first working version that also considers holes in document updates - #263

src/structs/GC.js

@@ -22,6 +22,9 @@ export class GC extends AbstractStruct {
    * @return {boolean}
    */
   mergeWith (right) {
+    if (this.constructor !== right.constructor) {
+      return false
+    }
     this.length += right.length
     return true
   }

src/structs/Item.js

@@ -554,6 +554,7 @@ export class Item extends AbstractStruct {
    */
   mergeWith (right) {
     if (
+      this.constructor === right.constructor &&
       compareIDs(right.origin, this.lastId) &&
       this.right === right &&
       compareIDs(this.rightOrigin, right.rightOrigin) &&
@@ -675,7 +676,7 @@ export const readItemContent = (decoder, info) => contentRefs[info & binary.BITS
  * @type {Array<function(AbstractUpdateDecoder):AbstractContent>}
  */
 export const contentRefs = [
-  () => { throw error.unexpectedCase() }, // GC is not ItemContent
+  () => { error.unexpectedCase() }, // GC is not ItemContent
   readContentDeleted, // 1
   readContentJSON, // 2
   readContentBinary, // 3
@@ -684,7 +685,8 @@ export const contentRefs = [
   readContentFormat, // 6
   readContentType, // 7
   readContentAny, // 8
-  readContentDoc // 9
+  readContentDoc, // 9
+  () => { error.unexpectedCase() } // 10 - Skip is not ItemContent
 ]
 
 /**