NPEs when using @ParameterObject with custom Pageable and adding descriptions to fields. Fixes springdoc#1333

Author: bnasslahsen

springdoc-openapi-data-rest/src/main/java/org/springdoc/data/rest/customisers/DataRestDelegatingMethodParameterCustomizer.java

@@ -24,7 +24,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springdoc.core.DelegatingMethodParameter;
-import org.springdoc.core.converters.models.Pageable;
 import org.springdoc.core.customizers.DelegatingMethodParameterCustomizer;
 
 import org.springframework.boot.autoconfigure.data.web.SpringDataWebProperties;
@@ -72,8 +71,11 @@ public void customize(MethodParameter originalParameter, MethodParameter methodP
 				Annotation[] parameterAnnotations = (Annotation[]) field.get(methodParameter);
 				if (ArrayUtils.isNotEmpty(parameterAnnotations))
 					for (int i = 0; i < parameterAnnotations.length; i++) {
-						if (Parameter.class.equals(parameterAnnotations[i].annotationType()))
-							parameterAnnotations[i] = getNewParameterAnnotationForField(methodParameter.getParameterName(), pageableDefault);
+						if (Parameter.class.equals(parameterAnnotations[i].annotationType())){
+							Optional<Annotation> annotationForField	 = getNewParameterAnnotationForField(methodParameter, pageableDefault);
+							if(annotationForField.isPresent())
+								parameterAnnotations[i] = annotationForField.get();
+						}
 					}
 			}
 			catch (IllegalAccessException e) {
@@ -85,15 +87,16 @@ public void customize(MethodParameter originalParameter, MethodParameter methodP
 	/**
 	 * Gets new parameter annotation for field.
 	 *
-	 * @param parameterName the parameter name
+	 * @param methodParameter the method parameter
 	 * @param pageableDefault the pageable default
 	 * @return the new parameter annotation for field
 	 */
-	private Annotation getNewParameterAnnotationForField(String parameterName, PageableDefault pageableDefault) {
+	private Optional<Annotation> getNewParameterAnnotationForField(MethodParameter methodParameter, PageableDefault pageableDefault) {
+		String parameterName = methodParameter.getParameterName();
 		Field field;
-		Parameter parameterNew = null;
+		Parameter parameterNew;
 		try {
-			field = Pageable.class.getDeclaredField(parameterName);
+			field = methodParameter.getContainingClass().getDeclaredField(parameterName);
 			Parameter parameter = field.getAnnotation(Parameter.class);
 			parameterNew = new Parameter() {
 				@Override
@@ -615,11 +618,12 @@ public String ref() {
 					return parameter.ref();
 				}
 			};
+			return Optional.of(parameterNew);
 		}
 		catch (NoSuchFieldException e) {
 			LOGGER.warn(e.getMessage());
+			return Optional.empty();
 		}
-		return parameterNew;
 	}
 
 	/**

springdoc-openapi-data-rest/src/test/java/test/org/springdoc/api/app28/ExamplePageable.java

@@ -0,0 +1,59 @@
+package test.org.springdoc.api.app28;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+import io.swagger.v3.oas.annotations.Parameter;
+
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+
+public class ExamplePageable implements Pageable {
+
+	@Parameter(description = "Anything")
+	@JsonProperty
+	private int something;
+
+	@Override
+	public int getPageNumber() {
+		return 0;
+	}
+
+	@Override
+	public int getPageSize() {
+		return 0;
+	}
+
+	@Override
+	public long getOffset() {
+		return 0;
+	}
+
+	@Override
+	public Sort getSort() {
+		return null;
+	}
+
+	@Override
+	public Pageable next() {
+		return null;
+	}
+
+	@Override
+	public Pageable previousOrFirst() {
+		return null;
+	}
+
+	@Override
+	public Pageable first() {
+		return null;
+	}
+
+	@Override
+	public Pageable withPage(int pageNumber) {
+		return null;
+	}
+
+	@Override
+	public boolean hasPrevious() {
+		return false;
+	}
+}

springdoc-openapi-data-rest/src/test/java/test/org/springdoc/api/app28/ExamplePageableReplacement.java

@@ -0,0 +1,30 @@
+package test.org.springdoc.api.app28;
+
+import java.util.List;
+
+import io.swagger.v3.oas.annotations.Parameter;
+import org.springdoc.core.converters.models.Pageable;
+
+public class ExamplePageableReplacement extends Pageable {
+
+	@Parameter(description = "Anything")
+	private int something;
+
+	/**
+	 * Instantiates a new Pageable.
+	 *  @param page the page
+	 * @param size the size
+	 * @param sort the sort
+	 */
+	public ExamplePageableReplacement(int page, int size, List<String> sort) {
+		super(page, size, sort);
+	}
+
+	public int getSomething() {
+		return something;
+	}
+
+	public void setSomething(int something) {
+		this.something = something;
+	}
+}

springdoc-openapi-data-rest/src/test/java/test/org/springdoc/api/app28/HelloController.java

@@ -0,0 +1,21 @@
+package test.org.springdoc.api.app28;
+
+import org.springdoc.api.annotations.ParameterObject;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * @author bnasslahsen
+ */
+@RestController
+@RequestMapping("/api")
+public class HelloController {
+
+
+	@GetMapping("/items/nested")
+	public void showNestedItem(@ParameterObject ExamplePageable examplePageable) {
+	}
+
+}

springdoc-openapi-data-rest/src/test/java/test/org/springdoc/api/app28/SpringDocApp28Test.java

@@ -0,0 +1,34 @@
+/*
+ *
+ *  * Copyright 2019-2020 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
+ *  *
+ *  *      https://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 test.org.springdoc.api.app28;
+
+import org.springdoc.core.SpringDocUtils;
+import test.org.springdoc.api.AbstractSpringDocTest;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+public class SpringDocApp28Test extends AbstractSpringDocTest {
+
+	@SpringBootApplication
+	static class SpringDocTestApp {}
+
+	static {
+		SpringDocUtils.getConfig().replaceParameterObjectWithClass(ExamplePageable.class, ExamplePageableReplacement.class);
+	}
+}

springdoc-openapi-data-rest/src/test/resources/results/app28.json

@@ -0,0 +1,77 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "paths": {
+    "/api/items/nested": {
+      "get": {
+        "tags": [
+          "hello-controller"
+        ],
+        "operationId": "showNestedItem",
+        "parameters": [
+          {
+            "name": "something",
+            "in": "query",
+            "description": "Anything",
+            "required": false,
+            "schema": {
+              "type": "integer",
+              "format": "int32"
+            }
+          },
+          {
+            "name": "page",
+            "in": "query",
+            "description": "Zero-based page index (0..N)",
+            "required": false,
+            "schema": {
+              "minimum": 0,
+              "type": "integer",
+              "default": 0
+            }
+          },
+          {
+            "name": "size",
+            "in": "query",
+            "description": "The size of the page to be returned",
+            "required": false,
+            "schema": {
+              "minimum": 1,
+              "type": "integer",
+              "default": 20
+            }
+          },
+          {
+            "name": "sort",
+            "in": "query",
+            "description": "Sorting criteria in the format: property(,asc|desc). Default sort order is ascending. Multiple sort criteria are supported.",
+            "required": false,
+            "schema": {
+              "type": "array",
+              "items": {
+                "type": "string"
+              }
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {}
+  }
+}