Merge branch '5.3.x' into main

spring-web/src/main/java/org/springframework/http/server/reactive/AbstractListenerReadPublisher.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,8 @@ import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
 import reactor.core.publisher.Operators;
 
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DefaultDataBufferFactory;
 import org.springframework.core.log.LogDelegateFactory;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -56,6 +58,8 @@ public abstract class AbstractListenerReadPublisher<T> implements Publisher<T> {
 	 */
 	protected static Log rsReadLogger = LogDelegateFactory.getHiddenLog(AbstractListenerReadPublisher.class);
 
+	final static DataBuffer EMPTY_BUFFER = DefaultDataBufferFactory.sharedInstance.allocateBuffer(0);
+
 
 	private final AtomicReference<State> state = new AtomicReference<>(State.UNSUBSCRIBED);
 
@@ -180,7 +184,7 @@ public abstract class AbstractListenerReadPublisher<T> implements Publisher<T> {
 
 	/**
 	 * Read and publish data one at a time until there is no more data, no more
-	 * demand, or perhaps we completed in the mean time.
+	 * demand, or perhaps we completed meanwhile.
 	 * @return {@code true} if there is more demand; {@code false} if there is
 	 * no more demand or we have completed.
 	 */
@@ -188,7 +192,12 @@ public abstract class AbstractListenerReadPublisher<T> implements Publisher<T> {
 		long r;
 		while ((r = this.demand) > 0 && (this.state.get() != State.COMPLETED)) {
 			T data = read();
-			if (data != null) {
+			if (data == EMPTY_BUFFER) {
+				if (rsReadLogger.isTraceEnabled()) {
+					rsReadLogger.trace(getLogPrefix() + "0 bytes read, trying again");
+				}
+			}
+			else if (data != null) {
 				if (r != Long.MAX_VALUE) {
 					DEMAND_FIELD_UPDATER.addAndGet(this, -1L);
 				}

spring-web/src/main/java/org/springframework/http/server/reactive/ServletServerHttpRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -241,10 +241,10 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 	/**
 	 * Read from the request body InputStream and return a DataBuffer.
 	 * Invoked only when {@link ServletInputStream#isReady()} returns "true".
-	 * @return a DataBuffer with data read, or {@link #EOF_BUFFER} if the input
-	 * stream returned -1, or null if 0 bytes were read.
+	 * @return a DataBuffer with data read, or
+	 * {@link AbstractListenerReadPublisher#EMPTY_BUFFER} if 0 bytes were read,
+	 * or {@link #EOF_BUFFER} if the input stream returned -1.
 	 */
-	@Nullable
 	DataBuffer readFromInputStream() throws IOException {
 		int read = this.request.getInputStream().read(this.buffer);
 		logBytesRead(read);
@@ -259,7 +259,7 @@ class ServletServerHttpRequest extends AbstractServerHttpRequest {
 			return EOF_BUFFER;
 		}
 
-		return null;
+		return AbstractListenerReadPublisher.EMPTY_BUFFER;
 	}
 
 	protected final void logBytesRead(int read) {

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/MultipartIntegrationTests.java

@@ -25,7 +25,6 @@ import java.util.stream.Collectors;
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
-import org.junit.jupiter.api.Disabled;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
@@ -63,7 +62,6 @@ import org.springframework.web.testfixture.http.server.reactive.bootstrap.Undert
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assumptions.assumeFalse;
 
-@Disabled
 class MultipartIntegrationTests extends AbstractHttpHandlerIntegrationTests {
 
 	private WebClient webClient;

spring-webflux/src/test/kotlin/org/springframework/web/reactive/result/method/annotation/CoroutinesIntegrationTests.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,7 +25,6 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatExceptionOfType
-import org.junit.jupiter.api.Disabled
 import org.springframework.context.ApplicationContext
 import org.springframework.context.annotation.AnnotationConfigApplicationContext
 import org.springframework.context.annotation.ComponentScan
@@ -41,7 +40,6 @@ import org.springframework.web.testfixture.http.server.reactive.bootstrap.HttpSe
 import reactor.core.publisher.Flux
 import java.time.Duration
 
-@Disabled
 class CoroutinesIntegrationTests : AbstractRequestMappingIntegrationTests() {
 
 	override fun initApplicationContext(): ApplicationContext {