The Input class changes its buffer when deserialize a string

[NPE0]

Describe the bug
kryo 4...
When I use a single byte[] array to deserialize from multiple streams, sometimes there is a crash with the error

com.esotericsoftware.kryo.kryo5.io.KryoBufferUnderflowException: Buffer underflow

This is a real scenario when using a cache that contains data shared between threads.
As I see, it is a known problem in readAscii method. Because it was fixed in 5.. version of the library.
But I think it will be good to fix it in 4... version family too.

At the moment, I fixed this by simply copying the input array to a new one.
In terms of cost, this is similar to using an intermediate char[] buffer in "readAscii"

To Reproduce
I wrote a test that reproduces the situation. See "*Additional context".

Environment:

• JDK Version: [1.8]
• Kryo Version: [4.0.2]

Additional context
KryoBugLab.zip

[theigl]

Is the fix backwards compatible? If it is, you could provide a PR that backports it to Kryo 4.

I don't actively maintain Kryo 4 anymore, but if users provide fixes, I can do a release.

[mrniko]

Getting same issue with the latest Kryo version

Caused by: com.esotericsoftware.kryo.io.KryoBufferUnderflowException: Buffer underflow.
	at com.esotericsoftware.kryo.io.Input.require(Input.java:221)
	at com.esotericsoftware.kryo.io.Input.readVarInt(Input.java:447)
	at com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:145)
	at com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:758)
	at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:869)
	at org.redisson.codec.Kryo5Codec$4.decode(Kryo5Codec.java:153)
	at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:454)
	at org.redisson.client.handler.CommandDecoder.decodeCommandBatch(CommandDecoder.java:308)
	at org.redisson.client.handler.CommandDecoder.decodeCommand(CommandDecoder.java:234)
	at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:150)
	at org.redisson.client.handler.CommandDecoder.decode(CommandDecoder.java:126)
	at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection