fix: fence inter-mint transfer operations

src/lnurlcash/ops.transfer.cases.ts

@@ -0,0 +1,136 @@
+import {describe, expect, it} from 'vitest'
+import {createMockMint} from 'lnurlcash-conformance/mock-mint'
+import {noteK1} from 'lnurlcash-kit'
+
+import {transferBetweenMints} from './ops'
+import {requiredValue} from './test-utils'
+import {expectBurned, makeBearer, mint, secret, settleWhenRequested} from './ops.testHarness'
+
+describe('transferBetweenMints', () => {
+  const fastPoll = {intervalMs: 10, intervalCapMs: 50, maxWaitMs: 5_000}
+
+  it('moves value to another mint: melt at source, claim + rotate at target', async () => {
+    const source = await mint()
+    const target = await mint({testHooks: true})
+    const k1 = secret('40')
+    const bearer = await makeBearer(source, k1, 21_000)
+    const pending = transferBetweenMints([bearer], 21_000, `mint@127.0.0.1:${target.port}`, {
+      poll: fastPoll,
+    })
+    const preimage = await settleWhenRequested(target)
+    const result = await pending
+    expect(result.outcome).toBe('settled')
+    expect(result.invoice).toMatch(/^lnbc/)
+    expect(result.quote).toEqual({
+      requestedMsat: 21_000,
+      grossMsat: 21_000,
+      targetMintFeeMsat: 0,
+      sourceMeltFeeReserveMsat: 0,
+    })
+    expect(result.sourceServer).not.toBe(result.targetServer)
+    await expectBurned(source, k1)
+    const claimed = requiredValue(result.mintedAtTarget)
+    expect(claimed.rotated).toBe(true)
+    expect(claimed.note.amount).toBe(21_000)
+    expect(claimed.note.verified).toBe(true)
+    expect(target.state.noteState(preimage)).toBe('burned')
+    const newK1 = requiredValue(noteK1(claimed.note.url))
+    expect(newK1).not.toBe(preimage)
+    expect(target.state.noteState(newK1)).toBe('outstanding')
+  })
+
+  it('refuses an amount no source mint can cover', async () => {
+    const source = await mint()
+    const target = await mint()
+    const k1 = secret('41')
+    const bearer = await makeBearer(source, k1, 5_000)
+    await expect(
+      transferBetweenMints([bearer], 50_000, `mint@127.0.0.1:${target.port}`),
+    ).rejects.toThrow(/enough/)
+    expect(source.state.noteState(k1)).toBe('outstanding')
+  })
+
+  it('rejects a transfer onto the mint the notes are already on', async () => {
+    const instance = await mint()
+    const k1 = secret('42')
+    const bearer = await makeBearer(instance, k1, 21_000)
+    await expect(
+      transferBetweenMints([bearer], 21_000, `mint@127.0.0.1:${instance.port}`),
+    ).rejects.toThrow(/different target/)
+    expect(instance.state.noteState(k1)).toBe('outstanding')
+  })
+
+  it('moves nothing when the target mint is unreachable', async () => {
+    const source = await mint()
+    const dead = await createMockMint()
+    const deadAddress = `mint@127.0.0.1:${dead.port}`
+    await dead.close()
+    const k1 = secret('43')
+    const bearer = await makeBearer(source, k1, 50_000)
+    await expect(transferBetweenMints([bearer], 21_000, deadAddress)).rejects.toThrow()
+    expect(source.state.noteState(k1)).toBe('outstanding')
+  })
+
+  it('recovers from a melt whose answer was lost once the target invoice settles', async () => {
+    const source = await mint({unconfirmedMutation: true})
+    const target = await mint({testHooks: true})
+    const k1 = secret('44')
+    const bearer = await makeBearer(source, k1, 21_000)
+    const pending = transferBetweenMints([bearer], 21_000, `mint@127.0.0.1:${target.port}`, {
+      poll: fastPoll,
+    })
+    await settleWhenRequested(target)
+    const result = await pending
+    expect(result.outcome).toBe('settled')
+    await expectBurned(source, k1)
+    expect(result.mintedAtTarget?.note.amount).toBe(21_000)
+    expect(result.mintedAtTarget?.rotated).toBe(true)
+  })
+
+  it('surfaces the claimable preimage note when the claim fails after a settled melt', async () => {
+    const source = await mint()
+    const target = await mint({testHooks: true, echoWrongK1: true})
+    const k1 = secret('45')
+    const bearer = await makeBearer(source, k1, 21_000)
+    const pending = transferBetweenMints([bearer], 21_000, `mint@127.0.0.1:${target.port}`, {
+      poll: fastPoll,
+    })
+    const preimage = await settleWhenRequested(target)
+    const result = await pending
+    expect(result.outcome).toBe('settled-claim-failed')
+    await expectBurned(source, k1)
+    const note = requiredValue(result.claimMaterial?.note)
+    expect(noteK1(note.url)).toBe(preimage)
+    expect(note.verified).toBe(false)
+    expect(note.amount).toBe(21_000)
+    expect(result.claimMaterial?.withdrawLink).toContain(`${target.port}`)
+  })
+
+  it('grosses the carve up for the target mint fee, refusing when only the net is covered', async () => {
+    const source = await mint()
+    const target = await mint({baseFeeMsat: 1_000, feePpm: 2_000})
+    const k1 = secret('46')
+    const bearer = await makeBearer(source, k1, 100_000)
+    await expect(
+      transferBetweenMints([bearer], 100_000, `mint@127.0.0.1:${target.port}`),
+    ).rejects.toThrow(/enough/)
+    expect(source.state.noteState(k1)).toBe('outstanding')
+  })
+
+  it('restores the source note, re-secured, when the melt fails', async () => {
+    const source = await mint({meltAlwaysFails: true})
+    const target = await mint({testHooks: true})
+    const k1 = secret('47')
+    const bearer = await makeBearer(source, k1, 21_000)
+    const result = await transferBetweenMints([bearer], 21_000, `mint@127.0.0.1:${target.port}`, {
+      poll: {intervalMs: 10, intervalCapMs: 20, maxWaitMs: 300},
+    })
+    expect(result.outcome).toBe('failed-funds-returned')
+    expect(result.mintedAtTarget).toBeUndefined()
+    expect(source.state.noteState(k1)).toBe('burned')
+    const returnedK1 = requiredValue(noteK1(result.carve.note.url))
+    expect(returnedK1).not.toBe(k1)
+    expect(source.state.noteState(returnedK1)).toBe('outstanding')
+    expect(result.carve.note.amount).toBe(21_000)
+  })
+})

src/lnurlcash/ops/transfer.ts

@@ -24,7 +24,7 @@ import {
   rotateNote,
   sameInvoice,
   serverOf,
-  withNewK1
+  withNewK1,
 } from 'lnurlcash-kit'
 import type {LnurlcashOptions} from 'lnurlcash-kit'
 import type {Bearer, NewBearer} from '../types'
@@ -33,7 +33,8 @@ import {ensureExactAmount} from './carve'
 import type {ClaimedNote} from './mint'
 import {claimFromPreimage, prepareMint} from './mint'
 import type {PollOptions} from './shared'
-import {pollVerifyUntilSettled} from './shared'
+import type {FundOperationOptions} from './shared'
+import {assertFundOwner, pollVerifyUntilSettled} from './shared'
 
 export type TransferOutcome =
   // the melt settled and the target note was claimed (and rotated)
@@ -102,15 +103,16 @@ export type TransferOptions = {
   poll?: PollOptions
   // kit transport overrides (fetch injection, timeouts)
   kit?: LnurlcashOptions
+  assertOwner?: () => void
 }
 
 export const transferBetweenMints = async (
   bearers: Bearer[],
   amountMsat: number,
   targetMint: string,
-  {poll = {}, kit = {}}: TransferOptions = {}
+  {poll = {}, kit = {}, assertOwner}: TransferOptions = {},
 ): Promise<TransferResult> => {
-  const options = kit
+  const options: FundOperationOptions = assertOwner ? {...kit, assertOwner} : kit
   if (!Number.isInteger(amountMsat) || amountMsat <= 0) {
     throw new Error('Amount must be a positive whole number of msat.')
   }
@@ -120,7 +122,7 @@ export const transferBetweenMints = async (
   const prepared = await prepareMint(targetMint, amountMsat, options)
   if (!prepared.verifyUrl) {
     throw new Error(
-      'The target mint did not advertise a verify URL - a transfer there cannot auto-claim.'
+      'The target mint did not advertise a verify URL - a transfer there cannot auto-claim.',
     )
   }
   const verifyUrl = prepared.verifyUrl
@@ -129,19 +131,17 @@ export const transferBetweenMints = async (
   // goes nowhere (melt pays an invoice; the same mint's invoice just
   // re-mints into itself, paying fees for nothing)
   const eligible = bearers.filter(
-    b => !b.spent && b.callback !== '' && !b.deviceId && noteK1(b.url)
+    (b) => !b.spent && b.callback !== '' && !b.deviceId && noteK1(b.url),
   )
-  const offTarget = eligible.filter(b => serverOf(b.url) !== targetServer)
+  const offTarget = eligible.filter((b) => serverOf(b.url) !== targetServer)
   if (eligible.length > 0 && offTarget.length === 0) {
-    throw new Error(
+    throw new Error("That's the mint these notes are already on - pick a different target.")
-      'That\'s the mint these notes are already on - pick a different target.'
-    )
   }
   const quote: TransferQuote = {
     requestedMsat: amountMsat,
     grossMsat: prepared.grossMsat,
     targetMintFeeMsat: prepared.grossMsat - amountMsat,
-    sourceMeltFeeReserveMsat: 0
+    sourceMeltFeeReserveMsat: 0,
   }
   // carving burns its inputs server-side, so it happens only once the
   // target is known good and the invoice exists
@@ -151,12 +151,13 @@ export const transferBetweenMints = async (
   const claimMaterial: TransferClaimMaterial = {
     invoice,
     withdrawLink: prepared.withdrawLink,
-    expectedNoteValueMsat: prepared.expectedNoteValueMsat
+    expectedNoteValueMsat: prepared.expectedNoteValueMsat,
   }
   // from here on the carve's fresh secrets exist only in this result - the
   // flow never throws again; every outcome carries them
   const base = {carve, quote, invoice, verifyUrl, sourceServer, targetServer}
   const k1 = requireNoteK1(carve.note.url)
+  if (carve.consumed.length === 0) assertFundOwner(options)
   try {
     await meltNote(carve.note.callback, k1, invoice, options)
   } catch (err) {
@@ -197,20 +198,16 @@ export const transferBetweenMints = async (
       // the melt settled - the money is now the preimage note at the
       // target and nowhere else; surface it rather than lose it
       const note: NewBearer = {
-        url: buildNoteUrl(
+        url: buildNoteUrl(prepared.withdrawLink, proof.preimage, prepared.expectedNoteValueMsat),
-          prepared.withdrawLink,
-          proof.preimage,
-          prepared.expectedNoteValueMsat
-        ),
         callback: '',
         amount: prepared.expectedNoteValueMsat,
-        verified: false
+        verified: false,
       }
       if (prepared.mintPubkey) note.mintPubkey = prepared.mintPubkey
       return {
         ...base,
         outcome: 'settled-claim-failed',
-        claimMaterial: {...claimMaterial, note}
+        claimMaterial: {...claimMaterial, note},
       }
     }
   } catch {
@@ -229,14 +226,9 @@ export const transferBetweenMints = async (
           ...carve,
           note: {
             ...carve.note,
-            url: withNewK1(
+            url: withNewK1(carve.note.url, rotated.k1, carve.note.amount, rotated.signature),
-              carve.note.url,
+          },
-              rotated.k1,
+        },
-              carve.note.amount,
-              rotated.signature
-            )
-          }
-        }
       }
     } catch (err) {
       if (err instanceof PendingNoteError || err instanceof NoteSpentError) {
@@ -251,7 +243,7 @@ export const transferBetweenMints = async (
           url: withNewK1(carve.note.url, err.newSecrets[0], carve.note.amount),
           callback: carve.note.callback,
           amount: carve.note.amount,
-          verified: false
+          verified: false,
         }
         if (carve.note.mintPubkey) rescuedNote.mintPubkey = carve.note.mintPubkey
         return {...base, outcome: 'failed-funds-returned', rescuedNote}