fix: Initialize call in MultiProvider never completes when listening to non-completing flow (#186)

Signed-off-by: penguindan <daniel.seunkim@gmail.com>

Author: PenguinDan

kotlin-sdk/src/commonMain/kotlin/dev/openfeature/kotlin/sdk/OpenFeatureAPI.kt

@@ -10,8 +10,6 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
-import kotlinx.coroutines.cancel
-import kotlinx.coroutines.cancelChildren
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.FlowCollector
 import kotlinx.coroutines.flow.MutableSharedFlow
@@ -26,7 +24,6 @@ object OpenFeatureAPI {
     private var setProviderJob: Job? = null
     private var setEvaluationContextJob: Job? = null
     private var observeProviderEventsJob: Job? = null
-    private var providerEventObservationScope: CoroutineScope? = null
 
     private val NOOP_PROVIDER = NoOpProvider()
     private var provider: FeatureProvider = NOOP_PROVIDER
@@ -242,8 +239,6 @@ object OpenFeatureAPI {
         observeProviderEventsJob?.cancel(
             CancellationException("Provider event observe job was cancelled due to shutdown")
         )
-        providerEventObservationScope?.coroutineContext?.cancelChildren()
-        providerEventObservationScope?.coroutineContext?.cancel()
         clearProvider()
     }
 

kotlin-sdk/src/commonMain/kotlin/dev/openfeature/kotlin/sdk/multiprovider/MultiProvider.kt

@@ -10,6 +10,10 @@ import dev.openfeature.kotlin.sdk.Value
 import dev.openfeature.kotlin.sdk.events.OpenFeatureProviderEvents
 import dev.openfeature.kotlin.sdk.events.toOpenFeatureStatusError
 import dev.openfeature.kotlin.sdk.exceptions.OpenFeatureError
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.async
 import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.coroutineScope
@@ -21,6 +25,7 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
 
 /**
  * Type alias for a function that evaluates a feature flag using a FeatureProvider.
@@ -154,6 +159,8 @@ class MultiProvider(
         }
     }
 
+    private var observeProviderEventsJob: Job? = null
+
     /**
      * @return Number of unique providers
      */
@@ -169,20 +176,27 @@ class MultiProvider(
      */
     override suspend fun initialize(initialContext: EvaluationContext?) {
         coroutineScope {
-            // Listen to events emitted by providers to emit our own set of events
-            // according to https://openfeature.dev/specification/appendix-a/#status-and-event-handling
-            childFeatureProviders.forEach { provider ->
-                provider.observe()
-                    .onEach { event ->
-                        handleProviderEvent(provider, event)
-                    }
-                    .launchIn(this)
+            observeProviderEventsJob?.cancel(
+                cause = CancellationException("Observe provider events job cancelled due to new initialize call")
+            )
+            observeProviderEventsJob = CoroutineScope(this.coroutineContext + SupervisorJob()).launch {
+                // Listen to events emitted by providers to emit our own set of events
+                // according to https://openfeature.dev/specification/appendix-a/#status-and-event-handling
+                childFeatureProviders.forEach { provider ->
+                    provider.observe()
+                        .onEach { event ->
+                            handleProviderEvent(provider, event)
+                        }
+                        .launchIn(this)
+                }
             }
 
-            // State updates captured by observing individual Feature Flag providers
-            childFeatureProviders
-                .map { async { it.initialize(initialContext) } }
-                .awaitAll()
+            launch {
+                // State updates captured by observing individual Feature Flag providers
+                childFeatureProviders
+                    .map { async { it.initialize(initialContext) } }
+                    .awaitAll()
+            }
         }
     }
 
@@ -221,6 +235,10 @@ class MultiProvider(
      * This allows providers to clean up resources and complete any pending operations.
      */
     override fun shutdown() {
+        observeProviderEventsJob?.cancel(
+            cause = CancellationException("Observe provider events job cancelled due to shutdown")
+        )
+
         val shutdownErrors = mutableListOf<Pair<String, Throwable>>()
         childFeatureProviders.forEach { provider ->
             try {

kotlin-sdk/src/commonTest/kotlin/dev/openfeature/kotlin/sdk/multiprovider/MultiProviderTests.kt

@@ -18,6 +18,7 @@ import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.test.advanceUntilIdle
 import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.withTimeout
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFailsWith
@@ -368,6 +369,17 @@ class MultiProviderTests {
         assertTrue(suppressedMessages.any { it.contains("Provider 'bad1' shutdown failed: oops1") })
         assertTrue(suppressedMessages.any { it.contains("Provider '<unnamed>' shutdown failed: oops2") })
     }
+
+    @Test
+    fun initializeFunctionCompletesWhenObservingNeverCompletingFlows() = runTest {
+        val fakeEventProvider = FakeEventProvider(name = "ok")
+
+        // Should complete immediately
+        withTimeout(1000) {
+            val multi = MultiProvider(listOf(fakeEventProvider))
+            multi.initialize(null)
+        }
+    }
 }
 
 // Helpers