Skip to content

Fix/zcash zip317 nu6.1 fees #1672

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Thorian1te merged 3 commits into from
Mar 31, 2026
Merged

Fix/zcash zip317 nu6.1 fees #1672

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
1aafbc4
fix(zcash): update ZIP-317 fee calculation for NU6.1 compatibility
Thorian1te Mar 31, 2026
fd1b287
fix(zcash): standardize memo fee calculation across all codepaths
Thorian1te Mar 31, 2026
6df2034
chore(zcash): add changeset for memo fee fix
Thorian1te Mar 31, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 6 additions & 0 deletions .changeset/fix-zcash-memo-fees.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
---
'@xchainjs/zcash-js': patch
'@xchainjs/xchain-zcash': patch
---

Fix memo fee double-counting in buildTx/prepareMaxTx and bypass in buildMaxTx by standardizing all codepaths to use getFee as the single source of truth for memo output slot calculation
12 changes: 6 additions & 6 deletions packages/xchain-zcash/__tests__/client.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -150,9 +150,9 @@ describe('Zcash client', () => {
const fees = await client.getFees({ memo: 'test' })
const expected = {
type: FeeType.FlatFee,
average: baseAmount(25000, ZEC_DECIMAL),
fast: baseAmount(25000, ZEC_DECIMAL),
fastest: baseAmount(25000, ZEC_DECIMAL),
average: baseAmount(30000, ZEC_DECIMAL),
fast: baseAmount(30000, ZEC_DECIMAL),
fastest: baseAmount(30000, ZEC_DECIMAL),
}
expect(deepSerialize(fees)).toEqual(deepSerialize(expected))
})
Expand All @@ -161,9 +161,9 @@ describe('Zcash client', () => {
const fees = await client.getFees({ sender: 't1eiZYPXWurGMxFwoTu62531s8fAiExFh88' })
const expected = {
type: FeeType.FlatFee,
average: baseAmount(30000, ZEC_DECIMAL),
fast: baseAmount(30000, ZEC_DECIMAL),
fastest: baseAmount(30000, ZEC_DECIMAL),
average: baseAmount(40000, ZEC_DECIMAL),
fast: baseAmount(40000, ZEC_DECIMAL),
fastest: baseAmount(40000, ZEC_DECIMAL),
}
expect(deepSerialize(fees)).toEqual(deepSerialize(expected))
})
Expand Down
4 changes: 2 additions & 2 deletions packages/xchain-zcash/src/client.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -251,8 +251,8 @@ abstract class Client extends UTXOClient {
// Calculate total value of all UTXOs
const totalValue = utxos.reduce((sum, utxo) => sum + utxo.value, 0)

// Calculate flat fee for this transaction (2 outputs: recipient + potential memo)
const fee = getFee(utxos.length, memo ? 2 : 1, memo)
// Calculate flat fee for this transaction (1 = recipient only; getFee adds memo slots)
const fee = getFee(utxos.length, 1, memo)

// Calculate max sendable amount
const maxAmount = totalValue - fee
Expand Down
13 changes: 5 additions & 8 deletions packages/zcash-js/src/builder.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,11 @@ const TX_VERSION_GROUP_ID = 0x26a7270a
const TX_VERSION = 0x80000005

const PKH_OUTPUT_SIZE = 34
const MARGINAL_FEE = 5000
const GRACE_ACTIONS = 2
const MARGINAL_FEE = 10000

function calculateFee(inCount: number, outCount: number): number {
const logicalActions = inCount + outCount
return MARGINAL_FEE * Math.max(GRACE_ACTIONS, logicalActions)
const logicalActions = Math.max(inCount, outCount)
return MARGINAL_FEE * Math.max(1, logicalActions)
}

/**
Expand Down Expand Up @@ -104,8 +103,7 @@ export async function buildMaxTx(
if (utxos.length === 0) throw new Error('No UTXOs provided')

// For max tx: NO change output, just recipient + optional memo
const outputCount = memo ? 2 : 1
const fee = calculateFee(utxos.length, outputCount)
const fee = getFee(utxos.length, 1, memo) // 1 = recipient only; getFee adds memo slots

// Calculate total value and max sendable amount
const totalValue = sumBy(utxos, (u: UTXO) => u.satoshis)
Expand Down Expand Up @@ -152,8 +150,7 @@ export async function buildTx(
if (memo && memo.length > 80) throw new Error('Memo too long')

const inputs = selectUTXOS(utxos, amount, memo)
const outputCount = memo ? 3 : 2 // change + to + memo (if exists)
const fee = getFee(inputs.length, outputCount, memo)
const fee = getFee(inputs.length, 2, memo) // 2 = change + recipient; getFee adds memo slots
const change = sumBy(inputs, (u: UTXO) => u.satoshis) - amount - fee
if (change < 0) throw new Error('Not enough funds')

Expand Down
Loading