java.lang.NullPointerException: Cannot load from object array because "this.components" is null

[saber-wang]

When is' components' null?

io.netty.handler.codec.DecoderException: java.lang.NullPointerException: Cannot load from object array because "this.components" is null
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:280) ~[netty-codec-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286) [netty-handler-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) [netty-codec-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:714) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysPlain(NioEventLoop.java:615) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:578) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) [netty-transport-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) [netty-common-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) [netty-common-4.1.49.Final.jar:4.1.49.Final]
        at java.lang.Thread.run(Thread.java:832) [?:?]
Caused by: java.lang.NullPointerException: Cannot load from object array because "this.components" is null
        at io.netty.buffer.CompositeByteBuf.toComponentIndex0(CompositeByteBuf.java:911) ~[netty-buffer-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.buffer.CompositeByteBuf.addFlattenedComponents(CompositeByteBuf.java:482) ~[netty-buffer-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.handler.codec.ByteToMessageDecoder$2.cumulate(ByteToMessageDecoder.java:132) ~[netty-codec-4.1.49.Final.jar:4.1.49.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:274) ~[netty-codec-4.1.49.Final.jar:4.1.49.Final]

[saber-wang]

I found that 'components' may be null here by checking the source code, so is this a bug?

netty/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java

Line 485 in 48adb26

from = (CompositeByteBuf) buffer.unwrap();

netty/buffer/src/main/java/io/netty/buffer/WrappedCompositeByteBuf.java

Line 37 in 48adb26

super(wrapped.alloc());

netty/buffer/src/main/java/io/netty/buffer/CompositeByteBuf.java

Line 151 in 48adb26

components = null;

[normanmaurer]

4.1.49.Final is very old (many years old). Please upgrade to the latest netty release first and see if it reproduce still