From fe48efe64f07b9d98aecc63c2234230d2fb1a76a Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@protonmail.com>
Date: Thu, 9 Mar 2023 13:44:52 +0100
Subject: [PATCH] fix generating too many cleanup transactions. closes #506

---
 src/types/YXmlFragment.js |  3 ++-
 src/utils/Transaction.js  | 11 +++++++++--
 tests/doc.tests.js        | 18 ++++++++++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/types/YXmlFragment.js b/src/types/YXmlFragment.js
index b229a4ac..06b1c0de 100644
--- a/src/types/YXmlFragment.js
+++ b/src/types/YXmlFragment.js
@@ -257,7 +257,8 @@ export class YXmlFragment extends AbstractType {
    * @return {string} The string representation of all children.
    */
   toString () {
-    return typeListMap(this, xml => xml.toString()).join('')
+    // toString can result in many cleanup transactions. We wrap all cleanup transactions here to reduce the work
+    return transact(/** @type {Doc} */ (this.doc), () => typeListMap(this, xml => xml.toString()).join(''))
   }
 
   /**
diff --git a/src/utils/Transaction.js b/src/utils/Transaction.js
index f6a1179a..1e553a90 100644
--- a/src/utils/Transaction.js
+++ b/src/utils/Transaction.js
@@ -376,15 +376,21 @@ const cleanupTransactions = (transactionCleanups, i) => {
 /**
  * Implements the functionality of `y.transact(()=>{..})`
  *
+ * @template T
  * @param {Doc} doc
- * @param {function(Transaction):void} f
+ * @param {function(Transaction):T} f
  * @param {any} [origin=true]
+ * @return {T}
  *
  * @function
  */
 export const transact = (doc, f, origin = null, local = true) => {
   const transactionCleanups = doc._transactionCleanups
   let initialCall = false
+  /**
+   * @type {any}
+   */
+  let result = null
   if (doc._transaction === null) {
     initialCall = true
     doc._transaction = new Transaction(doc, origin, local)
@@ -395,7 +401,7 @@ export const transact = (doc, f, origin = null, local = true) => {
     doc.emit('beforeTransaction', [doc._transaction, doc])
   }
   try {
-    f(doc._transaction)
+    result = f(doc._transaction)
   } finally {
     if (initialCall) {
       const finishCleanup = doc._transaction === transactionCleanups[0]
@@ -413,4 +419,5 @@ export const transact = (doc, f, origin = null, local = true) => {
       }
     }
   }
+  return result
 }
diff --git a/tests/doc.tests.js b/tests/doc.tests.js
index c6211977..e2910a1f 100644
--- a/tests/doc.tests.js
+++ b/tests/doc.tests.js
@@ -2,6 +2,24 @@
 import * as Y from '../src/index.js'
 import * as t from 'lib0/testing'
 
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testAfterTransactionRecursion = _tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment('')
+  ydoc.on('afterTransaction', tr => {
+    if (tr.origin === 'test') {
+      yxml.toJSON()
+    }
+  })
+  ydoc.transact(_tr => {
+    for (let i = 0; i < 15000; i++) {
+      yxml.push([new Y.XmlText('a')])
+    }
+  }, 'test')
+}
+
 /**
  * @param {t.TestCase} _tc
  */