Add the enableSpringELCompiler on ThymeleafProperties

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafAutoConfiguration.java

@@ -69,6 +69,7 @@
  * @author Brian Clozel
  * @author Eddú Meléndez
  * @author Daniel Fernández
+ * @author Kazuki Shimizu
  */
 @Configuration
 @EnableConfigurationProperties(ThymeleafProperties.class)
@@ -131,13 +132,16 @@ public SpringResourceTemplateResolver defaultTemplateResolver() {
 	@Configuration
 	protected static class ThymeleafDefaultConfiguration {
 
+		private final ThymeleafProperties properties;
+
 		private final Collection<ITemplateResolver> templateResolvers;
 
 		private final Collection<IDialect> dialects;
 
-		public ThymeleafDefaultConfiguration(
+		public ThymeleafDefaultConfiguration(ThymeleafProperties properties,
 				Collection<ITemplateResolver> templateResolvers,
 				ObjectProvider<Collection<IDialect>> dialectsProvider) {
+			this.properties = properties;
 			this.templateResolvers = templateResolvers;
 			this.dialects = dialectsProvider.getIfAvailable(Collections::emptyList);
 		}
@@ -148,6 +152,7 @@ public SpringTemplateEngine templateEngine() {
 			SpringTemplateEngine engine = new SpringTemplateEngine();
 			this.templateResolvers.forEach(engine::addTemplateResolver);
 			this.dialects.forEach(engine::addDialect);
+			engine.setEnableSpringELCompiler(this.properties.isEnableSpringElCompiler());
 			return engine;
 		}
 
@@ -215,12 +220,16 @@ private String appendCharset(MimeType type, String charset) {
 	@ConditionalOnProperty(name = "spring.thymeleaf.enabled", matchIfMissing = true)
 	static class ThymeleafReactiveConfiguration {
 
+		private final ThymeleafProperties properties;
+
 		private final Collection<ITemplateResolver> templateResolvers;
 
 		private final Collection<IDialect> dialects;
 
-		ThymeleafReactiveConfiguration(Collection<ITemplateResolver> templateResolvers,
+		ThymeleafReactiveConfiguration(ThymeleafProperties properties,
+				Collection<ITemplateResolver> templateResolvers,
 				ObjectProvider<Collection<IDialect>> dialectsProvider) {
+			this.properties = properties;
 			this.templateResolvers = templateResolvers;
 			this.dialects = dialectsProvider.getIfAvailable(Collections::emptyList);
 		}
@@ -231,6 +240,7 @@ public SpringWebFluxTemplateEngine templateEngine() {
 			SpringWebFluxTemplateEngine engine = new SpringWebFluxTemplateEngine();
 			this.templateResolvers.forEach(engine::addTemplateResolver);
 			this.dialects.forEach(engine::addDialect);
+			engine.setEnableSpringELCompiler(this.properties.isEnableSpringElCompiler());
 			return engine;
 		}
 

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafProperties.java

@@ -29,6 +29,7 @@
  * @author Stephane Nicoll
  * @author Brian Clozel
  * @author Daniel Fernández
+ * @author Kazuki Shimizu
  * @since 1.2.0
  */
 @ConfigurationProperties(prefix = "spring.thymeleaf")
@@ -94,6 +95,11 @@ public class ThymeleafProperties {
 	 */
 	private String[] excludedViewNames;
 
+	/**
+	 * Enable the SpringEL compiler in SpringEL expressions.
+	 */
+	private boolean enableSpringElCompiler;
+
 	/**
 	 * Enable Thymeleaf view resolution for Web frameworks.
 	 */
@@ -191,6 +197,14 @@ public void setViewNames(String[] viewNames) {
 		this.viewNames = viewNames;
 	}
 
+	public boolean isEnableSpringElCompiler() {
+		return this.enableSpringElCompiler;
+	}
+
+	public void setEnableSpringElCompiler(boolean enableSpringElCompiler) {
+		this.enableSpringElCompiler = enableSpringElCompiler;
+	}
+
 	public Reactive getReactive() {
 		return this.reactive;
 	}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafReactiveAutoConfigurationTests.java

@@ -28,6 +28,7 @@
 import org.thymeleaf.TemplateEngine;
 import org.thymeleaf.context.Context;
 import org.thymeleaf.spring5.ISpringWebFluxTemplateEngine;
+import org.thymeleaf.spring5.SpringWebFluxTemplateEngine;
 import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver;
 import org.thymeleaf.spring5.view.reactive.ThymeleafReactiveViewResolver;
 import org.thymeleaf.templateresolver.ITemplateResolver;
@@ -51,6 +52,7 @@
  * Tests for {@link ThymeleafAutoConfiguration} in Reactive applications.
  *
  * @author Brian Clozel
+ * @author Kazuki Shimizu
  */
 public class ThymeleafReactiveAutoConfigurationTests {
 
@@ -192,6 +194,18 @@ public void layoutDialectCanBeCustomized() throws Exception {
 				.isInstanceOf(GroupingStrategy.class);
 	}
 
+	@Test
+	public void enableSpringElCompilerCanBeEnabled() {
+		load(BaseConfiguration.class, "spring.thymeleaf.enable-spring-el-compiler:true");
+		assertThat(this.context.getBean(SpringWebFluxTemplateEngine.class).getEnableSpringELCompiler()).isTrue();
+	}
+
+	@Test
+	public void enableSpringElCompilerIsDisabledByDefault() {
+		load(BaseConfiguration.class);
+		assertThat(this.context.getBean(SpringWebFluxTemplateEngine.class).getEnableSpringELCompiler()).isFalse();
+	}
+
 	private void load(Class<?> config, String... envVariables) {
 		this.context = new GenericReactiveWebApplicationContext();
 		TestPropertyValues.of(envVariables).applyTo(this.context);

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/thymeleaf/ThymeleafServletAutoConfigurationTests.java

@@ -27,6 +27,7 @@
 import org.junit.Test;
 import org.thymeleaf.TemplateEngine;
 import org.thymeleaf.context.Context;
+import org.thymeleaf.spring5.SpringTemplateEngine;
 import org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver;
 import org.thymeleaf.spring5.view.ThymeleafView;
 import org.thymeleaf.spring5.view.ThymeleafViewResolver;
@@ -59,6 +60,7 @@
  * @author Stephane Nicoll
  * @author Eddú Meléndez
  * @author Brian Clozel
+ * @author Kazuki Shimizu
  */
 public class ThymeleafServletAutoConfigurationTests {
 
@@ -217,6 +219,18 @@ public void cachingCanBeDisabled() {
 		assertThat(templateResolver.isCacheable()).isFalse();
 	}
 
+	@Test
+	public void enableSpringElCompilerCanBeEnabled() {
+		load(BaseConfiguration.class, "spring.thymeleaf.enable-spring-el-compiler:true");
+		assertThat(this.context.getBean(SpringTemplateEngine.class).getEnableSpringELCompiler()).isTrue();
+	}
+
+	@Test
+	public void enableSpringElCompilerIsDisabledByDefault() {
+		load(BaseConfiguration.class);
+		assertThat(this.context.getBean(SpringTemplateEngine.class).getEnableSpringELCompiler()).isFalse();
+	}
+
 	private void load(Class<?> config, String... envVariables) {
 		this.context = new AnnotationConfigWebApplicationContext();
 		TestPropertyValues.of(envVariables).applyTo(this.context);

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -456,6 +456,7 @@ content into your application; rather pick only the properties that you need.
 	spring.thymeleaf.check-template=true # Check that the template exists before rendering it.
 	spring.thymeleaf.check-template-location=true # Check that the templates location exists.
 	spring.thymeleaf.enabled=true # Enable Thymeleaf view resolution for Web frameworks.
+	spring.thymeleaf.enable-spring-el-compiler=false # Enable the SpringEL compiler in SpringEL expressions.
 	spring.thymeleaf.encoding=UTF-8 # Template files encoding.
 	spring.thymeleaf.excluded-view-names= # Comma-separated list of view names that should be excluded from resolution.
 	spring.thymeleaf.mode=HTML5 # Template mode to be applied to templates. See also StandardTemplateModeHandlers.