fix: add workaround for rippled UNLModify encoding bug (#1830)

* initial patch

* clean up

* make ts happy

* fix typing

* respond to comments

* Revert "respond to comments"

This reverts commit 689768bbf1.

* Publish

 - ripple-address-codec@4.2.1-beta.0
 - ripple-binary-codec@1.2.1-beta.0
 - ripple-keypairs@1.1.1-beta.0
 - xrpl@2.0.3-beta.0

* add helper comments

Co-authored-by: Nathan Nichols <natenichols@cox.net>

packages/ripple-binary-codec/src/binary.ts

@@ -66,6 +66,7 @@ function serializeObject(object: JsonObject, opts: OptionObject = {}): Buffer {
   const filter = signingFieldsOnly
     ? (f: FieldInstance): boolean => f.isSigningField
     : undefined
+
   coreTypes.STObject.from(object, filter).toBytesSink(bytesList)
 
   if (suffix) {

packages/ripple-binary-codec/src/enums/index.ts

@@ -1,6 +1,7 @@
 import * as enums from './definitions.json'
 import { SerializedType } from '../types/serialized-type'
 import { Buffer } from 'buffer/'
+import { BytesList } from '../binary'
 
 const TYPE_WIDTH = 2
 const LEDGER_ENTRY_WIDTH = 2
@@ -29,8 +30,8 @@ function fieldHeader(type: number, nth: number): Buffer {
 /*
  * @brief: Bytes, name, and ordinal representing one type, ledger_type, transaction type, or result
  */
-class Bytes {
-  readonly bytes: Uint8Array
+export class Bytes {
+  readonly bytes: Buffer
 
   constructor(
     readonly name: string,
@@ -47,7 +48,7 @@ class Bytes {
     return this.name
   }
 
-  toBytesSink(sink): void {
+  toBytesSink(sink: BytesList): void {
     sink.put(this.bytes)
   }
 

packages/ripple-binary-codec/src/serdes/binary-serializer.ts

@@ -126,7 +126,11 @@ class BinarySerializer {
    * @param field field to write to BinarySerializer
    * @param value value to write to BinarySerializer
    */
-  writeFieldAndValue(field: FieldInstance, value: SerializedType): void {
+  writeFieldAndValue(
+    field: FieldInstance,
+    value: SerializedType,
+    isUnlModifyWorkaround = false,
+  ): void {
     const associatedValue = field.associatedType.from(value)
     assert.ok(associatedValue.toBytesSink !== undefined)
     assert.ok(field.name !== undefined)
@@ -134,7 +138,7 @@ class BinarySerializer {
     this.sink.put(field.header)
 
     if (field.isVariableLengthEncoded) {
-      this.writeLengthEncoded(associatedValue)
+      this.writeLengthEncoded(associatedValue, isUnlModifyWorkaround)
     } else {
       associatedValue.toBytesSink(this.sink)
     }
@@ -145,9 +149,15 @@ class BinarySerializer {
    *
    * @param value length encoded value to write to BytesList
    */
-  public writeLengthEncoded(value: SerializedType): void {
+  public writeLengthEncoded(
+    value: SerializedType,
+    isUnlModifyWorkaround = false,
+  ): void {
     const bytes = new BytesList()
-    value.toBytesSink(bytes)
+    if (!isUnlModifyWorkaround) {
+      // this part doesn't happen for the Account field in a UNLModify transaction
+      value.toBytesSink(bytes)
+    }
     this.put(this.encodeVariableLength(bytes.getLength()))
     this.writeBytesList(bytes)
   }

packages/ripple-binary-codec/src/types/st-object.ts

@@ -1,4 +1,4 @@
-import { Field, FieldInstance } from '../enums'
+import { Field, FieldInstance, Bytes } from '../enums'
 import { SerializedType, JsonObject } from './serialized-type'
 import { xAddressToClassicAddress, isValidXAddress } from 'ripple-address-codec'
 import { BinaryParser } from '../serdes/binary-parser'
@@ -96,6 +96,8 @@ class STObject extends SerializedType {
     const list: BytesList = new BytesList()
     const bytes: BinarySerializer = new BinarySerializer(list)
 
+    let isUnlModify = false
+
     const xAddressDecoded = Object.entries(value).reduce((acc, [key, val]) => {
       let handled: JsonObject | undefined = undefined
       if (val && isValidXAddress(val.toString())) {
@@ -125,8 +127,15 @@ class STObject extends SerializedType {
       const associatedValue = field.associatedType.from(
         xAddressDecoded[field.name],
       )
-
-      bytes.writeFieldAndValue(field, associatedValue)
+      if ((associatedValue as unknown as Bytes).name === 'UNLModify') {
+        // triggered when the TransactionType field has a value of 'UNLModify'
+        isUnlModify = true
+      }
+      // true when in the UNLModify pseudotransaction (after the transaction type has been processed) and working with the
+      // Account field
+      // The Account field must not be a part of the UNLModify pseudotransaction encoding, due to a bug in rippled
+      const isUnlModifyWorkaround = field.name == 'Account' && isUnlModify
+      bytes.writeFieldAndValue(field, associatedValue, isUnlModifyWorkaround)
       if (field.type.name === ST_OBJECT) {
         bytes.put(OBJECT_END_MARKER_BYTE)
       }