Fix serializedobject append for excessively large bytes length

src/serializedobject.js

@@ -137,13 +137,18 @@ SerializedObject.prototype.append = function(bytes) {
     bytes = bytes.buffer;
   }
 
-  // Make sure both buffer and bytes are Array. Either could potentially be a
-  // Buffer.
+  // Make sure both buffer and bytes are Array. Either could be a Buffer.
   if (Array.isArray(this.buffer) && Array.isArray(bytes)) {
-    // Array::concat is horribly slow where buffer length is 100 kbytes + One
-    // transaction with 1100 affected nodes took around 23 seconds to convert
-    // from json to bytes.
-    Array.prototype.push.apply(this.buffer, bytes);
+    // `this.buffer = this.buffer.concat(bytes)` can be unbearably slow for
+    // large bytes length and acceptable bytes length is limited for
+    // `Array.prototype.push.apply(this.buffer, bytes)` as every element in the
+    // bytes array is pushed onto the stack, potentially causing a RangeError
+    // exception. Both of these solutions are known to be problematic for
+    // ledger 7501326. KISS instead
+
+    for (var i = 0; i < bytes.length; i++) {
+      this.buffer.push(bytes[i]);
+    }
   } else {
     this.buffer = this.buffer.concat(bytes);
   }

test/ledger-test.js

@@ -7,7 +7,7 @@ var Ledger = require('ripple-lib').Ledger;
 * @param ledger_index {Number}
 * Expects a corresponding ledger dump in $repo/test/fixtures/ folder
 */
-create_ledger_test = function (ledger_index) {
+create_ledger_test = function (ledger_index, no_accounts) {
   describe(String(ledger_index), function() {
 
     var path = __dirname + '/fixtures/ledger-full-'+ledger_index+'.json';
@@ -16,10 +16,12 @@ create_ledger_test = function (ledger_index) {
         ledger_json  = JSON.parse(ledger_raw),
         ledger       = Ledger.from_json(ledger_json);
 
-    it('has account_hash of '+ ledger_json.account_hash, function() {
-      assert.equal(ledger_json.account_hash,
-                   ledger.calc_account_hash({sanity_test:true}).to_hex());
-    })
+    if (!no_accounts) {
+      it('has account_hash of '+ ledger_json.account_hash, function() {
+        assert.equal(ledger_json.account_hash,
+                     ledger.calc_account_hash({sanity_test:true}).to_hex());
+      })
+    }
     it('has transaction_hash of '+ ledger_json.transaction_hash, function() {
       assert.equal(ledger_json.transaction_hash,
                    ledger.calc_tx_hash().to_hex());
@@ -32,6 +34,8 @@ describe('Ledger', function() {
   create_ledger_test(38129);
   // Because, why not.
   create_ledger_test(40000);
+  // 1311 AffectedNodes, no accounts
+  create_ledger_test(7501326, true);
 
   describe('#calcAccountRootEntryHash', function () {
     it('will calculate the AccountRoot entry hash for rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh', function () {