From 6886881b761b4057401f69827143d7f4ac5daae9 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@pm.me>
Date: Tue, 25 May 2021 21:17:01 +0200
Subject: [PATCH] fix #297 (length not updated) by updating search markers
 properly

---
 src/structs/Item.js    | 13 +++++++++++++
 tests/y-array.tests.js | 29 +++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/src/structs/Item.js b/src/structs/Item.js
index b88407af..b8d58f6a 100644
--- a/src/structs/Item.js
+++ b/src/structs/Item.js
@@ -566,6 +566,19 @@ export class Item extends AbstractStruct {
       this.content.constructor === right.content.constructor &&
       this.content.mergeWith(right.content)
     ) {
+      const searchMarker = /** @type {AbstractType<any>} */ (this.parent)._searchMarker
+      if (searchMarker) {
+        searchMarker.forEach(marker => {
+          if (marker.p === right) {
+            // right is going to be "forgotten" so we need to update the marker
+            marker.p = this
+            // adjust marker index
+            if (!this.deleted) {
+              marker.index -= this.length
+            }
+          }
+        })
+      }
       if (right.keep) {
         this.keep = true
       }
diff --git a/tests/y-array.tests.js b/tests/y-array.tests.js
index f86d3947..23931f4d 100644
--- a/tests/y-array.tests.js
+++ b/tests/y-array.tests.js
@@ -32,6 +32,35 @@ export const testSlice = tc => {
   t.compareArrays(arr.slice(0, 2), [0, 1])
 }
 
+/**
+ * Debugging yjs#297 - a critical bug connected to the search-marker approach
+ *
+ * @param {t.TestCase} tc
+ */
+export const testLengthIssue = tc => {
+  const doc1 = new Y.Doc()
+  const arr = doc1.getArray('array')
+  arr.push([0, 1, 2, 3])
+  arr.delete(0)
+  arr.insert(0, [0])
+  t.assert(arr.length === arr.toArray().length)
+  doc1.transact(() => {
+    arr.delete(1)
+    t.assert(arr.length === arr.toArray().length)
+    arr.insert(1, [1])
+    t.assert(arr.length === arr.toArray().length)
+    arr.delete(2)
+    t.assert(arr.length === arr.toArray().length)
+    arr.insert(2, [2])
+    t.assert(arr.length === arr.toArray().length)
+  })
+  t.assert(arr.length === arr.toArray().length)
+  arr.delete(1)
+  t.assert(arr.length === arr.toArray().length)
+  arr.insert(1, [1])
+  t.assert(arr.length === arr.toArray().length)
+}
+
 /**
  * @param {t.TestCase} tc
  */