From 004a781a5635ce370f1cbc157512df3a72c76d93 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@pm.me>
Date: Sun, 13 Dec 2020 16:24:43 +0100
Subject: [PATCH] basic merge works. fixes first test #263

---
 src/structs/Item.js  | 21 +++++++++++++--------
 src/utils/updates.js | 15 ++++++++++-----
 2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/src/structs/Item.js b/src/structs/Item.js
index 4e171224..b4c10074 100644
--- a/src/structs/Item.js
+++ b/src/structs/Item.js
@@ -639,16 +639,21 @@ export class Item extends AbstractStruct {
     }
     if (origin === null && rightOrigin === null) {
       const parent = /** @type {AbstractType<any>} */ (this.parent)
-      const parentItem = parent._item
-      if (parentItem === null) {
-        // parent type on y._map
-        // find the correct key
-        const ykey = findRootTypeKey(parent)
+      if (parent.constructor === String) { // this edge case was added by differential updates
         encoder.writeParentInfo(true) // write parentYKey
-        encoder.writeString(ykey)
+        encoder.writeString(parent)
       } else {
-        encoder.writeParentInfo(false) // write parent id
-        encoder.writeLeftID(parentItem.id)
+        const parentItem = parent._item
+        if (parentItem === null) {
+          // parent type on y._map
+          // find the correct key
+          const ykey = findRootTypeKey(parent)
+          encoder.writeParentInfo(true) // write parentYKey
+          encoder.writeString(ykey)
+        } else {
+          encoder.writeParentInfo(false) // write parent id
+          encoder.writeLeftID(parentItem.id)
+        }
       }
       if (parentSub !== null) {
         encoder.writeString(parentSub)
diff --git a/src/utils/updates.js b/src/utils/updates.js
index 827eb9c2..c2285cce 100644
--- a/src/utils/updates.js
+++ b/src/utils/updates.js
@@ -77,7 +77,6 @@ export class LazyStructWriter {
    * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    */
   constructor (encoder) {
-    this.fresh = true
     /**
      * We keep the last written struct around in case we want to
      * merge it with the next written struct.
@@ -107,7 +106,7 @@ export class LazyStructWriter {
  * @param {Array<Uint8Array>} updates
  * @return {Uint8Array}
  */
-export const mergeUpdates = updates => mergeUpdatesV2(updates, UpdateDecoderV1, UpdateEncoderV2)
+export const mergeUpdates = updates => mergeUpdatesV2(updates, UpdateDecoderV1, UpdateEncoderV1)
 
 /**
  * This method is intended to slice any kind of struct and retrieve the right part.
@@ -213,6 +212,10 @@ export const mergeUpdatesV2 = (updates, YDecoder = UpdateDecoderV2, YEncoder = U
       currWrite = { struct: next, offset: 0 }
     }
   }
+  if (currWrite !== null) {
+    writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+    currWrite = null
+  }
   finishLazyStructWriting(lazyStructEncoder)
 
   const dss = updateDecoders.map(decoder => readDeleteSet(decoder))
@@ -233,10 +236,10 @@ export const diffUpdate = (update, sv) => {
  * @param {LazyStructWriter} lazyWriter
  */
 const flushLazyStructWriter = lazyWriter => {
-  if (!lazyWriter.fresh) {
+  if (lazyWriter.written > 0) {
     lazyWriter.clientStructs.push({ written: lazyWriter.written, restEncoder: encoding.toUint8Array(lazyWriter.encoder.restEncoder) })
     lazyWriter.encoder.restEncoder = encoding.createEncoder()
-    lazyWriter.fresh = true
+    lazyWriter.written = 0
   }
 }
 
@@ -247,8 +250,10 @@ const flushLazyStructWriter = lazyWriter => {
  */
 const writeStructToLazyStructWriter = (lazyWriter, struct, offset) => {
   // flush curr if we start another client
-  if (!lazyWriter.fresh && lazyWriter.currClient !== struct.id.client) {
+  if (lazyWriter.written > 0 && lazyWriter.currClient !== struct.id.client) {
     flushLazyStructWriter(lazyWriter)
+  }
+  if (lazyWriter.written === 0) {
     lazyWriter.currClient = struct.id.client
     // write next client
     lazyWriter.encoder.writeClient(struct.id.client)