Stack overflow regression of recursive arbOption

typelevel · Aug 6, 2019 · f328e24 · f328e24
1 parent 1e83007
commit f328e24
Show file tree

Hide file tree

Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/jvm/src/test/scala/org/scalacheck/ArbitrarySpecification.scala b/jvm/src/test/scala/org/scalacheck/ArbitrarySpecification.scala
@@ -23,6 +23,19 @@ object ArbitrarySpecification extends Properties("Arbitrary") {
   property("arbOption coverage") =
     exists(genOptionUnits) { case (a, b) => a.isDefined != b.isDefined }
 
+  private[this] final case class Recur(opt: Option[Recur])
+
+  private[this] implicit def arbRecur: Arbitrary[Recur] = Arbitrary {
+    Arbitrary.arbitrary[Option[Recur]]
+      .map(Recur(_))
+  }
+
+  property("arbitrary[Recur]") = {
+    Prop.forAll { recOpt: Recur =>
+      Prop.passed
+    }
+  }
+
   property("arbEnum") = {
     Gen.listOfN(100, arbitrary[TimeUnit]).sample.get.toSet == TimeUnit.values.toSet
   }

diff --git a/src/main/scala/org/scalacheck/Arbitrary.scala b/src/main/scala/org/scalacheck/Arbitrary.scala
@@ -336,7 +336,7 @@ private[scalacheck] sealed trait ArbitraryLowPriority {
 
   /** Arbitrary instance of the Option type */
   implicit def arbOption[T](implicit a: Arbitrary[T]): Arbitrary[Option[T]] =
-    Arbitrary(Gen.option(a.arbitrary))
+    Arbitrary(Gen.option(Gen.delay(a.arbitrary)))
 
   /** Arbitrary instance of the Either type */
   implicit def arbEither[T, U](implicit at: Arbitrary[T], au: Arbitrary[U]): Arbitrary[Either[T, U]] =