readSpecificJsonMessage can panic on queue overflow

[quadtrix]

In some cases readSpecificJsonMessage panics with the following error:

Delta Agent 0.1.-beta1
panic: runtime error: index out of range [1] with length 1

goroutine 23 [running]:
github.com/quadtrix/basicqueue.(*BasicQueue).readSpecificJsonMessage(0xc0001185a0, 0x1)
/home/nhtbrink/go/pkg/mod/github.com/quadtrix/basicqueue@v0.0.0-20230808074438-d245b21dd56b/basicqueue.go:548 +0x79f
github.com/quadtrix/basicqueue.(*BasicQueue).ReadJsonWithHistory(0xc0001185a0, {0xc0000b2000, 0x35}, {0xc00013afa0, 0x63, 0xaa?})
/home/nhtbrink/go/pkg/mod/github.com/quadtrix/basicqueue@v0.0.0-20230808074438-d245b21dd56b/basicqueue.go:633 +0x4bc
github.com/quadtrix/client_connector.(*ClientConnection).heartbeatSender(0xc0000ae000, 0x0?, 0x0?)
/home/nhtbrink/go/pkg/mod/github.com/quadtrix/client_connector@v0.0.0-20221009195911-96e8762ce08f/client_connector.go:531 +0x468
created by github.com/quadtrix/client_connector.New
/home/nhtbrink/go/pkg/mod/github.com/quadtrix/client_connector@v0.0.0-20221009195911-96e8762ce08f/client_connector.go:164 +0xafc

This is probably the scenario:

• readSpecificJsonMessage is called and wants to read message nr 1 from a queue with 2 messages
• checkForExpiry is running at the same time and removes message nr 0 from the same queue, making message nr 1 now message nr 0.
• When the message needs to be retrieved for readSpecificJsonMessage, message nr 1 no longer exists and causes a panic since the read tries to read beyond the end of the queue

Probable solution:
Use queue locking for read actions as well as write actions.