Refine null-safety in spring-expression

See gh-32475

Author: sdeleuze

Diff for: spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -463,7 +463,7 @@ public TypeDescriptor getMapValueTypeDescriptor() {
 	 * @see #narrow(Object)
 	 */
 	@Nullable
-	public TypeDescriptor getMapValueTypeDescriptor(Object mapValue) {
+	public TypeDescriptor getMapValueTypeDescriptor(@Nullable Object mapValue) {
 		return narrow(mapValue, getMapValueTypeDescriptor());
 	}
 

Diff for: spring-expression/src/main/java/org/springframework/expression/EvaluationException.java

@@ -16,6 +16,8 @@
 
 package org.springframework.expression;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Represent an exception that occurs during expression evaluation.
  *
@@ -38,7 +40,7 @@ public EvaluationException(String message) {
 	 * @param message description of the problem that occurred
 	 * @param cause the underlying cause of this exception
 	 */
-	public EvaluationException(String message, Throwable cause) {
+	public EvaluationException(String message, @Nullable Throwable cause) {
 		super(message,cause);
 	}
 
@@ -66,7 +68,7 @@ public EvaluationException(String expressionString, String message) {
 	 * @param message description of the problem that occurred
 	 * @param cause the underlying cause of this exception
 	 */
-	public EvaluationException(int position, String message, Throwable cause) {
+	public EvaluationException(int position, String message, @Nullable Throwable cause) {
 		super(position, message, cause);
 	}
 

Diff for: spring-expression/src/main/java/org/springframework/expression/ExpressionException.java

@@ -49,7 +49,7 @@ public ExpressionException(String message) {
 	 * @param message a descriptive message
 	 * @param cause the underlying cause of this exception
 	 */
-	public ExpressionException(String message, Throwable cause) {
+	public ExpressionException(String message, @Nullable Throwable cause) {
 		super(message, cause);
 		this.expressionString = null;
 		this.position = 0;
@@ -95,7 +95,7 @@ public ExpressionException(int position, String message) {
 	 * @param message a descriptive message
 	 * @param cause the underlying cause of this exception
 	 */
-	public ExpressionException(int position, String message, Throwable cause) {
+	public ExpressionException(int position, String message, @Nullable Throwable cause) {
 		super(message, cause);
 		this.expressionString = null;
 		this.position = position;
@@ -124,6 +124,7 @@ public final int getPosition() {
 	 * @see java.lang.Throwable#getMessage()
 	 */
 	@Override
+	@Nullable
 	public String getMessage() {
 		return toDetailedString();
 	}
@@ -132,6 +133,7 @@ public String getMessage() {
 	 * Return a detailed description of this exception, including the expression
 	 * String and position (if available) as well as the actual exception message.
 	 */
+	@Nullable
 	public String toDetailedString() {
 		if (this.expressionString != null) {
 			StringBuilder output = new StringBuilder();
@@ -156,6 +158,7 @@ public String toDetailedString() {
 	 * that caused the failure.
 	 * @since 4.0
 	 */
+	@Nullable
 	public String getSimpleMessage() {
 		return super.getMessage();
 	}

Diff for: spring-expression/src/main/java/org/springframework/expression/ExpressionInvocationTargetException.java

@@ -16,6 +16,8 @@
 
 package org.springframework.expression;
 
+import org.springframework.lang.Nullable;
+
 /**
  * This exception wraps (as cause) a checked exception thrown by some method that SpEL
  * invokes. It differs from a SpelEvaluationException because this indicates the
@@ -28,7 +30,7 @@
 @SuppressWarnings("serial")
 public class ExpressionInvocationTargetException extends EvaluationException {
 
-	public ExpressionInvocationTargetException(int position, String message, Throwable cause) {
+	public ExpressionInvocationTargetException(int position, String message, @Nullable Throwable cause) {
 		super(position, message, cause);
 	}
 
@@ -40,7 +42,7 @@ public ExpressionInvocationTargetException(String expressionString, String messa
 		super(expressionString, message);
 	}
 
-	public ExpressionInvocationTargetException(String message, Throwable cause) {
+	public ExpressionInvocationTargetException(String message, @Nullable Throwable cause) {
 		super(message, cause);
 	}
 

Diff for: spring-expression/src/main/java/org/springframework/expression/spel/InternalParseException.java

@@ -16,6 +16,8 @@
 
 package org.springframework.expression.spel;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Wraps a real parse exception. This exception flows to the top parse method and then
  * the wrapped exception is thrown as the real problem.
@@ -26,11 +28,12 @@
 @SuppressWarnings("serial")
 public class InternalParseException extends RuntimeException {
 
-	public InternalParseException(SpelParseException cause) {
+	public InternalParseException(@Nullable SpelParseException cause) {
 		super(cause);
 	}
 
 	@Override
+	@Nullable
 	public SpelParseException getCause() {
 		return (SpelParseException) super.getCause();
 	}

Diff for: spring-expression/src/main/java/org/springframework/expression/spel/SpelEvaluationException.java

@@ -17,6 +17,7 @@
 package org.springframework.expression.spel;
 
 import org.springframework.expression.EvaluationException;
+import org.springframework.lang.Nullable;
 
 /**
  * Root exception for Spring EL related exceptions.
@@ -35,28 +36,29 @@ public class SpelEvaluationException extends EvaluationException {
 
 	private final SpelMessage message;
 
+	@Nullable
 	private final Object[] inserts;
 
 
-	public SpelEvaluationException(SpelMessage message, Object... inserts) {
+	public SpelEvaluationException(SpelMessage message, @Nullable Object... inserts) {
 		super(message.formatMessage(inserts));
 		this.message = message;
 		this.inserts = inserts;
 	}
 
-	public SpelEvaluationException(int position, SpelMessage message, Object... inserts) {
+	public SpelEvaluationException(int position, SpelMessage message, @Nullable Object... inserts) {
 		super(position, message.formatMessage(inserts));
 		this.message = message;
 		this.inserts = inserts;
 	}
 
-	public SpelEvaluationException(int position, Throwable cause, SpelMessage message, Object... inserts) {
+	public SpelEvaluationException(int position, @Nullable Throwable cause, SpelMessage message, @Nullable Object... inserts) {
 		super(position, message.formatMessage(inserts), cause);
 		this.message = message;
 		this.inserts = inserts;
 	}
 
-	public SpelEvaluationException(Throwable cause, SpelMessage message, Object... inserts) {
+	public SpelEvaluationException(@Nullable Throwable cause, SpelMessage message, @Nullable Object... inserts) {
 		super(message.formatMessage(inserts), cause);
 		this.message = message;
 		this.inserts = inserts;
@@ -80,6 +82,7 @@ public SpelMessage getMessageCode() {
 	/**
 	 * Return the message inserts.
 	 */
+	@Nullable
 	public Object[] getInserts() {
 		return this.inserts;
 	}

Diff for: spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java

@@ -18,6 +18,8 @@
 
 import java.text.MessageFormat;
 
+import org.springframework.lang.Nullable;
+
 /**
  * Contains all the messages that can be produced by the Spring Expression Language.
  *
@@ -313,7 +315,7 @@ public enum SpelMessage {
 	 * @return a formatted message
 	 * @since 4.3.5
 	 */
-	public String formatMessage(Object... inserts) {
+	public String formatMessage(@Nullable Object... inserts) {
 		StringBuilder formattedMessage = new StringBuilder();
 		formattedMessage.append("EL").append(this.code);
 		if (this.kind == Kind.ERROR) {

Diff for: spring-expression/src/main/java/org/springframework/expression/spel/ast/SpelNodeImpl.java

@@ -71,7 +71,7 @@ public abstract class SpelNodeImpl implements SpelNode, Opcodes {
 	protected volatile String exitTypeDescriptor;
 
 
-	public SpelNodeImpl(int startPos, int endPos, SpelNodeImpl... operands) {
+	public SpelNodeImpl(int startPos, int endPos, @Nullable SpelNodeImpl... operands) {
 		this.startPos = startPos;
 		this.endPos = endPos;
 		if (!ObjectUtils.isEmpty(operands)) {