TxOutput.value.get() throws error
Closed this issue · 8 comments
This is probably a user error (Helios v0.6.5), but I am having trouble with .value.get(). My script is as follows:
minting voting_ballot
const POLLS_CLOSE: Time = Time::new(${pollsClose})
const REFERENCE_POLICY_HASH : MintingPolicyHash = MintingPolicyHash::new("${referencePolicyId}".serialize())
enum Redeemer {
Mint
}
func tx_output_spent(voting_asset: AssetClass, tx_out: TxOutput) -> Bool {
print(voting_asset.serialize().show());
print(tx_out.value.serialize().show());
print(tx_out.value.get(voting_asset).show()); // <-- THIS LINE THROWS AN ERROR
print("I don't show up in the error log");
tx_out.value.get(voting_asset) == 1
}
func assets_were_spent(minted_assets: Value, policy: MintingPolicyHash, outputs: []TxOutput) -> Bool {
tx_sends_to_self: Bool = minted_assets.get_policy(policy).all((asset_id: ByteArray, amount: Int) -> Bool {
print("FOO");
print(REFERENCE_POLICY_HASH.serialize().show());
print("BAR");
print(asset_id.show());
voting_asset: AssetClass = AssetClass::new(REFERENCE_POLICY_HASH, asset_id);
//print(voting_asset.serialize().show());
outputs.fold((spent: Bool, tx_out: TxOutput) -> Bool { tx_output_spent(voting_asset, tx_out) || spent }, false) && amount == 1
});
if (tx_sends_to_self) {
true
} else {
print("The minted assets were never sent to self");
false
}
}
func polls_are_still_open(time_range: TimeRange) -> Bool {
tx_during_polls_open: Bool = time_range.is_before(POLLS_CLOSE);
if (tx_during_polls_open) {
true
} else {
print("Invalid time range: " + time_range.serialize().show() + " (polls close at " + POLLS_CLOSE.serialize().show() + ")");
false
}
}
func main(redeemer: Redeemer, ctx: ScriptContext) -> Bool {
redeemer.switch {
Mint => {
tx: Tx = ctx.tx;
minted_policy: MintingPolicyHash = ctx.get_current_minting_policy_hash();
polls_are_still_open(tx.time_range) && assets_were_spent(tx.minted, minted_policy, tx.outputs)
}
}
}
The error/trace returned from compilation is:
{
"ScriptFailures": {
"mint:0": [
{
"validatorFailed": {
"error": "An error has occurred: User error:\
The machine terminated because of an error, either from a built-in function or from an explicit use of 'error'.",
"traces": [
"FOO",
"583a58383536666439336566386562653463373336343561636164616634373737313663653937333339303530323434363434636566333235373431",
"BAR",
"57696c6454616e677a2032",
"d8799f583a583835366664393365663865626534633733363435616361646166343737373136636539373333393035303234343634346365663332353734314b57696c6454616e677a2032ff",
"a240a1401a0011d28a581c25d7da6b446fee355edc48c07eefae55b4cdbcd534bea9c7dbd48f07a14b57696c6454616e677a203201"
]
}
}
]
}
}
Yeah, value.get(asset_class) throws an error if asset_class isn't found. Maybe it's too restrictive though and should just return 0, or I can add a method called get_safe
I remember there being a few cases where it made sense to implement it like this, but maybe in general the return value should be 0
Ah that makes sense. This could just be a doc fix too. Per the Chapter 4 documentation:
// Gets the amount of a specific AssetClass contained in a Value.
func get(self, asset_class: AssetClass) -> Int
No mention of error there so I was assuming it would just return 0. I will use .contains() instead.
Can you advise on .contains()? It is returning false, but it should be returning true:
const POLLS_CLOSE: Time = Time::new(${pollsClose})
const REFERENCE_POLICY_HASH: MintingPolicyHash = MintingPolicyHash::new("${referencePolicyId}".serialize())
const SINGLE_NFT: Int = 1
func tx_outputs_contain(voting_asset: AssetClass, outputs: []TxOutput) -> Bool {
outputs.fold((spent: Bool, tx_out: TxOutput) -> Bool {
print("Searching...");
print(voting_asset.serialize().show());
print(tx_out.value.serialize().show());
tx_out.value.contains(Value::new(voting_asset, SINGLE_NFT)) || spent
}, false)
}
func assets_were_spent(minted_assets: Value, policy: MintingPolicyHash, outputs: []TxOutput) -> Bool {
tx_sends_to_self: Bool = minted_assets.get_policy(policy).all((asset_id: ByteArray, amount: Int) -> Bool {
voting_asset: AssetClass = AssetClass::new(REFERENCE_POLICY_HASH, asset_id);
tx_outputs_contain(voting_asset, outputs) && amount == SINGLE_NFT
});
if (tx_sends_to_self) {
true
} else {
print("The NFTs with voting power for the ballots were never sent-to-self");
false
}
}
The traces are:
"traces": [
"Searching...",
"d8799f583a583835366664393365663865626534633733363435616361646166343737373136636539373333393035303234343634346365663332353734314b57696c6454616e677a2032ff",
"a240a1401a0011d28a581c0c33803c89eb26bf0094f7e09a211d4deb8bfb4e38b0af0191d0a4a5a14b57696c6454616e677a203201",
"Searching...",
"d8799f583a583835366664393365663865626534633733363435616361646166343737373136636539373333393035303234343634346365663332353734314b57696c6454616e677a2032ff",
"a240a1401a0011d28a581c56fd93ef8ebe4c73645acadaf477716ce97339050244644cef325741a14b57696c6454616e677a203201",
"Searching...",
"d8799f583a583835366664393365663865626534633733363435616361646166343737373136636539373333393035303234343634346365663332353734314b57696c6454616e677a2032ff",
"a440a1401a001c6920581c56fd93ef8ebe4c73645acadaf477716ce97339050244644cef325741a24c57696c6454616e677a203130014b57696c6454616e677a203301581c698d6cab8b61576b3b0becdf9f8ba041efe4006cfd29451280c7a95ea24c57696c6454616e677a203130014b57696c6454616e677a203501581cddbbf4ecd96a0237941bdf6e64c39db9d9d4d4088fa2e0eb9c7609e6a2581a436c756d73792056616c6c6579204c616e6420506c6f7420233201581a436c756d73792056616c6c6579204c616e6420506c6f7420233401",
"Searching..."
"d8799f583a583835366664393365663865626534633733363435616361646166343737373136636539373333393035303234343634346365663332353734314b57696c6454616e677a2032ff",
"a140a1401b0000000248bfc434",
]
I believe the third UTxO in the trace is the one that contains the send-to-self but I might be doing something wrong.
I think it has to do with my MintingPolicyHash::new I'm not finding much documentation on that though. The original Plutus Core says something about SHA256? I have this in JS code:
const REFERENCE_POLICY_ID = '56fd93ef8ebe4c73645acadaf477716ce97339050244644cef325741';
That SHA256 stuff is wrong (and a known documentation issue that IOG should've been fixed by now). MintingPolicyHash should be blake2b-224 hash of [0x02, ...scriptbytes] (for PlutusV2).
Indeed looks like an issue with MintingPolicyHash::new(). You should use const REFERENCE_POLICY_ID = #56fd93ef8ebe4c73645acadaf477716ce97339050244644cef325741 (bytearray, no semicolon). And then MintingPolicyHash::new(REFERENCE_POLICY_ID) (not serialize!)
MintingPolicyHash and PolicyID are the same thing (sorry for the confusion, but that's the fault of IOG for using different names for the same thing throughout their codebase, I just ended up picking the most verbose name).
Minor recommendation: you can use outputs.any instead of outputs.fold (is a bit more efficient because it quits the loop early).
Great. Works. Here's the final JS code with inline Helios. Closing.
const SINGLE_NFT = 1n;
const POLLS_OPEN = 1664462000000;
const POLLS_CLOSE = 1666242000000; // 10/20/22 00:00:00
const REFERENCE_POLICY_ID = '56fd93ef8ebe4c73645acadaf477716ce97339050244644cef325741';
const TEN_MINS = 600000;
function getBallotSourceCodeStr(referencePolicyId, pollsClose) {
return `
minting voting_ballot
const POLLS_CLOSE: Time = Time::new(${pollsClose})
const REFERENCE_POLICY_HASH: MintingPolicyHash = MintingPolicyHash::new(#${referencePolicyId})
const SINGLE_NFT: Int = 1
enum Redeemer {
Mint
}
func tx_outputs_contain(voting_asset: AssetClass, outputs: []TxOutput) -> Bool {
outputs.any((tx_out: TxOutput) -> Bool {
print("Searching...");
print(voting_asset.serialize().show());
print(tx_out.value.serialize().show());
tx_out.value.contains(Value::new(voting_asset, SINGLE_NFT))
})
}
func assets_were_spent(minted_assets: Value, policy: MintingPolicyHash, outputs: []TxOutput) -> Bool {
tx_sends_to_self: Bool = minted_assets.get_policy(policy).all((asset_id: ByteArray, amount: Int) -> Bool {
voting_asset: AssetClass = AssetClass::new(REFERENCE_POLICY_HASH, asset_id);
tx_outputs_contain(voting_asset, outputs) && amount == SINGLE_NFT
});
if (tx_sends_to_self) {
true
} else {
print("The NFTs with voting power for the ballots were never sent-to-self");
false
}
}
func polls_are_still_open(time_range: TimeRange) -> Bool {
tx_during_polls_open: Bool = time_range.is_before(POLLS_CLOSE);
if (tx_during_polls_open) {
true
} else {
print("Invalid time range: " + time_range.serialize().show() + " (polls close at " + POLLS_CLOSE.serialize().show() + ")");
false
}
}
func main(redeemer: Redeemer, ctx: ScriptContext) -> Bool {
redeemer.switch {
Mint => {
tx: Tx = ctx.tx;
minted_policy: MintingPolicyHash = ctx.get_current_minting_policy_hash();
polls_are_still_open(tx.time_range) && assets_were_spent(tx.minted, minted_policy, tx.outputs)
}
}
}
`;
}
I've also added a notice in the docs for the value.get() method that an error is thrown if asset_class isn't found (and a recommendation to use value.contains() if the goal is simply to check if value contains something).