Merge pull request #167 from sangria-graphql/double-output-validation

Validate output double values

src/main/scala/sangria/schema/OutputValueCoercionException.scala

@@ -0,0 +1,3 @@
+package sangria.schema
+
+case class OutputValueCoercionException(message: String) extends Exception(message)

src/main/scala/sangria/schema/package.scala

@@ -65,7 +65,15 @@ package object schema {
     description = Some(
       "The `Float` scalar type represents signed double-precision fractional " +
       "values as specified by [IEEE 754](http://en.wikipedia.org/wiki/IEEE_floating_point)."),
-    coerceOutput = valueOutput,
+    coerceOutput = (v, _) ⇒  {
+      // .isNaN and .isInfinity box, we explicitly avoid that here
+      if (java.lang.Double.isNaN(v))
+        throw OutputValueCoercionException("Double value is NaN")
+      else if (java.lang.Double.isInfinite(v))
+        throw OutputValueCoercionException("Double value is infinite")
+      else
+        v
+    },
     coerceUserInput = {
       case i: Int ⇒ Right(i.toDouble)
       case i: Long ⇒ Right(i.toDouble)

src/test/scala/sangria/schema/CoercionSpec.scala

@@ -28,6 +28,19 @@ class CoercionSpec extends WordSpec with Matchers {
         FloatType.coerceOutput(123.456, Set.empty) should be (123.456)
       }
 
+      "Float is not allowed to be Nan" in {
+        an [OutputValueCoercionException] should be thrownBy
+          FloatType.coerceOutput(Double.NaN, Set.empty)
+      }
+
+      "Float is not allowed to be infinity" in {
+        an [OutputValueCoercionException] should be thrownBy
+          FloatType.coerceOutput(Double.PositiveInfinity, Set.empty)
+
+        an [OutputValueCoercionException] should be thrownBy
+          FloatType.coerceOutput(Double.NegativeInfinity, Set.empty)
+      }
+
       "BigDecimal" in {
         BigDecimalType.coerceOutput(BigDecimal("467356453726547623.37467823648763238479823"), Set.empty) should be (
           BigDecimal("467356453726547623.37467823648763238479823"))