fix: bank store migration

[okwme]

Description

Closes: #13797

While running an upgrade handler for gaia v8 we supplement the bank metadata. In doing so we found that the metadata was not retrievable using the new KV store pattern in v0.46. Coincidentally, we were trying to retrieve the metadata before the migration had been run. Ironically, after fixing the order, it was still not retrievable because there was a bug in how the store migration was written.

The current implementation infers that the store prefix needs to be included in the key, however the prefix is already omitted as part of the prefix store used in the migration code (and subsequent test).

We iterated over the whole store to check what was the key. When we incorrectly tried to retrieve before the migration we printed out a key of uatomuatom. Once we switched the migrations to run before we tried retrieving the metadata we printed out the key of uatomu. This demonstrates the migration is applied to a key of the wrong length. The addition of one letter is from the incorrect expectation that the store prefix (0x1) should be accounted for.

for ; oldDenomMetaDataIter.Valid(); oldDenomMetaDataIter.Next() {
		oldKey := oldDenomMetaDataIter.Key()
		l := len(oldKey)/2 + 1

instead of

for ; oldDenomMetaDataIter.Valid(); oldDenomMetaDataIter.Next() {
		oldKey := oldDenomMetaDataIter.Key()
		l := len(oldKey) / 2

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[julienrbrt]

I think your PR should target main. Then we can use mergifyio to backport to v0.46

[alexanderbez]

I think your PR should target main. Then we can use mergifyio to backport to v0.46

Si!

Also, how did other chains like Umee not run into this? This means the current migration is invalid. If so, that would infer that all current versions of 0.46.x are broken.

[okwme]

closing in favor of #13821 which targets main.

@alexanderbez I don't believe anyone is using the on chain metadata information for anything important at this point. My understanding is that if you want to know the metadata of a token, generally you'd go to https://github.com/cosmos/chain-registry which also contains coin metadata.