From 33f1b5735dcfaeced3d54a0f1908606be2f0fa8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=EA=B9=80=ED=9D=AC=EB=A7=9D?=
 <105429536+esperar@users.noreply.github.com>
Date: Mon, 25 Sep 2023 19:03:04 +0900
Subject: [PATCH] Update `FlowResponseConverterFunctionProvider` Type Extension
 functions toClass() (#5201)

### Type of PR

Hello! While reviewing the Kotlin part of Armeria, I noticed that in the `FlowResponseConverterFunctionProvider` class, there's an extension function for `Type` used in the `createResponseConverterFunction()` function of `DelegatingResponseConverterFunctionProvider`. The `toClass()` function returns a type of `Class<*>?`.

<br>

In the past, when working with Kotlin, I found it beneficial to define extension functions that return nullable values with names following the `toXXXOrNull()` pattern. This made the code more understandable for me and my teammates, especially during maintenance.

<br>

Since the extension function is defined just below `createResponseConverterFunction()`, it may lead to questions like "Why use `toClass()?.let` here?" Adding `OrNull` to the function name can make the code more readable.

<br>

> I understand that naming conventions can vary among teams, and it may not be a critical issue. However, if you find the suggestion helpful, I'd appreciate it if you could consider applying the change.

---

```kt
private fun Type.toClassOrNull(): Class<*>? =
    when (this) {
        is ParameterizedType -> this.rawType as Class<*>
        is Class<*> -> this
        else -> null
    }
---
 .../common/kotlin/FlowResponseConverterFunctionProvider.kt    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kotlin/src/main/kotlin/com/linecorp/armeria/internal/common/kotlin/FlowResponseConverterFunctionProvider.kt b/kotlin/src/main/kotlin/com/linecorp/armeria/internal/common/kotlin/FlowResponseConverterFunctionProvider.kt
index aaf2d8cd984..7ccbfa10659 100644
--- a/kotlin/src/main/kotlin/com/linecorp/armeria/internal/common/kotlin/FlowResponseConverterFunctionProvider.kt
+++ b/kotlin/src/main/kotlin/com/linecorp/armeria/internal/common/kotlin/FlowResponseConverterFunctionProvider.kt
@@ -32,7 +32,7 @@ class FlowResponseConverterFunctionProvider : DelegatingResponseConverterFunctio
         responseConverter: ResponseConverterFunction
     ): ResponseConverterFunction? =
         returnType
-            .toClass()
+            .toClassOrNull()
             ?.let {
                 if (Flow::class.java.isAssignableFrom(it)) {
                     FlowResponseConverterFunction(responseConverter)
@@ -41,7 +41,7 @@ class FlowResponseConverterFunctionProvider : DelegatingResponseConverterFunctio
                 }
             }
 
-    private fun Type.toClass(): Class<*>? =
+    private fun Type.toClassOrNull(): Class<*>? =
         when (this) {
             is ParameterizedType -> this.rawType as Class<*>
             is Class<*> -> this