From 3b4ed65b940c38f19ac503df1cb976c41a86aba0 Mon Sep 17 00:00:00 2001
From: Michael MacFadden <michael@convergencelabs.com>
Date: Fri, 4 Feb 2022 11:59:37 -0600
Subject: [PATCH] Update the string splice transform logic

Fixes convergencelabs/convergence-project#264
---
 .../xform/string/StringSpliceSpliceTF.scala   | 17 +++++++----
 ...ng-splice-replace-splice-replace-spec.json | 28 +++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)
 create mode 100644 src/test/otfspec/otf-string-splice-replace-splice-replace-spec.json

diff --git a/src/main/scala/com/convergencelabs/convergence/server/backend/services/domain/model/ot/xform/string/StringSpliceSpliceTF.scala b/src/main/scala/com/convergencelabs/convergence/server/backend/services/domain/model/ot/xform/string/StringSpliceSpliceTF.scala
index da3e1365..7afd9017 100644
--- a/src/main/scala/com/convergencelabs/convergence/server/backend/services/domain/model/ot/xform/string/StringSpliceSpliceTF.scala
+++ b/src/main/scala/com/convergencelabs/convergence/server/backend/services/domain/model/ot/xform/string/StringSpliceSpliceTF.scala
@@ -391,14 +391,21 @@ private[ot] object StringSpliceSpliceTF extends OperationTransformationFunction[
       case FinishedBy =>
         (
           s.copy(deleteCount = s.deleteCount - c.deleteCount),
-          c.copy(deleteCount = 0, index = s.index + s.insertValue.length),
+          c.copy(deleteCount = 0, index = s.index + s.insertValue.length)
         )
 
       case EqualTo =>
-        (
-          s.copy(deleteCount = 0),
-          c.copy(index = c.index + s.insertValue.length, deleteCount = 0),
-        )
+        if (s.insertValue != c.insertValue) {
+          (
+            s,
+            c.copy(noOp = true)
+          )
+        } else {
+          (
+            s.copy(noOp = true),
+            c.copy(noOp = true)
+          )
+        }
     }
   }
 
diff --git a/src/test/otfspec/otf-string-splice-replace-splice-replace-spec.json b/src/test/otfspec/otf-string-splice-replace-splice-replace-spec.json
new file mode 100644
index 00000000..059e3dee
--- /dev/null
+++ b/src/test/otfspec/otf-string-splice-replace-splice-replace-spec.json
@@ -0,0 +1,28 @@
+{
+  "serverOpType": "StringSplice",
+  "clientOpType": "StringSplice",
+  "cases": [
+    {
+      "id": "S-PP-1",
+      "input": {
+        "serverOp": {"type": "StringSplice", "noOp": false, "index": 4, "deleteCount": 1, "insertValue": "X"},
+        "clientOp": {"type": "StringSplice", "noOp": false, "index": 4, "deleteCount": 1, "insertValue": "Y"}
+      },
+      "output": {
+        "serverOp": {"type": "StringSplice", "noOp": false, "index": 4, "deleteCount": 1, "insertValue": "X"},
+        "clientOp": {"type": "StringSplice", "noOp": true, "index": 4, "deleteCount": 1, "insertValue": "Y"}
+      }
+    },
+    {
+      "id": "S-PP-2",
+      "input": {
+        "serverOp": {"type": "StringSplice", "noOp": false, "index": 4, "deleteCount": 1, "insertValue": "X"},
+        "clientOp": {"type": "StringSplice", "noOp": false, "index": 4, "deleteCount": 1, "insertValue": "X"}
+      },
+      "output": {
+        "serverOp": {"type": "StringSplice", "noOp": true, "index": 4, "deleteCount": 1, "insertValue": "X"},
+        "clientOp": {"type": "StringSplice", "noOp": true, "index": 4, "deleteCount": 1, "insertValue": "X"}
+      }
+    }
+  ]
+}
\ No newline at end of file