[BUG]: InMemoryBlockingCache is not thread-safe

[masclot]

[BUG]: InMemoryBlockingCache is not thread-safe

[masclot]

Sample test within InMemoryBlockingCacheTest that would fail with the current implementation:

  @Test
  fun testSequentiality() = runBlocking {
    val first = Job()
    val second = Job()

    val cache = cacheFactory.create<String>()
    val firstUpdate = cache.updateAsync {
      first.join()
      "first"
    }
    val secondUpdate = cache.updateAsync {
      second.join()
      "second"
    }
    second.complete()
    testCoroutineDispatchers.advanceUntilIdle()
    first.complete()
    testCoroutineDispatchers.advanceUntilIdle()
    firstUpdate.await()
    secondUpdate.await()
    assertThat(awaitCompletion(cache.readAsync())).isEqualTo("second")
  }

[BenHenning]

Ah I didn't realize that Job could be used as a stand-in replacement for a completable future--that's actually really useful to know.

It's great you devised a test that should fail. It looks like it should be consistent, but I can't be sure without running it. That should be a great test to use for high confidence verification of the final implementation.