#2085 - fix NaN and Infinity exception at JsonSerializer.Deserialize

Author: kcsombrio

LiteDB.Tests/Document/Json_Tests.cs

@@ -75,5 +75,24 @@ public void Json_Number_Deserialize_Test()
             JsonSerializer.Deserialize(positiveDouble.ToString("F1", CultureInfo.InvariantCulture)).Should().Be(positiveDouble);
             JsonSerializer.Deserialize(negativeDouble.ToString("F1", CultureInfo.InvariantCulture)).Should().Be(negativeDouble);
         }
+
+        [Fact]
+        public void Json_DoubleNaN_Tests()
+        {
+            BsonDocument doc = new BsonDocument();
+            doc["doubleNaN"] = double.NaN;
+            doc["doubleNegativeInfinity"] = double.NegativeInfinity;
+            doc["doublePositiveInfinity"] = double.PositiveInfinity;
+
+            // Convert to JSON
+            string json = JsonSerializer.Serialize(doc);
+
+            var bson = JsonSerializer.Deserialize(json);
+
+            // JSON standard converts NaN and Infinities to null, so deserialized values should not be double.NaN nor double.*Infinity
+            Assert.False(double.IsNaN(bson["doubleNaN"].AsDouble));
+            Assert.False(double.IsNegativeInfinity(bson["doubleNegativeInfinity"].AsDouble));
+            Assert.False(double.IsPositiveInfinity(bson["doublePositiveInfinity"].AsDouble));
+        }
     }
 }

LiteDB/Document/Json/JsonWriter.cs

@@ -71,7 +71,17 @@ private void WriteValue(BsonValue value)
                     break;
 
                 case BsonType.Double:
-                    _writer.Write(value.AsDouble.ToString("0.0########", _numberFormat));
+                    var d = value.AsDouble;
+
+                    if (double.IsNaN(d) || double.IsNegativeInfinity(d) || double.IsPositiveInfinity(d))
+                    {
+                        _writer.Write("null");
+                    }
+                    else
+                    {
+                        _writer.Write(value.AsDouble.ToString("0.0########", _numberFormat));
+                    }
+
                     break;
 
                 case BsonType.Binary: