Always collect stateIn on Main thread (GH-7)

Author: rickclephas

kmm-viewmodel-core/src/androidMain/kotlin/com/rickclephas/kmm/viewmodel/StateFlow.kt

@@ -1,7 +1,7 @@
 package com.rickclephas.kmm.viewmodel
 
-import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.*
+import kotlin.coroutines.CoroutineContext
 
 /**
  * @see kotlinx.coroutines.flow.MutableStateFlow
@@ -18,7 +18,7 @@ public actual inline fun <T> MutableStateFlow(
 @Suppress("NOTHING_TO_INLINE")
 public actual inline fun <T> Flow<T>.stateIn(
     viewModelScope: ViewModelScope,
-    coroutineScope: CoroutineScope,
+    coroutineContext: CoroutineContext,
     started: SharingStarted,
     initialValue: T
-): StateFlow<T> = stateIn(coroutineScope, started, initialValue)
+): StateFlow<T> = flowOn(coroutineContext).stateIn(viewModelScope.coroutineScope, started, initialValue)

kmm-viewmodel-core/src/appleMain/kotlin/com/rickclephas/kmm/viewmodel/StateFlow.kt

@@ -90,15 +90,16 @@ private class SubscriptionCountFlow(
  */
 public actual fun <T> Flow<T>.stateIn(
     viewModelScope: ViewModelScope,
-    coroutineScope: CoroutineScope,
+    coroutineContext: CoroutineContext,
     started: SharingStarted,
     initialValue: T
 ): StateFlow<T> {
-    // Similar to the kotlinx.coroutines implementation, but using our custom MutableStateFlowImpl.
+    // Similar to kotlinx.coroutines, but using our custom MutableStateFlowImpl and CoroutineContext logic.
     // https://github.com/Kotlin/kotlinx.coroutines/blob/6dfabf763fe9fc91fbb73eb0f2d5b488f53043f1/kotlinx-coroutines-core/common/src/flow/operators/Share.kt#L135
     val scope = viewModelScope.asImpl()
+    val upstream = flowOn(coroutineContext)
     val state = MutableStateFlowImpl(scope, MutableStateFlow(initialValue))
-    val job = coroutineScope.launchSharing(EmptyCoroutineContext, this, state, started, initialValue)
+    val job = scope.coroutineScope.launchSharing(EmptyCoroutineContext, upstream, state, started, initialValue)
     return ReadonlyStateFlow(state, job)
 }
 

kmm-viewmodel-core/src/commonMain/kotlin/com/rickclephas/kmm/viewmodel/StateFlow.kt

@@ -1,10 +1,10 @@
 package com.rickclephas.kmm.viewmodel
 
-import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
+import kotlin.coroutines.CoroutineContext
 
 /**
  * @see kotlinx.coroutines.flow.MutableStateFlow
@@ -19,7 +19,7 @@ public expect fun <T> MutableStateFlow(
  */
 public expect fun <T> Flow<T>.stateIn(
     viewModelScope: ViewModelScope,
-    coroutineScope: CoroutineScope,
+    coroutineContext: CoroutineContext,
     started: SharingStarted,
     initialValue: T
 ): StateFlow<T>

kmm-viewmodel-core/src/commonMain/kotlin/com/rickclephas/kmm/viewmodel/StateFlowUtils.kt

@@ -3,8 +3,7 @@ package com.rickclephas.kmm.viewmodel
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.plus
-import kotlin.coroutines.CoroutineContext
+import kotlin.coroutines.EmptyCoroutineContext
 
 /**
  * @see kotlinx.coroutines.flow.stateIn
@@ -14,15 +13,4 @@ public inline fun <T> Flow<T>.stateIn(
     viewModelScope: ViewModelScope,
     started: SharingStarted,
     initialValue: T
-): StateFlow<T> = stateIn(viewModelScope, viewModelScope.coroutineScope, started, initialValue)
-
-/**
- * @see kotlinx.coroutines.flow.stateIn
- */
-@Suppress("NOTHING_TO_INLINE")
-public inline fun <T> Flow<T>.stateIn(
-    viewModelScope: ViewModelScope,
-    context: CoroutineContext,
-    started: SharingStarted,
-    initialValue: T
-): StateFlow<T> = stateIn(viewModelScope, viewModelScope.coroutineScope + context, started, initialValue)
+): StateFlow<T> = stateIn(viewModelScope, EmptyCoroutineContext, started, initialValue)