/data/nst_json_testsuite/test_parsing/y_number_real_neg_overflow.json",
+                        "test/data/nst_json_testsuite/test_parsing/y_number_real_pos_overflow.json"
+                    }
+                )
+            {
+                CAPTURE(filename);
+                std::ifstream f(filename);
+                json j;
+                CHECK_THROWS_AS(j << f, std::out_of_range);
+            }
+        }
+
         SECTION("i -> n")
         {
             for (auto filename :