fix: problems observed while refactoring Nimbus for Compose (#54)

* fixes problems observed while adapting Nimbus Compose to the new Core update strategy

* self-review

gradle.properties

@@ -13,7 +13,7 @@ kotlin.native.binary.memoryModel=experimental
 
 #POM CONFIGURATION
 POM_NAME=nimbus
-VERSION_NAME=1.0.0-alpha5
+VERSION_NAME=1.0.0-alpha
 POM_GROUP=br.com.zup.nimbus
 POM_DESCRIPTION=A framework to help implement Server-Driven UI in your apps natively.
 POM_INCEPTION_YEAR=2022

src/commonMain/kotlin/com/zup/nimbus/core/Nimbus.kt

@@ -15,7 +15,7 @@ import com.zup.nimbus.core.ui.coreUILibrary
 /**
  * The root scope of a nimbus application. Contains important objects like the logger and the httpClient.
  */
-class Nimbus(config: ServerDrivenConfig): CommonScope(
+open class Nimbus(config: ServerDrivenConfig): CommonScope(
   parent = null,
   states = (config.states ?: emptyList()) + ServerDrivenState("global", null),
 ) {

src/commonMain/kotlin/com/zup/nimbus/core/deserialization/ComponentDeserializer.kt

@@ -1,6 +1,7 @@
 package com.zup.nimbus.core.deserialization
 
 import com.zup.nimbus.core.log.Logger
+import com.zup.nimbus.core.tree.ServerDrivenEvent
 import com.zup.nimbus.core.tree.ServerDrivenNode
 
 class ComponentDeserializer(val logger: Logger, val node: ServerDrivenNode) {
@@ -58,8 +59,8 @@ class ComponentDeserializer(val logger: Logger, val node: ServerDrivenNode) {
     return deserializer.asMap(key)
   }
 
-  fun asAction(key: String): (Any?) -> Unit {
-    return deserializer.asAction(key)
+  fun asEvent(key: String): ServerDrivenEvent {
+    return deserializer.asEvent(key)
   }
 
   fun asStringOrNull(key: String): String? {
@@ -90,7 +91,7 @@ class ComponentDeserializer(val logger: Logger, val node: ServerDrivenNode) {
     return deserializer.asMapOrNull(key)
   }
 
-  fun asActionOrNull(key: String): ((Any?) -> Unit)? {
-    return deserializer.asActionOrNull(key)
+  fun asEventOrNull(key: String): ServerDrivenEvent? {
+    return deserializer.asEventOrNull(key)
   }
 }

src/commonMain/kotlin/com/zup/nimbus/core/deserialization/MapDeserializer.kt

@@ -1,5 +1,8 @@
 package com.zup.nimbus.core.deserialization
 
+import com.zup.nimbus.core.tree.ServerDrivenEvent
+import com.zup.nimbus.core.tree.dynamic.DynamicEvent
+
 class MapDeserializer {
   private var errors = ArrayList<String>()
   private var current: Map<String, Any?>? = null
@@ -72,13 +75,12 @@ class MapDeserializer {
     return emptyMap()
   }
 
-  private fun getAction(key: String, nullable: Boolean): ((Any?) -> Unit)? {
+  private fun getEvent(key: String, nullable: Boolean): ServerDrivenEvent? {
     val value = current?.get(key)
     if (nullable && value == null) return null
-    @Suppress("UNCHECKED_CAST")
-    if (value is Function1<*, *>) return value as (Any?) -> Unit
-    addTypeError("an array of Actions", key, value)
-    return { _ -> }
+    if (value is ServerDrivenEvent) return value
+    addTypeError("an event, i.e. an array of actions.", key, value)
+    return DynamicEvent("Unknown")
   }
 
   fun start(map: Map<String, Any?>?) {
@@ -134,8 +136,8 @@ class MapDeserializer {
     return getMap(key, false)!!
   }
 
-  fun asAction(key: String): (Any?) -> Unit {
-    return getAction(key, false)!!
+  fun asEvent(key: String): ServerDrivenEvent {
+    return getEvent(key, false)!!
   }
 
   fun asStringOrNull(key: String): String? {
@@ -166,7 +168,7 @@ class MapDeserializer {
     return getMap(key, true)
   }
 
-  fun asActionOrNull(key: String): ((Any?) -> Unit)? {
-    return getAction(key, true)
+  fun asEventOrNull(key: String): ServerDrivenEvent? {
+    return getEvent(key, true)
   }
 }

src/commonMain/kotlin/com/zup/nimbus/core/network/DefaultHttpClient.kt

@@ -13,9 +13,7 @@ import io.ktor.http.Headers
 import io.ktor.http.HttpMethod
 import kotlin.collections.set
 
-class DefaultHttpClient internal constructor (
-  engine: HttpClientEngine? = null,
-): com.zup.nimbus.core.network.HttpClient {
+class DefaultHttpClient (engine: HttpClientEngine? = null): com.zup.nimbus.core.network.HttpClient {
   constructor() : this(null)
 
   private val client = if (engine == null) HttpClient() else HttpClient(engine)

src/commonMain/kotlin/com/zup/nimbus/core/scope/Scope.kt

@@ -55,7 +55,7 @@ interface Scope {
 /**
  * Returns the closest Scope with the specified type.
  */
-internal inline fun <reified T: Scope> Scope.closestScopeWithType(): T? {
+inline fun <reified T: Scope> Scope.closestScopeWithType(): T? {
   var current: Scope? = this
   while (current != null && current !is T) current = current.parent
   return current?.let { current as T }

src/commonMain/kotlin/com/zup/nimbus/core/tree/dynamic/node/IfNode.kt

@@ -3,11 +3,17 @@ package com.zup.nimbus.core.tree.dynamic.node
 import com.zup.nimbus.core.ServerDrivenState
 import com.zup.nimbus.core.utils.valueOfKey
 
-// fixme: normally, in UI frameworks, if-else blocks completely remove the other branch from the tree and rebuilds it
+// fixme(1): normally, in UI frameworks, if-else blocks completely remove the other branch from the tree and rebuilds it
 //  when the condition changes. This is not being done here. On the positive side, states will never be lost when
 //  switching from true to false. On the other hand, we won't free up the memory for the if-else branch not currently
 //  rendered until the associated RootNode is unmounted. If we decide this to be a feature and not a bug, remove this
 //  commentary.
+//
+// fixme(2): we shouldn't try to run the components of Else if the condition is true; or the components of Then when
+//  the condition is false. Example: we may use an operation that expects something not to be null and this can only be
+//  guaranteed by the if's condition. By initializing both Then and Else no matter the condition value, we'll end up
+//  processing way more than we need and risk running operations that expect values different than the ones we have.
+//  PS: fixing the first issue automatically fixes this.
 /**
  * IfNode is a polymorphic DynamicNode that chooses only one of its original subtree (json) to render at a time. The
  * chosen subtree depends on the value of the property "condition". When "condition" is true and "Then" is a child of

src/commonMain/kotlin/com/zup/nimbus/core/ui/UILibrary.kt

@@ -29,22 +29,22 @@ open class UILibrary(
   private val actionObservers = mutableListOf<ActionHandler>()
   private val operations = mutableMapOf<String, OperationHandler>()
 
-  fun addAction(name: String, handler: ActionHandler): UILibrary {
+  open fun addAction(name: String, handler: ActionHandler): UILibrary {
     actions[name] = handler
     return this
   }
 
-  fun addActionInitializer(name: String, handler: ActionInitializationHandler): UILibrary {
+  open fun addActionInitializer(name: String, handler: ActionInitializationHandler): UILibrary {
     actionInitializers[name] = handler
     return this
   }
 
-  fun addActionObserver(observer: ActionHandler): UILibrary {
+  open fun addActionObserver(observer: ActionHandler): UILibrary {
     actionObservers.add(observer)
     return this
   }
 
-  fun addOperation(name: String, handler: OperationHandler): UILibrary {
+  open fun addOperation(name: String, handler: OperationHandler): UILibrary {
     operations[name] = handler
     return this
   }
@@ -65,11 +65,6 @@ open class UILibrary(
     return operations[name]
   }
 
-  /**
-   * Merges the given UILibrary into this UILibrary. This alters the current UILibrary.
-   *
-   * Attention: remember to override this method when extending this class.
-   */
   open fun merge(other: UILibrary): UILibrary {
     actions.putAll(other.actions)
     actionInitializers.putAll(other.actionInitializers)