Mojarra issue 5190 merged into 4 0

impl/src/main/java/com/sun/faces/el/ELUtils.java

@@ -16,6 +16,7 @@
 package com.sun.faces.el;
 
 import static com.sun.faces.RIConstants.EMPTY_CLASS_ARGS;
+import static com.sun.faces.config.WebConfiguration.BooleanWebContextInitParameter.InterpretEmptyStringSubmittedValuesAsNull;
 import static com.sun.faces.util.MessageUtils.NULL_PARAMETERS_ERROR_MESSAGE_ID;
 import static com.sun.faces.util.MessageUtils.getExceptionMessageString;
 import static com.sun.faces.util.ReflectionUtils.lookupMethod;
@@ -29,6 +30,7 @@
 import java.util.regex.Pattern;
 
 import com.sun.faces.application.ApplicationAssociate;
+import com.sun.faces.config.WebConfiguration;
 import com.sun.faces.context.flash.FlashELResolver;
 
 import jakarta.el.ArrayELResolver;
@@ -111,6 +113,7 @@ public class ELUtils {
     public static final ScopedAttributeELResolver SCOPED_RESOLVER = new ScopedAttributeELResolver();
     public static final ResourceELResolver RESOURCE_RESOLVER = new ResourceELResolver();
     public static final CompositeComponentAttributesELResolver COMPOSITE_COMPONENT_ATTRIBUTES_EL_RESOLVER = new CompositeComponentAttributesELResolver();
+    public static final EmptyStringToNullELResolver EMPTY_STRING_TO_NULL_RESOLVER = new EmptyStringToNullELResolver();
 
     // ------------------------------------------------------------ Constructors
 
@@ -165,6 +168,11 @@ public static void buildFacesResolver(FacesCompositeELResolver composite, Applic
         composite.addPropertyELResolver(COMPOSITE_COMPONENT_ATTRIBUTES_EL_RESOLVER);
         addELResolvers(composite, associate.getELResolversFromFacesConfig());
         composite.add(associate.getApplicationELResolvers());
+
+        if (WebConfiguration.getInstance().isOptionEnabled(InterpretEmptyStringSubmittedValuesAsNull)) {
+            composite.addPropertyELResolver(EMPTY_STRING_TO_NULL_RESOLVER);
+        }
+
         composite.addPropertyELResolver(RESOURCE_RESOLVER);
         composite.addPropertyELResolver(BUNDLE_RESOLVER);
         composite.addRootELResolver(FACES_BUNDLE_RESOLVER);

impl/src/main/java/com/sun/faces/el/EmptyStringToNullELResolver.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 1997, 2022 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package com.sun.faces.el;
+
+import java.beans.FeatureDescriptor;
+import java.util.Iterator;
+
+import jakarta.el.ELContext;
+import jakarta.el.ELResolver;
+
+public class EmptyStringToNullELResolver extends ELResolver {
+
+    @Override
+    public Class<?> getCommonPropertyType(ELContext context, Object base) {
+        return String.class;
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public <T> T convertToType(ELContext context, Object value, Class<T> targetType) {
+        if (value == null && targetType == String.class) {
+            context.setPropertyResolved(true);
+        }
+
+        return (T) value;
+    }
+
+    @Override
+    public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
+        return null;
+    }
+
+    @Override
+    public Class<?> getType(ELContext context, Object base, Object property) {
+        return null;
+    }
+
+    @Override
+    public Object getValue(ELContext context, Object base, Object property) {
+        return null;
+    }
+
+    @Override
+    public boolean isReadOnly(ELContext context, Object base, Object property) {
+        return true;
+    }
+
+    @Override
+    public void setValue(ELContext context, Object base, Object property, Object value) {
+        // NOOP.
+    }
+
+}