Remove compositionHash usage due duplication bug (#7)

• fix multiple view models in same destination leads to crush
• fix multiple navControllers in same destination uses same DataStorage

example/composeApp/src/commonMain/kotlin/content/examples/NestedNavigation.kt

@@ -1,9 +1,10 @@
 package content.examples
 
 import androidx.compose.foundation.border
-import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import com.composegears.tiamat.Navigation
@@ -13,14 +14,11 @@ import content.examples.common.SimpleScreen
 
 val NestedNavigationRoot by navDestination<Unit> {
     SimpleScreen("Nested navigation") {
-        Box(
-            Modifier
-                .padding(32.dp)
-                .border(4.dp, MaterialTheme.colorScheme.onSurface)
-                .padding(4.dp)
+        Column(
+            horizontalAlignment = Alignment.CenterHorizontally,
+            modifier = Modifier.padding(16.dp)
         ) {
-            val nestedNavController = rememberNavController(
-                key = "nestedNavController",
+            val nestedNavController1 = rememberNavController(
                 startDestination = SimpleForwardBackRoot,
                 destinations = arrayOf(
                     SimpleForwardBackRoot,
@@ -29,7 +27,31 @@ val NestedNavigationRoot by navDestination<Unit> {
                     SimpleForwardBackRootScreen3,
                 )
             )
-            Navigation(nestedNavController)
+            val nestedNavController2 = rememberNavController(
+                startDestination = SimpleForwardBackRoot,
+                destinations = arrayOf(
+                    SimpleForwardBackRoot,
+                    SimpleForwardBackRootScreen1,
+                    SimpleForwardBackRootScreen2,
+                    SimpleForwardBackRootScreen3,
+                )
+            )
+            Navigation(
+                navController = nestedNavController1,
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(8.dp)
+                    .border(4.dp, MaterialTheme.colorScheme.onSurface)
+                    .padding(4.dp)
+            )
+            Navigation(
+                navController = nestedNavController2,
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(8.dp)
+                    .border(4.dp, MaterialTheme.colorScheme.onSurface)
+                    .padding(4.dp)
+            )
         }
     }
 }

library/build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
 }
 
 val libName = "io.github.composegears"
-val libVersion = "1.0.0"
+val libVersion = "1.0.1"
 
 group = libName
 version = libVersion

library/src/commonMain/kotlin/com/composegears/tiamat/Compose.kt

@@ -67,26 +67,17 @@ fun rememberNavController(
     destinations: Array<NavDestination<*>>
 ): NavController {
     val parent = LocalNavController.current
-    val parentDataStorage = LocalDataStore.current
-    val navDataStore =
-        if (parentDataStorage == null) rootDataStore()
-        else {
-            val storageKey = "DataStore#" + currentCompositeKeyHash.toString(16)
-            parentDataStorage.data.getOrPut(storageKey) { DataStorage() } as DataStorage
-        }
-
+    val parentDataStorage = LocalDataStore.current ?: rootDataStore()
     fun createNavController(state: Map<String, Any?>?) =
         NavController(
             parent = parent,
             key = key,
             storageMode = storageMode ?: parent?.storageMode ?: ResetOnDataLoss,
             startDestination = startDestination,
             savedState = state,
-            dataStorage = navDataStore,
             destinations = destinations
         ).apply {
-            if (storageMode == ResetOnDataLoss && navDataStore.data.isEmpty()) reset()
-            else restoreFromSavedState()
+            restoreState(parentDataStorage)
         }
     return rememberSaveable(
         saver = Saver(
@@ -214,7 +205,7 @@ fun Navigation(
             CompositionLocalProvider(
                 LocalSaveableStateRegistry provides saveRegistry,
                 LocalDataStore provides entryStorage,
-                LocalNavController provides navController
+                LocalNavController provides navController,
             ) {
                 DestinationContent(it.destination)
             }
@@ -272,26 +263,37 @@ fun <Args> NavDestinationScope<Args>.navArgsOrNull(): Args? {
 @Suppress("UNCHECKED_CAST", "CastToNullableType", "UnusedReceiverParameter")
 fun <Result> NavDestinationScope<*>.navResult(): Result? {
     val store = LocalDataStore.current ?: error("Store not bound")
-    val result = remember { store.data[KEY_NAV_RESULT] as Result? }
-    return result
+    return remember { store.data[KEY_NAV_RESULT] as Result? }
 }
 
 /**
  * Provide (create or restore) viewModel instance bound to navigation entry
  *
- * @param key provides unique key to create viewModel
  * @param provider default viewModel instance provider
  */
+
 @Composable
-@Suppress("UNCHECKED_CAST", "CastToNullableType", "UnusedReceiverParameter")
+inline fun <reified Model : TiamatViewModel> NavDestinationScope<*>.rememberViewModel(
+    noinline provider: () -> Model
+): Model = rememberViewModel(className<Model>(), provider)
+
+/**
+ * Recommended to use `rememberViewModel(key, provider)` instead
+ *
+ * Provide (create or restore) viewModel instance bound to navigation entry
+ *
+ * @param key provides unique key part
+ * @param provider default viewModel instance provider
+ */
+@Composable
+@Suppress("UNCHECKED_CAST", "UnusedReceiverParameter")
 fun <Model : TiamatViewModel> NavDestinationScope<*>.rememberViewModel(
-    key: String? = null,
+    key: String,
     provider: () -> Model
 ): Model {
     val store = LocalDataStore.current ?: error("Store not bound")
-    val compositionHash = currentCompositeKeyHash
     return remember {
-        val storeKey = "Model#" + (key ?: compositionHash.toString(16))
+        val storeKey = "Model#$key"
         store.data.getOrPut(storeKey, provider) as Model
     }
 }

library/src/commonMain/kotlin/com/composegears/tiamat/NavController.kt

@@ -16,15 +16,21 @@ class NavController internal constructor(
     val key: Any?,
     val storageMode: StorageMode,
     val startDestination: NavDestination<*>?,
-    internal val dataStorage: DataStorage,
     private val savedState: Map<String, Any?>?,
     private val destinations: Array<NavDestination<*>>
 ) {
     companion object {
+
+        private var nextUUID = 0L
+
         const val KEY_CURRENT = "current"
         const val KEY_BACKSTACK = "backStack"
+        const val KEY_UUID = "uuid"
     }
 
+    // needs to be restored asap not to rent extra uuid's
+    private val uuid: Long = (savedState?.get(KEY_UUID) as? Long) ?: nextUUID++
+
     /**
      * provides current active NavDestination as State object
      */
@@ -43,6 +49,8 @@ class NavController internal constructor(
 
     internal var currentNavEntry by mutableStateOf<NavEntry?>(null)
         private set
+    internal var dataStorage: DataStorage = DataStorage()
+        private set
     internal var isForwardTransition = true
         private set
     internal var isInitialTransition = true
@@ -51,6 +59,8 @@ class NavController internal constructor(
         private set
 
     init {
+        // ensure next uuid will be unique after restoring state of this one
+        nextUUID = maxOf(nextUUID, uuid + 1)
         val namesSet = mutableSetOf<String>()
         val duplicates = arrayListOf<String>()
         destinations.onEach {
@@ -202,25 +212,33 @@ class NavController internal constructor(
         }
     }
 
-    internal fun reset() {
+    internal fun toSavedState() = currentNavEntry?.let { entry ->
+        mapOf(
+            KEY_UUID to uuid,
+            KEY_CURRENT to entry.apply { saveState() }.toSavedState(storageMode),
+            KEY_BACKSTACK to backStack.map { it.toSavedState(storageMode) }
+        )
+    }
+
+    internal fun restoreState(parentDataStorage: DataStorage) {
+        val storageKey = "DataStore#$uuid"
+        dataStorage = parentDataStorage.data.getOrPut(storageKey) { DataStorage() } as DataStorage
+        if (storageMode == StorageMode.DataStore.ResetOnDataLoss && dataStorage.data.isEmpty()) reset()
+        else restoreFromSavedState()
+    }
+
+    private fun reset() {
         backStack.clear()
         setCurrentNavEntry(null, false)
         if (startDestination != null) navigate(startDestination)
     }
 
-    internal fun restoreFromSavedState() {
+    private fun restoreFromSavedState() {
         savedState?.let(::restoreFromSavedState)
         if (currentNavEntry == null && startDestination != null)
             navigate(startDestination)
     }
 
-    internal fun toSavedState() = currentNavEntry?.let {
-        mapOf(
-            KEY_CURRENT to currentNavEntry?.apply { saveState() }?.toSavedState(storageMode),
-            KEY_BACKSTACK to backStack.map { it.toSavedState(storageMode) }
-        )
-    }
-
     @Suppress("UNCHECKED_CAST")
     private fun restoreFromSavedState(savedState: Map<String, Any?>) {
         runCatching {

library/src/commonMain/kotlin/com/composegears/tiamat/NavEntry.kt

@@ -7,13 +7,10 @@ import androidx.compose.runtime.saveable.SaveableStateRegistry
  *
  * Hold nav entry information and allow to save/restore state base on storage mode
  */
-internal class NavEntry(
+internal class NavEntry private constructor(
+    val uuid: Long,
     val destination: NavDestination<*>,
     var navArgs: Any? = null,
-    var navResult: Any? = null,
-    var entryStorage: DataStorage? = null,
-    var savedState: Map<String, List<Any?>>? = null,
-    var savedStateRegistry: SaveableStateRegistry? = null,
 ) {
     companion object {
 
@@ -30,20 +27,28 @@ internal class NavEntry(
             storageMode: StorageMode,
             destinations: Array<NavDestination<*>>,
         ) = NavEntry(
+            uuid = this[KEY_UUID] as Long,
             destination = (this[KEY_NAME] as String).let { name -> destinations.first { it.name == name } },
-            savedState = this[KEY_SAVED_STATE] as? Map<String, List<Any?>>?,
         ).also {
-            it.uuid = this[KEY_UUID] as Long
+            // ensure next uuid will be unique after restoring state of this one
             nextUUID = maxOf(nextUUID, it.uuid + 1)
+            it.savedState = this[KEY_SAVED_STATE] as? Map<String, List<Any?>>?
             if (storageMode == StorageMode.Savable) {
                 it.navArgs = this[KEY_NAV_ARGS]
                 it.navResult = this[KEY_NAV_RESULT]
             }
         }
     }
 
-    internal var uuid: Long = nextUUID++
-        private set
+    var navResult: Any? = null
+    var entryStorage: DataStorage? = null
+    var savedState: Map<String, List<Any?>>? = null
+    var savedStateRegistry: SaveableStateRegistry? = null
+
+    constructor(
+        destination: NavDestination<*>,
+        navArgs: Any? = null,
+    ) : this(nextUUID++, destination, navArgs)
 
     internal fun saveState() {
         savedState = savedStateRegistry?.performSave()

library/src/commonMain/kotlin/com/composegears/tiamat/Utils.kt

@@ -0,0 +1,8 @@
+package com.composegears.tiamat
+
+/**
+ * We can not call T::class in @Composable functions,
+ *
+ * workaround is to call it outside of @Composable via regular inline fun
+ */
+inline fun <reified T : Any> className(): String = T::class.qualifiedName!!