From b9197933ed8ec114812eef7e48478629af2bf46d Mon Sep 17 00:00:00 2001
From: Jannes Heinrich <jannes.heinrich@otto.de>
Date: Thu, 9 Apr 2020 16:48:38 +0200
Subject: [PATCH] Create empty produces for spring endpoint if the return type
 is void or Unit (#50)

---
 .../extensions/ProducesSpringExtension.kt     | 12 ++++++----
 .../redirect/RedirectTestController.kt        | 12 ++++++++++
 .../redirect/SpringControllerRedirectTest.kt  | 24 +++++++++++++++++++
 3 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/spring/src/main/kotlin/de/codecentric/hikaku/converters/spring/extensions/ProducesSpringExtension.kt b/spring/src/main/kotlin/de/codecentric/hikaku/converters/spring/extensions/ProducesSpringExtension.kt
index fa05c143..efe9c551 100644
--- a/spring/src/main/kotlin/de/codecentric/hikaku/converters/spring/extensions/ProducesSpringExtension.kt
+++ b/spring/src/main/kotlin/de/codecentric/hikaku/converters/spring/extensions/ProducesSpringExtension.kt
@@ -44,14 +44,18 @@ internal fun Map.Entry<RequestMappingInfo, HandlerMethod>.produces(): Set<String
             ?.jvmErasure
             ?.java
 
-    return when(returnType) {
-        java.lang.String::class.java -> setOf(TEXT_PLAIN_VALUE)
-        RedirectView::class.java -> emptySet()
+    return when {
+        returnType == java.lang.String::class.java -> setOf(TEXT_PLAIN_VALUE)
+        returnType == String::class.java -> setOf(TEXT_PLAIN_VALUE)
+        returnType == RedirectView::class.java -> emptySet()
+        returnType != null && isVoid(returnType) -> emptySet()
         else -> setOf(APPLICATION_JSON_VALUE)
     }
 }
 
-private fun Method.hasNoReturnType() = this.returnType.name == "void" || this.returnType.name == "java.lang.Void"
+private fun Method.hasNoReturnType() = isVoid(this.returnType)
+
+private fun isVoid(returnType: Class<*>) = returnType.name == "void" || returnType.name == "java.lang.Void" || returnType.name == "kotlin.Unit"
 
 private fun HandlerMethod.providesRestControllerAnnotation() = this.method
         .kotlinFunction
diff --git a/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/RedirectTestController.kt b/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/RedirectTestController.kt
index 137ced25..7e390445 100644
--- a/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/RedirectTestController.kt
+++ b/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/RedirectTestController.kt
@@ -2,8 +2,10 @@ package de.codecentric.hikaku.converters.spring.produces.redirect
 
 import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.ResponseBody
 import org.springframework.web.bind.annotation.RestController
 import org.springframework.web.servlet.view.RedirectView
+import javax.servlet.http.HttpServletResponse
 
 @SpringBootApplication
 open class DummyApp
@@ -14,3 +16,13 @@ open class RedirectTestController {
     @GetMapping("/todos")
     fun todos(): RedirectView = RedirectView()
 }
+
+@RestController
+open class RedirectUsingHttpServletResponseTestController {
+
+    @GetMapping("/todos")
+    @ResponseBody
+    fun getTest(response: HttpServletResponse) {
+        response.sendRedirect("http://localhost:8080/other")
+    }
+}
diff --git a/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/SpringControllerRedirectTest.kt b/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/SpringControllerRedirectTest.kt
index 81c0782d..266460fa 100644
--- a/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/SpringControllerRedirectTest.kt
+++ b/spring/src/test/kotlin/de/codecentric/hikaku/converters/spring/produces/redirect/SpringControllerRedirectTest.kt
@@ -38,4 +38,28 @@ class SpringControllerRedirectTest {
             assertThat(implementation.conversionResult).containsExactlyInAnyOrderElementsOf(specification)
         }
     }
+
+    @Nested
+    @WebMvcTest(RedirectUsingHttpServletResponseTestController::class, excludeAutoConfiguration = [ErrorMvcAutoConfiguration::class])
+    inner class RedirectUsingHttpServletResponseTest {
+
+        @Autowired
+        lateinit var context: ConfigurableApplicationContext
+
+        @Test
+        fun `produces not set if the return type is RedirectView`() {
+            //given
+            val specification: Set<Endpoint> = setOf(
+                Endpoint("/todos", GET, produces = emptySet()),
+                Endpoint("/todos", HEAD, produces = emptySet()),
+                Endpoint("/todos", OPTIONS, produces = emptySet())
+            )
+
+            //when
+            val implementation = SpringConverter(context)
+
+            //then
+            assertThat(implementation.conversionResult).containsExactlyInAnyOrderElementsOf(specification)
+        }
+    }
 }