The response scheme is erased with the generic void type. Fixes #555.

Author: bnasslahsen

springdoc-openapi-common/src/main/java/org/springdoc/core/GenericResponseBuilder.java

@@ -44,6 +44,7 @@
 import org.apache.commons.lang3.StringUtils;
 
 import org.springframework.core.MethodParameter;
+import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.http.HttpStatus;
 import org.springframework.util.CollectionUtils;
@@ -53,6 +54,7 @@
 import org.springframework.web.method.HandlerMethod;
 
 import static org.springdoc.core.Constants.DEFAULT_DESCRIPTION;
+import static org.springdoc.core.converters.ConverterUtils.isResponseTypeWrapper;
 
 @SuppressWarnings("rawtypes")
 public class GenericResponseBuilder {
@@ -336,7 +338,7 @@ private boolean isVoid(Type returnType) {
 			result = true;
 		else if (returnType instanceof ParameterizedType) {
 			Type[] types = ((ParameterizedType) returnType).getActualTypeArguments();
-			if (types != null)
+			if (types != null && isResponseTypeWrapper(ResolvableType.forType(returnType).getRawClass()))
 				return isVoid(types[0]);
 		}
 		if (Void.class.equals(returnType))

springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/app108/ActionResult.java

@@ -0,0 +1,59 @@
+package test.org.springdoc.api.app108;
+
+public class ActionResult<T> {
+
+	protected T value;
+	protected boolean success;
+	protected String errorCode;
+	protected String message;
+	protected Object errorValue;
+	protected String targetUrl;
+
+	public T getValue() {
+		return value;
+	}
+
+	public void setValue(T value) {
+		this.value = value;
+	}
+
+	public boolean isSuccess() {
+		return success;
+	}
+
+	public void setSuccess(boolean success) {
+		this.success = success;
+	}
+
+	public String getErrorCode() {
+		return errorCode;
+	}
+
+	public void setErrorCode(String errorCode) {
+		this.errorCode = errorCode;
+	}
+
+	public String getMessage() {
+		return message;
+	}
+
+	public void setMessage(String message) {
+		this.message = message;
+	}
+
+	public Object getErrorValue() {
+		return errorValue;
+	}
+
+	public void setErrorValue(Object errorValue) {
+		this.errorValue = errorValue;
+	}
+
+	public String getTargetUrl() {
+		return targetUrl;
+	}
+
+	public void setTargetUrl(String targetUrl) {
+		this.targetUrl = targetUrl;
+	}
+}

springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/app108/HelloController.java

@@ -0,0 +1,14 @@
+package test.org.springdoc.api.app108;
+
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HelloController {
+
+	@PostMapping
+	public ActionResult<Void> update(String toto) {
+		return null;
+	}
+}
+

springdoc-openapi-webmvc-core/src/test/java/test/org/springdoc/api/app108/SpringDocApp108Test.java

@@ -0,0 +1,10 @@
+package test.org.springdoc.api.app108;
+
+import test.org.springdoc.api.AbstractSpringDocTest;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+public class SpringDocApp108Test extends AbstractSpringDocTest {
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+}

springdoc-openapi-webmvc-core/src/test/resources/results/app108.json

@@ -0,0 +1,71 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/": {
+      "post": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "update",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "string"
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "default response",
+            "content": {
+              "*/*": {
+                "schema": {
+                  "$ref": "#/components/schemas/ActionResultVoid"
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "ActionResultVoid": {
+        "type": "object",
+        "properties": {
+          "value": {
+            "type": "object"
+          },
+          "success": {
+            "type": "boolean"
+          },
+          "errorCode": {
+            "type": "string"
+          },
+          "message": {
+            "type": "string"
+          },
+          "errorValue": {
+            "type": "object"
+          },
+          "targetUrl": {
+            "type": "string"
+          }
+        }
+      }
+    }
+  }
+}