Unloading a wallet with in timeframe that is unlocked for crashes RPC server without any log/trace

[furqansiddiqui]

Describe the issue

For example, you unlock a wallet with "walletpassphrase" command for next 10 seconds, but for some reason unload wallet command is called before the wallet is locked again, it causes RPC server to crash and I didn't find any relevant help from debug.log file

This is important because whole idea of dynamically loading/unloading wallet is to help build applications that can work with multiple wallets more effectively, while its easy for an application to load all and every wallet but in our case we want to unload wallet right after necessary commands have passed (i.e. in PHP OOP I have registered a shutdown function for all wallets instances to automatically unload)

What behavior did you expect?

unload command to return an error message in such circumstances

How reliably can you reproduce the issue, what are the steps to do so?

1. Call "walletpassphrase" to unlock wallet for next N seconds
2. Issue "unloadwallet" command before those N seconds have passed

[promag]

@furqansiddiqui thanks for the report, fix on it's way.