[etherscan] Fix invalid transfer merge for fee transactions (#949)

Author: Cr0WD

src/plugins/etherscan/__tests__/converters/merge-transfer.test.ts

@@ -0,0 +1,63 @@
+import { Transaction } from '../../../../types/zenmoney'
+import { mergeTransferTransactions } from '../../common/converters'
+
+function makeTransaction (
+  movementId: string,
+  accountId: string,
+  sum: number
+): Transaction {
+  return {
+    hold: null,
+    date: new Date('2026-01-01T00:00:00.000Z'),
+    movements: [
+      {
+        id: movementId,
+        account: { id: accountId },
+        invoice: null,
+        sum,
+        fee: 0
+      }
+    ],
+    merchant: {
+      fullTitle: 'merchant',
+      mcc: null,
+      location: null
+    },
+    comment: null
+  }
+}
+
+describe('mergeTransferTransactions', () => {
+  it('merges only opposite sign movements with same id', () => {
+    const result = mergeTransferTransactions([
+      makeTransaction('hash-1', 'account-1', -100),
+      makeTransaction('hash-1', 'account-2', 100)
+    ])
+
+    expect(result).toHaveLength(1)
+    expect(result[0].movements).toHaveLength(2)
+    expect(result[0].merchant).toBe(null)
+  })
+
+  it('does not merge fee-like movements with same sign', () => {
+    const result = mergeTransferTransactions([
+      makeTransaction('hash-1_fee', 'account-1', -10),
+      makeTransaction('hash-1_fee', 'account-2', -10)
+    ])
+
+    expect(result).toHaveLength(2)
+    expect(result[0].movements).toHaveLength(1)
+    expect(result[1].movements).toHaveLength(1)
+  })
+
+  it('does not merge when one side has zero amount', () => {
+    const result = mergeTransferTransactions([
+      makeTransaction('hash-1_fee', 'account-1', -10),
+      makeTransaction('hash-1_fee', 'account-2', 0)
+    ])
+
+    expect(result).toHaveLength(2)
+    expect(result[0].movements).toHaveLength(1)
+    expect(result[1].movements).toHaveLength(1)
+  })
+})

src/plugins/etherscan/common/converters.ts

@@ -1,25 +1,86 @@
 import { Transaction } from '../../../types/zenmoney'
 
+function canBeMergedAsTransfer (left: Transaction, right: Transaction): boolean {
+  const leftMovement = left.movements[0]
+  const rightMovement = right.movements[0]
+
+  if (leftMovement == null || rightMovement == null) {
+    return false
+  }
+
+  if (leftMovement.sum == null || rightMovement.sum == null) {
+    return false
+  }
+
+  if (leftMovement.sum === 0 || rightMovement.sum === 0) {
+    return false
+  }
+
+  if (leftMovement.sum < 0) {
+    return rightMovement.sum > 0
+  }
+
+  return rightMovement.sum < 0
+}
+
 export function mergeTransferTransactions (transactions: Transaction[]): Transaction[] {
-  const list = transactions.reduce<{ [key in string]?: Transaction }>((acc, item) => {
-    const movementId = item.movements[0].id ?? ''
-    const existingItem = acc[movementId]
-
-    if (existingItem == null) {
-      acc[movementId] = item
-    } else {
-      acc[movementId] = {
-        ...existingItem,
-        movements: [
-          existingItem.movements[0],
-          item.movements[0]
-        ],
-        merchant: null
+  const result: Transaction[] = []
+  const usedIndexes = new Set<number>()
+
+  for (let i = 0; i < transactions.length; i++) {
+    if (usedIndexes.has(i)) {
+      continue
+    }
+
+    const item = transactions[i]
+    const movement = item.movements[0]
+    const movementId = movement?.id ?? ''
+
+    if (movement == null || movementId === '') {
+      result.push(item)
+      continue
+    }
+
+    let pairIndex = -1
+    for (let j = i + 1; j < transactions.length; j++) {
+      if (usedIndexes.has(j)) {
+        continue
+      }
+
+      const candidate = transactions[j]
+      const candidateMovement = candidate.movements[0]
+      const candidateMovementId = candidateMovement?.id ?? ''
+
+      if (candidateMovement == null || candidateMovementId !== movementId) {
+        continue
+      }
+
+      if (canBeMergedAsTransfer(item, candidate)) {
+        pairIndex = j
+        break
       }
     }
 
-    return acc
-  }, {})
+    if (pairIndex === -1) {
+      result.push(item)
+      continue
+    }
+
+    const pair = transactions[pairIndex]
+    const pairMovement = pair.movements[0]
+
+    if (pairMovement == null) {
+      result.push(item)
+      continue
+    }
+
+    usedIndexes.add(pairIndex)
+    result.push({
+      ...item,
+      movements: [movement, pairMovement],
+      merchant: null
+    })
+  }
 
-  return Object.values(list) as Transaction[]
+  return result
 }

src/plugins/etherscan/tokens/converters.ts

@@ -131,7 +131,5 @@ export function convertTransactions (
       Boolean(transaction?.movements.some((movement) => movement.sum !== 0))
     )
 
-  console.log('LST', list)
-
   return list
 }