Unable to query shielded balances of tokens received over IBC after updating epoch

[yito88]

It is related to not only IbcToken but also Erc20 tokens.

When the epoch is updated after receiving a token over IBC, this shielded balance has only the epoch when the token is received.

namada/apps/src/lib/client/rpc.rs

Lines 843 to 846 in c82a0b3

	let total_balance = balance
	.get(&(epoch, token.clone()))
	.cloned()
	.unwrap_or_default();

Currently, we update the conversion state only for pre-existing tokens.

namada/core/src/ledger/storage/masp_conversions.rs

Line 217 in c82a0b3

let tokens = address::tokens();

[cwgoes]

Would we need to add entries to the conversion table by default, for new tokens? This may be dangerous, since any number of new tokens can be created - we should think about this. First, though, can you explicate exactly what you mean?

[yito88]

I faced an issue with not being able to query the balance of IbcToken received at the previous epoch.
In query_shielded_balance(), compute_shielded_balance() returned the following MaspAmount as balance.

MaspAmount({(Epoch(2), Internal IbcToken: 8dc92a4843306e81055aad27883459d43410a3bb: atest1d93xxw368pjxxwfjvy6rsdpnxvcrvefcxycr2dtpv9jrydec8qengdfevs6rxdp3xpsnxcnzxv9rns): 10})

After that, to get the total_balance, it could get nothing with the current epoch (3).

namada/apps/src/lib/client/rpc.rs

Lines 843 to 846 in c82a0b3

	let total_balance = balance
	.get(&(epoch, token.clone()))
	.cloned()
	.unwrap_or_default();

[yito88]

We can query the shielded balance of IBC tokens now