always-yes-drep

A gimmick plutus based DRep that can only vote yes.

The hash of this DRep on the sancho testnet is given by 1a0b5b7088651572aea3dda465920f7382f6b251f231231dc3762803.

Compile the script and register Drep

The script can be compiled with nix run .#write-scripts, which will output it in text envelope format at /assets/V3/alwaysVoteYesDrep.plutus. Note that this is parametrized by an utxo ref that needs to be consumed to register this Drep (see plutus-scripts/exe/Main.hs).

With this script compiled we can then determine the drep script hash via

cardano-cli hash script --script-file ./assets/V3/alwaysVoteYesDrep.plutus > alwaysVoteYesDrep.hash

With the following we can create a registration certificate.

cardano-cli conway governance drep registration-certificate \
 --drep-script-hash $(cat alwaysVoteYesDrep.hash) \
 --key-reg-deposit-amt 500000000 \
 --out-file register-alwaysVoteYesDrep.cert

Note that sending this cert to the chain requires us to witness the drep via,

cardano-cli conway transaction build --testnet-magic 4 \
 --tx-in $(cardano-cli query utxo --address $(cat payment.addr) --output-json --testnet-magic 4 | jq -r 'keys[0]') \
 --tx-in-collateral $(cardano-cli query utxo --address $(cat payment.addr) --output-json --testnet-magic 4 | jq -r 'keys[0]') \
 --certificate-file register-alwaysVoteYesDrep.cert \
 --certificate-script-file assets/V3/alwaysVoteYesDrep.plutus \
 --certificate-redeemer-value {} \
 --change-address $(cat payment.addr) 
 --out-file tx
cardano-cli transaction sign --testnet-magic 4 --signing-key-file payment.skey --tx-body-file tx --out-file tx.signed
cardano-cli transaction submit --testnet-magic 4 --tx-file tx.signed

We can check that it is registered via

cardano-cli conway query drep-state --testnet-magic 4 --all-dreps | jq 'map(select(.[0].scriptHash == "1a0b5b7088651572aea3dda465920f7382f6b251f231231dc3762803"))'

The always yes voting drep can not deregister, but it can renew its drep timer or register again.

How to use delegate to it

To delegate to this Drep use

cardano-cli conway stake-address vote-delegation-certificate \
--stake-verification-key-file stake.vkey \
--drep-script-hash $(cat alwaysVoteYesDrep.hash) \
--out-file vote-deleg.cert

and submit it to the chain.

How to vote yes with it

To vote you can use

cardano-cli conway governance vote create \
    --yes \
    --governance-action-tx-id "yourGovActionHashHere" \
    --governance-action-index "yourGovActionIndexHere" \
    --drep-script-hash $(cat alwaysVoteYesDrep.hash) \
    --out-file myGovAction.vote

and submit it to the chain by witnessing the drep script via the following build-raw command (there is a bug in the cli)

ADA_ONLY_UTXO=$(cardano-cli query utxo --address $(cat payment.addr) --output-json --testnet-magic 4 | jq -r 'to_entries | map(select(.value.value | keys | length == 1 and contains(["lovelace"]))) | .[0].key')
ADA_ONLY_UTXO_LOVELACE_VALUE=$(cardano-cli query utxo --address $(cat payment.addr) --output-json --testnet-magic 4 | jq '.'\"$ADA_ONLY_UTXO\"'' | jq '.value.lovelace')
FEE=5000000
PAYMENT_RETURN_LOVELACE=$(($ADA_ONLY_UTXO_LOVELACE_VALUE - $FEE))
cardano-cli query protocol-parameters --testnet-magic 4 --out-file pparams.json
cardano-cli conway transaction build-raw \
 --tx-in $ADA_ONLY_UTXO \
 --tx-in-collateral $ADA_ONLY_UTXO \
 --vote-file myGovAction.vote \
 --vote-script-file alwaysVoteYesDrep.plutus \
 --vote-redeemer-value {} \
 --vote-execution-units "(4000000000,4000000)" \
 --tx-out $(cat payment.addr)+$PAYMENT_RETURN_LOVELACE \
 --fee $FEE \
 --protocol-params-file pparams.json \
 --out-file tx
 cardano-cli transaction sign --testnet-magic 4 --signing-key-file payment.skey --tx-body-file tx --out-file tx.signed
 cardano-cli transaction submit --testnet-magic 4 --tx-file tx.signed

And to convince you that the script can never vote no, try voting not with it :)