Caffeine cache API has inconsistent behavior with differing types and between sync/async

[akervinen]

Play Version

2.9.1

API

Scala 2.13.12

Operating System

Windows 10

JDK

openjdk version "17.0.10" 2024-01-16 LTS
OpenJDK Runtime Environment Corretto-17.0.10.7.1 (build 17.0.10+7-LTS)
OpenJDK 64-Bit Server VM Corretto-17.0.10.7.1 (build 17.0.10+7-LTS, mixed mode, sharing)

Library Dependencies

object playcaffeinerepro extends PlayModule with SingleModule {

  def scalaVersion = "2.13.12"
  def playVersion = "2.9.1"
  def twirlVersion = "1.6.2"

  object test extends PlayTests

  override def ivyDeps = super.ivyDeps() ++ Agg(caffeine())
}

Expected Behavior

If current sync.get behavior is expected:

1. cache.set("foo", "bar")
2. cache.get[Int]("foo") == None
3. cache.getOrElseUpdate[Int]("foo")(1) == 1

But any consistent (and documented) behavior would be good.

Actual Behavior

Sync:

1. sync.set("foo", "bar")
2. sync.get[Int]("foo") == None
3. sync.getOrElseUpdate[Int]("foo")(1) throws ClassCastException (inconsistent with sync.get)

Async:

1. async.set("foo", "bar")
2. async.get[Int]("foo") == Some("bar") (inconsistent with sync.get, ignores type parameter)
3. async.getOrElseUpdate[Int]("foo")(Future(1)) throws ClassCastException (consistent with async.get)

I have not tested other cache implementations.

Reproducible Test Case

class CaffeineSpec extends PlaySpec with GuiceOneAppPerTest with Injecting {
  lazy val cache = inject[SyncCacheApi]
  lazy val asyncCache = inject[AsyncCacheApi]

  "Caffeine" when {
    "sync" should {
      "return None when type differs" in {
        cache.set("foo", "bar")
        val ret = cache.get[Int]("foo")
        ret mustBe None
      }

      "set via getOrElseUpdate" in {
        cache.set("foo", "bar")
        val ret = cache.getOrElseUpdate[Int]("foo")(1)
        ret mustBe 1
      }
    }

    "async" should {
      "return None when type differs" in {
        await(asyncCache.set("foo", "bar"))
        val ret = await(asyncCache.get[Int]("foo"))
        ret mustBe None
      }

      "set via getOrElseUpdate" in {
        await(asyncCache.set("foo", "bar"))
        val ret = await(asyncCache.getOrElseUpdate[Int]("foo")(Future.successful(1)))
        ret mustBe 1
      }
    }
  }
}

CaffeineSpec
Caffeine
  when sync
  - should return None when type differs
  - should set via getOrElseUpdate *** FAILED ***
    java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Integer (java.lang.String and java.lang.Integer are in module java.base of loader 'bootstrap')
    at scala.runtime.BoxesRunTime.unboxToInt(BoxesRunTime.java:99)
    at CaffeineSpec.$anonfun$new$4(CaffeineSpec.scala:26)
    ...
  when async
  - should return None when type differs *** FAILED ***
    Some("bar") was not equal to None (CaffeineSpec.scala:35)
  - should set via getOrElseUpdate *** FAILED ***
    java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Integer (java.lang.String and java.lang.Integer are in module java.base of loader 'bootstrap')
    at scala.runtime.BoxesRunTime.unboxToInt(BoxesRunTime.java:99)
    at CaffeineSpec.$anonfun$new$8(CaffeineSpec.scala:40)
    ...
Execution took 2.72s
4 tests, 1 passed, 3 failed

[mkurz]

Thanks @akervinen.
This results definitely seem a bit strange. Having a consistent behavior would definitely make sense.
Would you be interested in providing a pull request to fix this?
Thanks a lot!