Update to reactor core 3.1.0.B-S with context update for monoSendOperator

Explicit typing for older jvm compilation in BodyExtractor

build.gradle

@@ -83,7 +83,7 @@ configure(allprojects) { project ->
 	ext.poiVersion             = "3.16"
 	ext.protobufVersion        = "3.3.1"
 	ext.quartzVersion          = "2.3.0"
-	ext.reactorVersion         = "Bismuth-M2"
+	ext.reactorVersion         = "Bismuth-BUILD-SNAPSHOT"
 	ext.romeVersion            = "1.7.3"
 	ext.rxjavaVersion          = '1.3.0'
 	ext.rxjavaAdapterVersion   = '1.2.1'
@@ -176,6 +176,7 @@ configure(allprojects) { project ->
 	repositories {
 		maven { url "https://repo.spring.io/libs-release" }
 		maven { url "https://repo.spring.io/milestone" }
+		maven { url "https://repo.spring.io/snapshot" }
 	}
 
 	dependencies {

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

@@ -21,9 +21,13 @@ import java.util.function.Function;
 import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscriber;
 import org.reactivestreams.Subscription;
-import reactor.core.publisher.MonoSource;
+import reactor.core.Scannable;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
 import reactor.core.publisher.Operators;
+import reactor.util.context.Context;
 
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -38,20 +42,30 @@ import org.springframework.util.Assert;
  * @author Stephane Maldini
  * @since 5.0
  */
-public class ChannelSendOperator<T> extends MonoSource<T, Void> {
+public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 
 	private final Function<Publisher<T>, Publisher<Void>> writeFunction;
+	private final Flux<T>                                 source;
 
 
 	public ChannelSendOperator(Publisher<? extends T> source, Function<Publisher<T>, Publisher<Void>> writeFunction) {
-		super(source);
+		this.source = Flux.from(source);
 		this.writeFunction = writeFunction;
 	}
 
+	@Override
+	@Nullable
+	@SuppressWarnings("rawtypes")
+	public Object scanUnsafe(Attr key) {
+		if (key == IntAttr.PREFETCH) return Integer.MAX_VALUE;
+		if (key == ScannableAttr.PARENT) return source;
+		return null;
+	}
+
 
 	@Override
-	public void subscribe(Subscriber<? super Void> s) {
-		this.source.subscribe(new WriteWithBarrier(s));
+	public void subscribe(Subscriber<? super Void> s, Context ctx) {
+		this.source.subscribe(new WriteWithBarrier(s), ctx);
 	}
 
 

spring-webflux/src/main/java/org/springframework/web/reactive/function/BodyExtractors.java

@@ -93,7 +93,7 @@ public abstract class BodyExtractors {
 		Assert.notNull(elementType, "'elementType' must not be null");
 		return (inputMessage, context) -> readWithMessageReaders(inputMessage, context,
 				elementType,
-				reader -> {
+				(HttpMessageReader<T> reader) -> {
 					Optional<ServerHttpResponse> serverResponse = context.serverResponse();
 					if (serverResponse.isPresent() && inputMessage instanceof ServerHttpRequest) {
 						return reader.readMono(elementType, elementType, (ServerHttpRequest) inputMessage,
@@ -142,7 +142,7 @@ public abstract class BodyExtractors {
 		Assert.notNull(elementType, "'elementType' must not be null");
 		return (inputMessage, context) -> readWithMessageReaders(inputMessage, context,
 				elementType,
-				reader -> {
+				(HttpMessageReader<T> reader) -> {
 					Optional<ServerHttpResponse> serverResponse = context.serverResponse();
 					if (serverResponse.isPresent() && inputMessage instanceof ServerHttpRequest) {
 						return reader.read(elementType, elementType, (ServerHttpRequest) inputMessage,