missingAfterConversion flag for missing request values

Closes spring-projectsgh-26679

spring-web/src/main/java/org/springframework/web/bind/MissingMatrixVariableException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -28,7 +28,7 @@
  * @see MissingPathVariableException
  */
 @SuppressWarnings("serial")
-public class MissingMatrixVariableException extends ServletRequestBindingException {
+public class MissingMatrixVariableException extends MissingRequestValueException {
 
 	private final String variableName;
 
@@ -41,16 +41,30 @@ public class MissingMatrixVariableException extends ServletRequestBindingExcepti
 	 * @param parameter the method parameter
 	 */
 	public MissingMatrixVariableException(String variableName, MethodParameter parameter) {
-		super("");
+		this(variableName, parameter, false);
+	}
+
+	/**
+	 * Constructor for use when a value was present but converted to {@code null}.
+	 * @param variableName the name of the missing matrix variable
+	 * @param parameter the method parameter
+	 * @param missingAfterConversion whether the value became null after conversion
+	 * @since 5.3.6
+	 */
+	public MissingMatrixVariableException(
+			String variableName, MethodParameter parameter, boolean missingAfterConversion) {
+
+		super("", missingAfterConversion);
 		this.variableName = variableName;
 		this.parameter = parameter;
 	}
 
 
 	@Override
 	public String getMessage() {
-		return "Missing matrix variable '" + this.variableName +
-				"' for method parameter of type " + this.parameter.getNestedParameterType().getSimpleName();
+		return "Required matrix variable '" + this.variableName + "' for method parameter type " +
+				this.parameter.getNestedParameterType().getSimpleName() + " is " +
+				(isMissingAfterConversion() ? "present but converted to null" : "not present");
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/bind/MissingPathVariableException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -30,7 +30,7 @@
  * @see MissingMatrixVariableException
  */
 @SuppressWarnings("serial")
-public class MissingPathVariableException extends ServletRequestBindingException {
+public class MissingPathVariableException extends MissingRequestValueException {
 
 	private final String variableName;
 
@@ -43,16 +43,30 @@ public class MissingPathVariableException extends ServletRequestBindingException
 	 * @param parameter the method parameter
 	 */
 	public MissingPathVariableException(String variableName, MethodParameter parameter) {
-		super("");
+		this(variableName, parameter, false);
+	}
+
+	/**
+	 * Constructor for use when a value was present but converted to {@code null}.
+	 * @param variableName the name of the missing path variable
+	 * @param parameter the method parameter
+	 * @param missingAfterConversion whether the value became null after conversion
+	 * @since 5.3.6
+	 */
+	public MissingPathVariableException(
+			String variableName, MethodParameter parameter, boolean missingAfterConversion) {
+
+		super("", missingAfterConversion);
 		this.variableName = variableName;
 		this.parameter = parameter;
 	}
 
 
 	@Override
 	public String getMessage() {
-		return "Missing URI template variable '" + this.variableName +
-				"' for method parameter of type " + this.parameter.getNestedParameterType().getSimpleName();
+		return "Required URI template variable '" + this.variableName + "' for method parameter type " +
+				this.parameter.getNestedParameterType().getSimpleName() + " is " +
+				(isMissingAfterConversion() ? "present but converted to null" : "not present");
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/bind/MissingRequestCookieException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -28,7 +28,7 @@
  * @see MissingRequestHeaderException
  */
 @SuppressWarnings("serial")
-public class MissingRequestCookieException extends ServletRequestBindingException {
+public class MissingRequestCookieException extends MissingRequestValueException {
 
 	private final String cookieName;
 
@@ -41,16 +41,30 @@ public class MissingRequestCookieException extends ServletRequestBindingExceptio
 	 * @param parameter the method parameter
 	 */
 	public MissingRequestCookieException(String cookieName, MethodParameter parameter) {
-		super("");
+		this(cookieName, parameter, false);
+	}
+
+	/**
+	 * Constructor for use when a value was present but converted to {@code null}.
+	 * @param cookieName the name of the missing request cookie
+	 * @param parameter the method parameter
+	 * @param missingAfterConversion whether the value became null after conversion
+	 * @since 5.3.6
+	 */
+	public MissingRequestCookieException(
+			String cookieName, MethodParameter parameter, boolean missingAfterConversion) {
+
+		super("", missingAfterConversion);
 		this.cookieName = cookieName;
 		this.parameter = parameter;
 	}
 
 
 	@Override
 	public String getMessage() {
-		return "Missing cookie '" + this.cookieName +
-				"' for method parameter of type " + this.parameter.getNestedParameterType().getSimpleName();
+		return "Required cookie '" + this.cookieName + "' for method parameter type " +
+				this.parameter.getNestedParameterType().getSimpleName() + " is " +
+				(isMissingAfterConversion() ? "present but converted to null" : "not present");
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/bind/MissingRequestHeaderException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -28,7 +28,7 @@
  * @see MissingRequestCookieException
  */
 @SuppressWarnings("serial")
-public class MissingRequestHeaderException extends ServletRequestBindingException {
+public class MissingRequestHeaderException extends MissingRequestValueException {
 
 	private final String headerName;
 
@@ -41,16 +41,30 @@ public class MissingRequestHeaderException extends ServletRequestBindingExceptio
 	 * @param parameter the method parameter
 	 */
 	public MissingRequestHeaderException(String headerName, MethodParameter parameter) {
-		super("");
+		this(headerName, parameter, false);
+	}
+
+	/**
+	 * Constructor for use when a value was present but converted to {@code null}.
+	 * @param headerName the name of the missing request header
+	 * @param parameter the method parameter
+	 * @param missingAfterConversion whether the value became null after conversion
+	 * @since 5.3.6
+	 */
+	public MissingRequestHeaderException(
+			String headerName, MethodParameter parameter, boolean missingAfterConversion) {
+
+		super("", missingAfterConversion);
 		this.headerName = headerName;
 		this.parameter = parameter;
 	}
 
 
 	@Override
 	public String getMessage() {
-		return "Missing request header '" + this.headerName +
-				"' for method parameter of type " + this.parameter.getNestedParameterType().getSimpleName();
+		String typeName = this.parameter.getNestedParameterType().getSimpleName();
+		return "Required request header '" + this.headerName + "' for method parameter type " + typeName + " is " +
+				(isMissingAfterConversion() ? "present but converted to null" : "not present");
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/bind/MissingRequestValueException.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2002-2021 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 org.springframework.web.bind;
+
+/**
+ * Base class for {@link ServletRequestBindingException} exceptions that could
+ * not bind because the request value is required but is either missing or
+ * otherwise resolves to {@code null} after conversion.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.3.6
+ */
+@SuppressWarnings("serial")
+public class MissingRequestValueException extends ServletRequestBindingException {
+
+	private final boolean missingAfterConversion;
+
+
+	public MissingRequestValueException(String msg) {
+		this(msg, false);
+	}
+
+	public MissingRequestValueException(String msg, boolean missingAfterConversion) {
+		super(msg);
+		this.missingAfterConversion = missingAfterConversion;
+	}
+
+
+	/**
+	 * Whether the request value was present but converted to {@code null}, e.g. via
+	 * {@code org.springframework.core.convert.support.IdToEntityConverter}.
+	 */
+	public boolean isMissingAfterConversion() {
+		return this.missingAfterConversion;
+	}
+
+}

spring-web/src/main/java/org/springframework/web/bind/MissingServletRequestParameterException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -23,7 +23,7 @@
  * @since 2.0.2
  */
 @SuppressWarnings("serial")
-public class MissingServletRequestParameterException extends ServletRequestBindingException {
+public class MissingServletRequestParameterException extends MissingRequestValueException {
 
 	private final String parameterName;
 
@@ -36,15 +36,30 @@ public class MissingServletRequestParameterException extends ServletRequestBindi
 	 * @param parameterType the expected type of the missing parameter
 	 */
 	public MissingServletRequestParameterException(String parameterName, String parameterType) {
-		super("");
+		this(parameterName, parameterType, false);
+	}
+
+	/**
+	 * Constructor for use when a value was present but converted to {@code null}.
+	 * @param parameterName the name of the missing parameter
+	 * @param parameterType the expected type of the missing parameter
+	 * @param missingAfterConversion whether the value became null after conversion
+	 * @since 5.3.6
+	 */
+	public MissingServletRequestParameterException(
+			String parameterName, String parameterType, boolean missingAfterConversion) {
+
+		super("", missingAfterConversion);
 		this.parameterName = parameterName;
 		this.parameterType = parameterType;
 	}
 
 
 	@Override
 	public String getMessage() {
-		return "Required " + this.parameterType + " parameter '" + this.parameterName + "' is not present";
+		return "Required request parameter '" + this.parameterName + "' for method parameter type " +
+				this.parameterType + " is " +
+				(isMissingAfterConversion() ? "present but converted to null" : "not present");
 	}
 
 	/**

spring-web/src/main/java/org/springframework/web/method/annotation/AbstractCookieValueMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -24,6 +24,7 @@
 import org.springframework.web.bind.ServletRequestBindingException;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.CookieValue;
+import org.springframework.web.context.request.NativeWebRequest;
 
 /**
  * A base abstract class to resolve method arguments annotated with
@@ -70,6 +71,12 @@ protected void handleMissingValue(String name, MethodParameter parameter) throws
 		throw new MissingRequestCookieException(name, parameter);
 	}
 
+	@Override
+	protected void handleMissingValueAfterConversion(
+			String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
+
+		throw new MissingRequestCookieException(name, parameter, true);
+	}
 
 	private static final class CookieValueNamedValueInfo extends NamedValueInfo {
 

spring-web/src/main/java/org/springframework/web/method/annotation/AbstractNamedValueMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -135,7 +135,7 @@ else if ("".equals(arg) && namedValueInfo.defaultValue != null) {
 			// Check for null value after conversion of incoming argument value
 			if (arg == null && namedValueInfo.defaultValue == null &&
 					namedValueInfo.required && !nestedParameter.isOptional()) {
-				handleMissingValue(namedValueInfo.name, nestedParameter, webRequest);
+				handleMissingValueAfterConversion(namedValueInfo.name, nestedParameter, webRequest);
 			}
 		}
 
@@ -237,6 +237,19 @@ protected void handleMissingValue(String name, MethodParameter parameter) throws
 				"' for method parameter of type " + parameter.getNestedParameterType().getSimpleName());
 	}
 
+	/**
+	 * Invoked when a named value is present but becomes {@code null} after conversion.
+	 * @param name the name for the value
+	 * @param parameter the method parameter
+	 * @param request the current request
+	 * @since 5.3.6
+	 */
+	protected void handleMissingValueAfterConversion(String name, MethodParameter parameter, NativeWebRequest request)
+			throws Exception {
+
+		handleMissingValue(name, parameter, request);
+	}
+
 	/**
 	 * A {@code null} results in a {@code false} value for {@code boolean}s or an exception for other primitives.
 	 */

spring-web/src/main/java/org/springframework/web/method/annotation/RequestHeaderMethodArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 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.
@@ -87,6 +87,12 @@ protected void handleMissingValue(String name, MethodParameter parameter) throws
 		throw new MissingRequestHeaderException(name, parameter);
 	}
 
+	@Override
+	protected void handleMissingValueAfterConversion(
+			String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
+
+		throw new MissingRequestHeaderException(name, parameter, true);
+	}
 
 	private static final class RequestHeaderNamedValueInfo extends NamedValueInfo {