[fix] Bound staking ledger correctly with MaxUnlockingChunks from configuration

[Ank4n]

Fixes #12227
Original PR #12289 and contributor: @MrishoLukamba

[Ank4n]

bot rebase

[paritytech-processbot]

Rebased

[kianenigma]

Looks good in itself. But there's a follow-up.

First, look into chill_other and what it does. You will find this wacky code in it:

if Nominators::<T>::contains_key(&stash) && Nominators::<T>::get(&stash).is_none() {
	Self::chill_stash(&stash);
	return Ok(())
}

This is basically checking: if a nominator is in a state where it is not decodable, then chill it.

I think we can take this a step further. Look into reap_stash. We can also add a clause to this function, that if a staker (regardless of the role), is in a state where it is not decodable (e.g. Ledger::contains_key(staler) && Ledger::get(staker).is_none()) then they can be reaped as well.

[Ank4n]

Looks good in itself. But there's a follow-up.

First, look into chill_other and what it does. You will find this wacky code in it:

if Nominators::<T>::contains_key(&stash) && Nominators::<T>::get(&stash).is_none() {
	Self::chill_stash(&stash);
	return Ok(())
}

This is basically checking: if a nominator is in a state where it is not decodable, then chill it.

I think we can take this a step further. Look into reap_stash. We can also add a clause to this function, that if a staker (regardless of the role), is in a state where it is not decodable (e.g. Ledger::contains_key(staler) && Ledger::get(staker).is_none()) then they can be reaped as well.

There is an issue here since ledger itself is undecodable, the stash can't be read to chill it.

let ledger = Self::ledger(&controller);

if Ledger::<T>::contains_key(&controller) && ledger.is_none() {
				Self::chill_stash(ledger.stash); // can't read ledger stash here
}

[kianenigma]

Looks good in itself. But there's a follow-up.
First, look into chill_other and what it does. You will find this wacky code in it:

if Nominators::<T>::contains_key(&stash) && Nominators::<T>::get(&stash).is_none() {
	Self::chill_stash(&stash);
	return Ok(())
}

This is basically checking: if a nominator is in a state where it is not decodable, then chill it.
I think we can take this a step further. Look into reap_stash. We can also add a clause to this function, that if a staker (regardless of the role), is in a state where it is not decodable (e.g. Ledger::contains_key(staler) && Ledger::get(staker).is_none()) then they can be reaped as well.

There is an issue here since ledger itself is undecodable, the stash can't be read to chill it.

let ledger = Self::ledger(&controller);

if Ledger::<T>::contains_key(&controller) && ledger.is_none() {
				Self::chill_stash(ledger.stash); // can't read ledger stash here
}

Assuming that we know the slash is only un-decodable because of the latter unlocking, we can still decode the first field of the struct, namely the stash.

Let's discuss this in a dedicated issue though.

[Ank4n]

bot rebase

[paritytech-processbot]

Rebased

[Ank4n]

bot merge