Avoid deadlock in RealMutableStore (#658)

* Add test case

Signed-off-by: Amr Yousef <[email protected]>

* Always Release storeLock

Signed-off-by: Amr Yousef <[email protected]>

* Update kermit to 2.0.4 (#655)

Fixes #653 and #654

Signed-off-by: Scott Olcott <[email protected]>
Signed-off-by: Amr Yousef <[email protected]>

* Revert "Update kermit to 2.0.4 (#655)"

This reverts commit 76f34d4.

Signed-off-by: Amr Yousef <[email protected]>

---------

Signed-off-by: Amr Yousef <[email protected]>
Signed-off-by: Scott Olcott <[email protected]>
Co-authored-by: Scott Olcott <[email protected]>

Author: 2 people

store/src/commonMain/kotlin/org/mobilenativefoundation/store/store5/impl/RealMutableStore.kt

@@ -193,10 +193,13 @@ internal class RealMutableStore<Key : Any, Network : Any, Output : Any, Local :
     @AnyThread
     private suspend fun <Output : Any?> withThreadSafety(key: Key, block: suspend ThreadSafety.() -> Output): Output {
         storeLock.lock()
-        val threadSafety = requireNotNull(keyToThreadSafety[key])
-        val output = threadSafety.block()
-        storeLock.unlock()
-        return output
+        try {
+            val threadSafety = requireNotNull(keyToThreadSafety[key])
+            val output = threadSafety.block()
+            return output
+        } finally {
+            storeLock.unlock()
+        }
     }
 
     private suspend fun conflictsMightExist(key: Key): Boolean {

store/src/commonTest/kotlin/org/mobilenativefoundation/store/store5/StoreWithInMemoryCacheTests.kt

@@ -1,12 +1,21 @@
 package org.mobilenativefoundation.store.store5
 
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.async
+import kotlinx.coroutines.awaitAll
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.runTest
 import org.mobilenativefoundation.store.store5.impl.extensions.get
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertIs
+import kotlin.test.assertNotNull
 import kotlin.time.Duration.Companion.hours
 
 @FlowPreview
@@ -37,4 +46,87 @@ class StoreWithInMemoryCacheTests {
         assertEquals("result", c)
         assertEquals("result", d)
     }
+
+    @Test
+    fun storeDeadlock() =
+        testScope.runTest {
+            repeat(1000) {
+                val store =
+                    StoreBuilder
+                        .from(
+                            fetcher = Fetcher.of { key: Int -> "fetcher_${key}" },
+                            sourceOfTruth = SourceOfTruth.Companion.of(
+                                reader = { key ->
+                                    flow<String> {
+                                        emit("source_of_truth_${key}")
+                                    }
+                                },
+                                writer = { key: Int, local: String ->
+
+                                }
+                            )
+                        )
+                        .disableCache()
+                        .toMutableStoreBuilder(
+                            converter = object : Converter<String, String, String> {
+                                override fun fromNetworkToLocal(network: String): String {
+                                    return network
+                                }
+
+                                override fun fromOutputToLocal(output: String): String {
+                                    return output
+                                }
+                            },
+                        )
+                        .build(
+                            updater = object : Updater<Int, String, Unit> {
+                                var callCount = -1
+                                override suspend fun post(key: Int, value: String): UpdaterResult {
+                                    callCount += 1
+                                    if (callCount % 2 == 0) {
+                                        throw IllegalArgumentException(key.toString() + "value:$value")
+                                    } else {
+                                        return UpdaterResult.Success.Untyped("")
+                                    }
+                                }
+
+                                override val onCompletion: OnUpdaterCompletion<Unit>?
+                                    get() = null
+
+                            }
+                        )
+
+                val jobs = mutableListOf<Job>()
+                jobs.add(
+                    store.stream<Nothing>(StoreReadRequest.cached(1, refresh = true))
+                        .mapNotNull { it.dataOrNull() }
+                        .launchIn(CoroutineScope(Dispatchers.Default))
+                )
+                val job1 = store.stream<Nothing>(StoreReadRequest.cached(0, refresh = true))
+                    .mapNotNull { it.dataOrNull() }
+                    .launchIn(CoroutineScope(Dispatchers.Default))
+                jobs.add(
+                    store.stream<Nothing>(StoreReadRequest.cached(2, refresh = true))
+                        .mapNotNull { it.dataOrNull() }
+                        .launchIn(CoroutineScope(Dispatchers.Default)))
+                jobs.add(
+                    store.stream<Nothing>(StoreReadRequest.cached(3, refresh = true))
+                        .mapNotNull { it.dataOrNull() }
+                        .launchIn(CoroutineScope(Dispatchers.Default)))
+                job1.cancel()
+                assertEquals(
+                    expected = "source_of_truth_0",
+                    actual = store.stream<Nothing>(StoreReadRequest.cached(0, refresh = true))
+                        .mapNotNull { it.dataOrNull() }.first()
+                )
+                jobs.forEach {
+                    it.cancel()
+                    assertEquals(
+                        expected = "source_of_truth_0",
+                        actual = store.stream<Nothing>(StoreReadRequest.cached(0, refresh = true))
+                            .mapNotNull { it.dataOrNull() }.first()
+                    )
+                }
+            }
+        }
 }