koinConfiguration function to help declare, extend and reuse Koin con…

…figuration

projects/core/koin-core/src/commonMain/kotlin/org/koin/dsl/KoinApplication.kt

@@ -18,6 +18,7 @@ package org.koin.dsl
 import org.koin.core.KoinApplication
 import org.koin.core.module.KoinApplicationDslMarker
 
+//TODO Koin 4.1 - KoinAppDeclaration migration type to KoinConfiguration
 typealias KoinAppDeclaration = KoinApplication.() -> Unit
 
 /**

projects/core/koin-core/src/commonMain/kotlin/org/koin/dsl/KoinConfiguration.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2017-Present the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.koin.dsl
+
+import org.koin.core.KoinApplication
+import org.koin.core.module.KoinApplicationDslMarker
+
+//TODO Koin 4.1 - KoinAppDeclaration migration type to KoinConfiguration
+
+/**
+ * function helper to save a Koin configuration
+ *
+ * @param configuration - Koin configuration lambda
+ * @author Arnaud Giuliani
+ */
+@KoinApplicationDslMarker
+public fun koinConfiguration(configuration: KoinAppDeclaration): KoinAppDeclaration = configuration
+
+/**
+ * Includes other KoinConfiguration in the current KoinApplication
+ *
+ * @param configurations - Koin configurations
+ * @author Arnaud Giuliani
+ */
+public fun KoinApplication.includes(vararg configurations: KoinAppDeclaration?): KoinApplication {
+    configurations.forEach { it?.invoke(this@includes) }
+    return this
+}

projects/core/koin-core/src/commonTest/kotlin/org/koin/dsl/KoinAppCreationTest.kt

@@ -1,16 +1,21 @@
 package org.koin.dsl
 
+import org.koin.Simple.ComponentA
+import org.koin.Simple.ComponentB
 import org.koin.core.annotation.KoinInternalApi
 import org.koin.core.context.startKoin
 import org.koin.core.context.stopKoin
 import org.koin.core.error.KoinApplicationAlreadyStartedException
 import org.koin.core.logger.Level
+import org.koin.core.module.dsl.singleOf
+import org.koin.mp.KoinPlatform
 import org.koin.mp.KoinPlatformTools
 import org.koin.test.assertDefinitionsCount
 import org.koin.test.assertHasNoStandaloneInstance
 import kotlin.test.AfterTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
 import kotlin.test.fail
 
 @OptIn(KoinInternalApi::class)
@@ -79,6 +84,69 @@ class KoinAppCreationTest {
         KoinPlatformTools.defaultContext().get().logger.error("error")
     }
 
+    @Test
+    fun `allow declare a configuration`() {
+        val config = koinConfiguration {
+            printLogger(Level.DEBUG)
+        }
+
+        koinApplication(config)
+        startKoin(config)
+    }
+
+    @Test
+    fun `allow declare a configuration extension`() {
+        val config1 = koinConfiguration {
+            printLogger(Level.DEBUG)
+            modules(module {
+                singleOf(::ComponentA)
+            })
+        }
+
+        val config2 = koinConfiguration {
+            includes(config1)
+
+            modules(module {
+                singleOf(::ComponentB)
+            })
+        }
+
+        val k = koinApplication(config2).koin
+
+        assertEquals(
+            2,
+            k.instanceRegistry.instances.size
+        )
+        assertNotNull(k.getOrNull<ComponentB>())
+    }
+
+    fun init(config : KoinAppDeclaration? = null){
+        startKoin {
+            printLogger(Level.DEBUG)
+            includes(config)
+            modules(module {
+                singleOf(::ComponentA)
+            })
+        }
+    }
+
+    @Test
+    fun `allow declare a configuration extension - from function`() {
+        init()
+        assertNotNull(KoinPlatform.getKoin().getOrNull<ComponentA>())
+        stopKoin()
+
+        init {
+            modules(
+                module {
+                    singleOf(::ComponentB)
+                }
+            )
+        }
+        assertNotNull(KoinPlatform.getKoin().getOrNull<ComponentB>())
+        stopKoin()
+    }
+
 //    @Test
 //    fun `allow declare a print logger level`() {
 //        startKoin {