Fix scope resolution in inner solo scope root

Author: arnaudgiuliani

projects/core/koin-core/src/commonMain/kotlin/org/koin/core/resolution/CoreResolver.kt

@@ -128,7 +128,7 @@ class CoreResolver(
         scope: Scope,
         ctx: ResolutionContext,
     ): T? {
-        val parentScope = if (scope.linkedScopes.size > 1) flatten(scope.linkedScopes) else scope.linkedScopes
+        val parentScope = flatten(scope.linkedScopes)
         return parentScope.firstNotNullOfOrNull {
             ctx.logger.debug("|- ? ${ctx.debugTag} look in scope '${it.id}'")
             val instanceContext = if (!it.isRoot) ctx.newContextForScope(it) else ctx
@@ -164,9 +164,9 @@ fun flatten(scopes: List<Scope>): Set<Scope> {
         if (!flatten.add(current)) {
             continue
         }
-        for (module in current.linkedScopes) {
-            if (module !in flatten) {
-                stack += module
+        for (scope in current.linkedScopes) {
+            if (scope !in flatten) {
+                stack += scope
             }
         }
     }

projects/core/koin-core/src/commonTest/kotlin/org/koin/core/ScopeTest.kt

@@ -199,4 +199,30 @@ class ScopeTest {
         assertEquals(id, single.id)
         scope.close()
     }
+
+    @Test
+    fun scope_regression_test(){
+        startKoin {
+            modules(
+                module {
+                    single<Unit> {}
+                    scope(named("one")) {}
+                    scope(named("two")) {
+                        scoped<String> {
+                            get<Unit>().toString() // gets Unit from the root scope
+                        }
+                    }
+                },
+            )
+        }.run {
+            val one = koin.createScope("one", named("one"))
+            val two = koin.createScope("two", named("two")).apply {
+                unlink(getScope("_root_"))
+                linkTo(one)
+            }
+            // in 4.1.0-Beta11 -> prints "kotlin.Unit"
+            // in 4.1.0-RC1 -> throws NoDefinitionFoundException
+            assertEquals(Unit.toString(),two.get<String>())
+        }
+    }
 }