From fddf2e54e99ad13e6a7293ba937f0e98cbaeb2ac Mon Sep 17 00:00:00 2001
From: Tyera Eulberg <tyera@solana.com>
Date: Fri, 30 Aug 2019 17:22:11 -0600
Subject: [PATCH] fix: enable serialization of unsigned transactions

---
 web3.js/src/transaction.js       |  37 +++--
 web3.js/test/transaction.test.js | 234 +++++++++++++++++++++++++++++++
 2 files changed, 256 insertions(+), 15 deletions(-)

diff --git a/web3.js/src/transaction.js b/web3.js/src/transaction.js
index f618d66fb9..510814a5dc 100644
--- a/web3.js/src/transaction.js
+++ b/web3.js/src/transaction.js
@@ -16,6 +16,13 @@ import type {Blockhash} from './blockhash';
  */
 export type TransactionSignature = string;
 
+/**
+ * Default (empty) signature
+ *
+ * Signatures are 64 bytes in length
+ */
+const DEFAULT_SIGNATURE = Array(64).fill(0);
+
 /**
  * Maximum over-the-wire size of a Transaction
  *
@@ -164,7 +171,6 @@ export class Transaction {
     }
 
     const keys = this.signatures.map(({publicKey}) => publicKey.toString());
-    let numRequiredSignatures = 0;
     let numCreditOnlySignedAccounts = 0;
     let numCreditOnlyUnsignedAccounts = 0;
 
@@ -175,7 +181,10 @@ export class Transaction {
         const keyStr = keySignerPair.pubkey.toString();
         if (!keys.includes(keyStr)) {
           if (keySignerPair.isSigner) {
-            numRequiredSignatures += 1;
+            this.signatures.push({
+              signature: null,
+              publicKey: keySignerPair.pubkey,
+            });
             if (!keySignerPair.isDebitable) {
               numCreditOnlySignedAccounts += 1;
             }
@@ -201,12 +210,6 @@ export class Transaction {
       }
     });
 
-    if (numRequiredSignatures > this.signatures.length) {
-      throw new Error(
-        `Insufficent signatures: expected ${numRequiredSignatures} but got ${this.signatures.length}`,
-      );
-    }
-
     let keyCount = [];
     shortvec.encodeLength(keyCount, keys.length);
 
@@ -391,12 +394,13 @@ export class Transaction {
     invariant(signatures.length < 256);
     Buffer.from(signatureCount).copy(wireTransaction, 0);
     signatures.forEach(({signature}, index) => {
-      invariant(signature !== null, `null signature`);
-      invariant(signature.length === 64, `signature has invalid length`);
-      Buffer.from(signature).copy(
-        wireTransaction,
-        signatureCount.length + index * 64,
-      );
+      if (signature !== null) {
+        invariant(signature.length === 64, `signature has invalid length`);
+        Buffer.from(signature).copy(
+          wireTransaction,
+          signatureCount.length + index * 64,
+        );
+      }
     });
     signData.copy(
       wireTransaction,
@@ -506,7 +510,10 @@ export class Transaction {
     transaction.recentBlockhash = new PublicKey(recentBlockhash).toBase58();
     for (let i = 0; i < signatureCount; i++) {
       const sigPubkeyPair = {
-        signature: Buffer.from(signatures[i]),
+        signature:
+          signatures[i].toString() == DEFAULT_SIGNATURE.toString()
+            ? null
+            : Buffer.from(signatures[i]),
         publicKey: new PublicKey(accounts[i]),
       };
       transaction.signatures.push(sigPubkeyPair);
diff --git a/web3.js/test/transaction.test.js b/web3.js/test/transaction.test.js
index f63210960d..9856f6fa75 100644
--- a/web3.js/test/transaction.test.js
+++ b/web3.js/test/transaction.test.js
@@ -313,3 +313,237 @@ test('parse wire format and serialize', () => {
   expect(tx).toEqual(expectedTransaction);
   expect(wireTransaction).toEqual(expectedTransaction.serialize());
 });
+
+test('serialize unsigned transaction', () => {
+  const keypair = nacl.sign.keyPair.fromSeed(
+    Uint8Array.from(Array(32).fill(8)),
+  );
+  const sender = new Account(Buffer.from(keypair.secretKey)); // Arbitrary known account
+  const recentBlockhash = 'EETubP5AKHgjPAhzPAFcb8BAY1hMH639CWCFTqi3hq1k'; // Arbitrary known recentBlockhash
+  const recipient = new PublicKey(
+    'J3dxNj7nDRRqRRXuEMynDG57DkZK4jYRuv3Garmb1i99',
+  ); // Arbitrary known public key
+  const transfer = SystemProgram.transfer(sender.publicKey, recipient, 49);
+  const expectedTransaction = new Transaction({recentBlockhash}).add(transfer);
+  const wireTransaction = Buffer.from([
+    1,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    1,
+    0,
+    2,
+    3,
+    19,
+    152,
+    246,
+    44,
+    109,
+    26,
+    69,
+    124,
+    81,
+    186,
+    106,
+    75,
+    95,
+    61,
+    189,
+    47,
+    105,
+    252,
+    169,
+    50,
+    22,
+    33,
+    141,
+    200,
+    153,
+    126,
+    65,
+    107,
+    209,
+    125,
+    147,
+    202,
+    253,
+    67,
+    159,
+    204,
+    182,
+    103,
+    39,
+    242,
+    137,
+    197,
+    198,
+    222,
+    59,
+    196,
+    168,
+    254,
+    93,
+    213,
+    215,
+    119,
+    112,
+    188,
+    143,
+    241,
+    92,
+    62,
+    238,
+    220,
+    177,
+    74,
+    243,
+    252,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    196,
+    154,
+    231,
+    118,
+    3,
+    120,
+    32,
+    84,
+    241,
+    122,
+    157,
+    236,
+    234,
+    67,
+    180,
+    68,
+    235,
+    160,
+    237,
+    177,
+    44,
+    111,
+    29,
+    49,
+    198,
+    224,
+    228,
+    168,
+    75,
+    240,
+    82,
+    235,
+    1,
+    2,
+    2,
+    0,
+    1,
+    12,
+    2,
+    0,
+    0,
+    0,
+    49,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+    0,
+  ]);
+  expect(wireTransaction).toEqual(expectedTransaction.serialize());
+
+  const tx = Transaction.from(wireTransaction);
+  expect(tx).toEqual(expectedTransaction);
+});