Koios provider: lovelace fields will change from strings to numbers in Koios v1.5

Koios plans to change how it sends lovelace amounts. Today they come as strings ("2000000"). From Koios v1.5.0 they will come as JSON numbers (2000000). This is a breaking change on their side, with no date yet:

• the caution note in the v1.4.2 release
• cardano-community/koios-artifacts#412
• cardano-community/koios-artifacts#296

Why it matters for evolution-sdk

The Koios provider schemas expect strings for these fields. Some examples in sdk/provider/internal/Koios.ts:

• protocol parameters: key_deposit, pool_deposit, coins_per_utxo_size, drep_deposit, gov_action_deposit, min_utxo_value, min_pool_cost
• UTxOs: value and asset quantity
• address balance, account rewards_available, and tx fee / deposit

I took today's mainnet /epoch_params response and turned those seven fields into numbers. Decoding it with ProtocolParametersSchema then fails:

gov_action_deposit: NumberFromString — Encoded side transformation failure

So once Koios v1.5 is live, getProtocolParameters() will fail. So will building a transaction that relies on it. I expect the other calls above to fail the same way.

Accepting numbers is not enough on its own. Some lovelace values are bigger than 2^53, like the stake totals. JSON.parse rounds those without any error.

Possible directions

• Ask Koios for text directly: adding ::text in select works today and should keep working after v1.5. For example, ?select=epoch_no,key_deposit::text. Koios suggests this in their release note. I checked on mainnet: with their preview flag _lovelace_numeric=true, active_stake comes back as a number, and active_stake::text turns it back into a string.
• Or read the JSON in a way that keeps big numbers exact.
• Tests with numbers in these fields would catch the change before Koios ships it.

Beginne in sdk/provider/internal/Koios.ts und verfolge ProtocolParametersSchema durch getProtocolParameters(); untersuche anschließend die Schemas für UTxOs, Bilanzen, Rewards, Gebühren und Deposits. Reproduziere den Fehler mit numerischen lovelace-Feldern, vergleiche die im Issue beschriebenen Ansätze zum Erhalt der Payload und füge Tests hinzu, die Zahlen in allen betroffenen Feldern verwenden. Als abgeschlossen gilt die Aufgabe, wenn diese Responses ohne Präzisionsverlust dekodiert werden.