Polish "Set max request header size on Netty when using HTTP/2"

See gh-36766

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/NettyWebServerFactoryCustomizer.java

@@ -66,8 +66,11 @@ public class NettyWebServerFactoryCustomizer
 			.to((idleTimeout) -> customizeIdleTimeout(factory, idleTimeout));
 		propertyMapper.from(nettyProperties::getMaxKeepAliveRequests)
 			.to((maxKeepAliveRequests) -> customizeMaxKeepAliveRequests(factory, maxKeepAliveRequests));
-		propertyMapper.from(this.serverProperties.getMaxHttpRequestHeaderSize())
-			.to((maxHttpRequestHeaderSize) -> customizeHttp2MaxHeaderSize(factory, maxHttpRequestHeaderSize.toBytes()));
+		if (this.serverProperties.getHttp2() != null && this.serverProperties.getHttp2().isEnabled()) {
+			propertyMapper.from(this.serverProperties.getMaxHttpHeaderSize())
+				.whenNonNull()
+				.to((size) -> customizeHttp2MaxHeaderSize(factory, size.toBytes()));
+		}
 		customizeRequestDecoder(factory, propertyMapper);
 	}
 
@@ -120,9 +123,9 @@ public class NettyWebServerFactoryCustomizer
 		factory.addServerCustomizers((httpServer) -> httpServer.maxKeepAliveRequests(maxKeepAliveRequests));
 	}
 
-	private void customizeHttp2MaxHeaderSize(NettyReactiveWebServerFactory factory, long maxHttpRequestHeaderSize) {
-		factory.addServerCustomizers(((httpServer) -> httpServer.http2Settings(
-				(http2SettingsSpecBuilder) -> http2SettingsSpecBuilder.maxHeaderListSize(maxHttpRequestHeaderSize))));
+	private void customizeHttp2MaxHeaderSize(NettyReactiveWebServerFactory factory, long size) {
+		factory.addServerCustomizers(
+				((httpServer) -> httpServer.http2Settings((settings) -> settings.maxHeaderListSize(size))));
 	}
 
 }

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/embedded/NettyWebServerFactoryCustomizerTests.java

@@ -130,6 +130,7 @@ class NettyWebServerFactoryCustomizerTests {
 	@Test
 	void setHttp2MaxRequestHeaderSize() {
 		DataSize headerSize = DataSize.ofKilobytes(24);
+		this.serverProperties.getHttp2().setEnabled(true);
 		this.serverProperties.setMaxHttpHeaderSize(headerSize);
 		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
 		this.customizer.customize(factory);
@@ -147,8 +148,8 @@ class NettyWebServerFactoryCustomizerTests {
 		nettyProperties.setMaxInitialLineLength(DataSize.ofKilobytes(32));
 		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
 		this.customizer.customize(factory);
-		then(factory).should(times(2)).addServerCustomizers(this.customizerCaptor.capture());
-		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(1);
+		then(factory).should().addServerCustomizers(this.customizerCaptor.capture());
+		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(0);
 		HttpServer httpServer = serverCustomizer.apply(HttpServer.create());
 		HttpRequestDecoderSpec decoder = httpServer.configuration().decoder();
 		assertThat(decoder.validateHeaders()).isFalse();
@@ -164,7 +165,7 @@ class NettyWebServerFactoryCustomizerTests {
 			then(factory).should(never()).addServerCustomizers(any(NettyServerCustomizer.class));
 			return;
 		}
-		then(factory).should(times(3)).addServerCustomizers(this.customizerCaptor.capture());
+		then(factory).should(times(2)).addServerCustomizers(this.customizerCaptor.capture());
 		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(0);
 		HttpServer httpServer = serverCustomizer.apply(HttpServer.create());
 		Map<ChannelOption<?>, ?> options = httpServer.configuration().options();
@@ -176,7 +177,7 @@ class NettyWebServerFactoryCustomizerTests {
 			then(factory).should(never()).addServerCustomizers(any(NettyServerCustomizer.class));
 			return;
 		}
-		then(factory).should(times(3)).addServerCustomizers(this.customizerCaptor.capture());
+		then(factory).should(times(2)).addServerCustomizers(this.customizerCaptor.capture());
 		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(0);
 		HttpServer httpServer = serverCustomizer.apply(HttpServer.create());
 		Duration idleTimeout = httpServer.configuration().idleTimeout();
@@ -184,7 +185,7 @@ class NettyWebServerFactoryCustomizerTests {
 	}
 
 	private void verifyMaxKeepAliveRequests(NettyReactiveWebServerFactory factory, int expected) {
-		then(factory).should(times(3)).addServerCustomizers(this.customizerCaptor.capture());
+		then(factory).should(times(2)).addServerCustomizers(this.customizerCaptor.capture());
 		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(0);
 		HttpServer httpServer = serverCustomizer.apply(HttpServer.create());
 		int maxKeepAliveRequests = httpServer.configuration().maxKeepAliveRequests();