Catch IllegalReferenceCountException

Closes gh-22594

spring-core/src/main/java/org/springframework/core/codec/AbstractSingleValueEncoder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -24,6 +24,7 @@ import reactor.core.publisher.Flux;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.io.buffer.PooledDataBuffer;
 import org.springframework.lang.Nullable;
 import org.springframework.util.MimeType;
@@ -51,7 +52,7 @@ public abstract class AbstractSingleValueEncoder<T> extends AbstractEncoder<T> {
 		return Flux.from(inputStream)
 				.take(1)
 				.concatMap(value -> encode(value, bufferFactory, elementType, mimeType, hints))
-				.doOnDiscard(PooledDataBuffer.class, PooledDataBuffer::release);
+				.doOnDiscard(PooledDataBuffer.class, DataBufferUtils::release);
 	}
 
 	/**

spring-core/src/main/java/org/springframework/core/io/buffer/DataBufferUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -39,6 +39,9 @@ import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Consumer;
 
+import io.netty.util.IllegalReferenceCountException;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.reactivestreams.Publisher;
 import org.reactivestreams.Subscription;
 import reactor.core.publisher.BaseSubscriber;
@@ -60,6 +63,8 @@ import org.springframework.util.Assert;
  */
 public abstract class DataBufferUtils {
 
+	private final static Log logger = LogFactory.getLog(DataBufferUtils.class);
+
 	private static final Consumer<DataBuffer> RELEASE_CONSUMER = DataBufferUtils::release;
 
 
@@ -494,7 +499,15 @@ public abstract class DataBufferUtils {
 		if (dataBuffer instanceof PooledDataBuffer) {
 			PooledDataBuffer pooledDataBuffer = (PooledDataBuffer) dataBuffer;
 			if (pooledDataBuffer.isAllocated()) {
-				return pooledDataBuffer.release();
+				try {
+					return pooledDataBuffer.release();
+				}
+				catch (IllegalReferenceCountException ex) {
+					if (logger.isDebugEnabled()) {
+						logger.debug("RefCount already at 0", ex);
+					}
+					return false;
+				}
 			}
 		}
 		return false;
@@ -523,7 +536,6 @@ public abstract class DataBufferUtils {
 	 * @return a buffer that is composed from the {@code dataBuffers} argument
 	 * @since 5.0.3
 	 */
-	@SuppressWarnings("unchecked")
 	public static Mono<DataBuffer> join(Publisher<? extends DataBuffer> dataBuffers) {
 		return join(dataBuffers, -1);
 	}

spring-web/src/main/java/org/springframework/http/codec/EncoderHttpMessageWriter.java

@@ -29,6 +29,7 @@ import org.springframework.core.codec.AbstractEncoder;
 import org.springframework.core.codec.Encoder;
 import org.springframework.core.codec.Hints;
 import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.io.buffer.PooledDataBuffer;
 import org.springframework.http.HttpLogging;
 import org.springframework.http.MediaType;
@@ -126,13 +127,13 @@ public class EncoderHttpMessageWriter<T> implements HttpMessageWriter<T> {
 					.flatMap(buffer -> {
 						message.getHeaders().setContentLength(buffer.readableByteCount());
 						return message.writeWith(Mono.just(buffer)
-								.doOnDiscard(PooledDataBuffer.class, PooledDataBuffer::release));
+								.doOnDiscard(PooledDataBuffer.class, DataBufferUtils::release));
 					});
 		}
 
 		if (isStreamingMediaType(contentType)) {
 			return message.writeAndFlushWith(body.map(buffer ->
-					Mono.just(buffer).doOnDiscard(PooledDataBuffer.class, PooledDataBuffer::release)));
+					Mono.just(buffer).doOnDiscard(PooledDataBuffer.class, DataBufferUtils::release)));
 		}
 
 		return message.writeWith(body);

spring-web/src/main/java/org/springframework/http/codec/multipart/MultipartHttpMessageWriter.java

@@ -40,6 +40,7 @@ import org.springframework.core.codec.Hints;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.core.io.buffer.PooledDataBuffer;
 import org.springframework.core.log.LogFormatUtils;
 import org.springframework.http.HttpEntity;
@@ -247,7 +248,7 @@ public class MultipartHttpMessageWriter extends LoggingCodecSupport
 		Flux<DataBuffer> body = Flux.fromIterable(map.entrySet())
 				.concatMap(entry -> encodePartValues(boundary, entry.getKey(), entry.getValue(), bufferFactory))
 				.concatWith(generateLastLine(boundary, bufferFactory))
-				.doOnDiscard(PooledDataBuffer.class, PooledDataBuffer::release);
+				.doOnDiscard(PooledDataBuffer.class, DataBufferUtils::release);
 
 		return outputMessage.writeWith(body);
 	}