SelectTag consistently checks specified 'multiple' attribute now, never falling back to forceMultiple in case of user-provided value

Issue: SPR-11903

spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/SelectTag.java

@@ -84,7 +84,7 @@ public class SelectTag extends AbstractHtmlInputElementTag {
 	 * Indicates whether or not the '{@code select}' tag allows
 	 * multiple-selections.
 	 */
-	private Object multiple = Boolean.FALSE;
+	private Object multiple;
 
 	/**
 	 * The {@link TagWriter} instance that the output is being written.
@@ -249,9 +249,9 @@ public class SelectTag extends AbstractHtmlInputElementTag {
 
 	private boolean isMultiple() throws JspException {
 		Object multiple = getMultiple();
-		if (multiple != null && (Boolean.TRUE.equals(multiple) ||
-				Boolean.parseBoolean(multiple.toString()) || "multiple".equals(multiple))) {
-			return true;
+		if (multiple != null) {
+			String stringValue = multiple.toString();
+			return ("multiple".equalsIgnoreCase(stringValue) || Boolean.parseBoolean(stringValue));
 		}
 		return forceMultiple();
 	}

spring-webmvc/src/test/java/org/springframework/web/servlet/tags/form/SelectTagTests.java

@@ -256,6 +256,7 @@ public class SelectTagTests extends AbstractFormTagTests {
 		assertTrue(output.startsWith("<select "));
 		assertTrue(output.endsWith("</select>"));
 		assertFalse(output.contains("selected=\"selected\""));
+		assertFalse(output.contains("multiple=\"multiple\""));
 	}
 
 	public void testNestedPathWithListAndEditor() throws Exception {
@@ -731,7 +732,7 @@ public class SelectTagTests extends AbstractFormTagTests {
 		}
 	}
 
-	public void testMultiForCollection() throws Exception {
+	public void testMultipleForCollection() throws Exception {
 		this.bean.setSomeList(new ArrayList());
 
 		this.tag.setPath("someList");
@@ -760,7 +761,35 @@ public class SelectTagTests extends AbstractFormTagTests {
 		assertNotNull(inputElement);
 	}
 
-	public void testMultiExplicit() throws Exception {
+	public void testMultipleWithStringValue() throws Exception {
+		this.tag.setPath("name");
+		this.tag.setItems(Country.getCountries());
+		this.tag.setItemValue("isoCode");
+		this.tag.setMultiple("multiple");
+		int result = this.tag.doStartTag();
+		assertEquals(Tag.SKIP_BODY, result);
+
+		String output = getOutput();
+		output = "<doc>" + output + "</doc>";
+
+		SAXReader reader = new SAXReader();
+		Document document = reader.read(new StringReader(output));
+		Element rootElement = document.getRootElement();
+		assertEquals(2, rootElement.elements().size());
+
+		Element selectElement = rootElement.element("select");
+		assertEquals("select", selectElement.getName());
+		assertEquals("name", selectElement.attribute("name").getValue());
+		assertEquals("multiple", selectElement.attribute("multiple").getValue());
+
+		List children = selectElement.elements();
+		assertEquals("Incorrect number of children", 4, children.size());
+
+		Element inputElement = rootElement.element("input");
+		assertNotNull(inputElement);
+	}
+
+	public void testMultipleExplicitlyTrue() throws Exception {
 		this.tag.setPath("name");
 		this.tag.setItems(Country.getCountries());
 		this.tag.setItemValue("isoCode");
@@ -788,6 +817,84 @@ public class SelectTagTests extends AbstractFormTagTests {
 		assertNotNull(inputElement);
 	}
 
+	public void testMultipleExplicitlyFalse() throws Exception {
+		this.tag.setPath("name");
+		this.tag.setItems(Country.getCountries());
+		this.tag.setItemValue("isoCode");
+		this.tag.setMultiple("false");
+		int result = this.tag.doStartTag();
+		assertEquals(Tag.SKIP_BODY, result);
+
+		String output = getOutput();
+		output = "<doc>" + output + "</doc>";
+
+		SAXReader reader = new SAXReader();
+		Document document = reader.read(new StringReader(output));
+		Element rootElement = document.getRootElement();
+		assertEquals(1, rootElement.elements().size());
+
+		Element selectElement = rootElement.element("select");
+		assertEquals("select", selectElement.getName());
+		assertEquals("name", selectElement.attribute("name").getValue());
+		assertNull(selectElement.attribute("multiple"));
+
+		List children = selectElement.elements();
+		assertEquals("Incorrect number of children", 4, children.size());
+	}
+
+	public void testMultipleWithBooleanTrue() throws Exception {
+		this.tag.setPath("name");
+		this.tag.setItems(Country.getCountries());
+		this.tag.setItemValue("isoCode");
+		this.tag.setMultiple(true);
+		int result = this.tag.doStartTag();
+		assertEquals(Tag.SKIP_BODY, result);
+
+		String output = getOutput();
+		output = "<doc>" + output + "</doc>";
+
+		SAXReader reader = new SAXReader();
+		Document document = reader.read(new StringReader(output));
+		Element rootElement = document.getRootElement();
+		assertEquals(2, rootElement.elements().size());
+
+		Element selectElement = rootElement.element("select");
+		assertEquals("select", selectElement.getName());
+		assertEquals("name", selectElement.attribute("name").getValue());
+		assertEquals("multiple", selectElement.attribute("multiple").getValue());
+
+		List children = selectElement.elements();
+		assertEquals("Incorrect number of children", 4, children.size());
+
+		Element inputElement = rootElement.element("input");
+		assertNotNull(inputElement);
+	}
+
+	public void testMultipleWithBooleanFalse() throws Exception {
+		this.tag.setPath("name");
+		this.tag.setItems(Country.getCountries());
+		this.tag.setItemValue("isoCode");
+		this.tag.setMultiple(false);
+		int result = this.tag.doStartTag();
+		assertEquals(Tag.SKIP_BODY, result);
+
+		String output = getOutput();
+		output = "<doc>" + output + "</doc>";
+
+		SAXReader reader = new SAXReader();
+		Document document = reader.read(new StringReader(output));
+		Element rootElement = document.getRootElement();
+		assertEquals(1, rootElement.elements().size());
+
+		Element selectElement = rootElement.element("select");
+		assertEquals("select", selectElement.getName());
+		assertEquals("name", selectElement.attribute("name").getValue());
+		assertNull(selectElement.attribute("multiple"));
+
+		List children = selectElement.elements();
+		assertEquals("Incorrect number of children", 4, children.size());
+	}
+
 
 	private void assertStringArray() throws JspException, DocumentException {
 		int result = this.tag.doStartTag();