From d2e1e90f948a9ec76696211116cc5e77b9e37d14 Mon Sep 17 00:00:00 2001
From: Dmitry Bushev <bushevdv@gmail.com>
Date: Wed, 4 Dec 2024 21:05:12 +0300
Subject: [PATCH] Compute correct changeset when swapping nodes (#11765)

close #11734

The #11428 introduced a special handling of edits removing the node. This logic is also triggered when the GUI swaps two lines leading to computing incorrect changeset.

Changelog:
- update: correct the logic that determines if the edit removes a line

# Important Notes
https://github.com/user-attachments/assets/fa84bb09-5f86-4739-b447-e49c49a09a76
---
 .../instrument/ChangesetBuilder.scala         | 21 ++++++++---
 .../test/context/ChangesetBuilderTest.scala   | 35 +++++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/engine/runtime-instrument-common/src/main/scala/org/enso/interpreter/instrument/ChangesetBuilder.scala b/engine/runtime-instrument-common/src/main/scala/org/enso/interpreter/instrument/ChangesetBuilder.scala
index 8f6b45f1d9..587403c874 100644
--- a/engine/runtime-instrument-common/src/main/scala/org/enso/interpreter/instrument/ChangesetBuilder.scala
+++ b/engine/runtime-instrument-common/src/main/scala/org/enso/interpreter/instrument/ChangesetBuilder.scala
@@ -12,6 +12,7 @@ import org.enso.text.editing.model.{IdMap, TextEdit}
 import org.enso.text.editing.{IndexedSource, TextEditor}
 
 import java.util.UUID
+
 import scala.collection.mutable
 
 /** The changeset of a module containing the computed list of invalidated
@@ -178,6 +179,8 @@ final class ChangesetBuilder[A: TextEditor: IndexedSource](
     * @return the set of IR nodes directly affected by the edit
     */
   def invalidated(edits: Seq[TextEdit]): Set[ChangesetBuilder.NodeId] = {
+    val allEdits = edits.toSet
+
     @scala.annotation.tailrec
     def go(
       tree: ChangesetBuilder.Tree,
@@ -187,8 +190,9 @@ final class ChangesetBuilder[A: TextEditor: IndexedSource](
     ): Set[ChangesetBuilder.NodeId] = {
       if (edits.isEmpty) ids.toSet
       else {
-        val edit         = edits.dequeue()
-        val locationEdit = ChangesetBuilder.toLocationEdit(edit, source)
+        val edit = edits.dequeue()
+        val locationEdit =
+          ChangesetBuilder.toLocationEdit(edit, source, allEdits)
         var invalidatedSet =
           ChangesetBuilder.invalidated(
             tree,
@@ -533,17 +537,26 @@ object ChangesetBuilder {
     *
     * @param edit the text edit
     * @param source the source text
+    * @param edits all applied text edits
     * @return the edit location in the source text
     */
   private def toLocationEdit[A: IndexedSource](
     edit: TextEdit,
-    source: A
+    source: A,
+    edits: Set[TextEdit]
   ): LocationEdit = {
     def isSameOffset: Boolean =
       edit.range.end.character == edit.range.start.character
     def isAcrossLines: Boolean =
       edit.range.end.line > edit.range.start.line
-    val isNodeRemoved = edit.text.isEmpty && isSameOffset && isAcrossLines
+    def otherEditPositions =
+      (edits - edit).flatMap(edit => Set(edit.range.start, edit.range.end))
+    def noOtherEditsOnTheLine =
+      !otherEditPositions.exists(p =>
+        p.line == edit.range.start.line || p.line == edit.range.end.line
+      )
+    val isNodeRemoved =
+      edit.text.isEmpty && isSameOffset && isAcrossLines && noOtherEditsOnTheLine
     LocationEdit(toLocation(edit, source), edit.text.length, isNodeRemoved)
   }
 
diff --git a/engine/runtime-instrument-common/src/test/scala/org/enso/compiler/test/context/ChangesetBuilderTest.scala b/engine/runtime-instrument-common/src/test/scala/org/enso/compiler/test/context/ChangesetBuilderTest.scala
index 76015824f6..389deeae91 100644
--- a/engine/runtime-instrument-common/src/test/scala/org/enso/compiler/test/context/ChangesetBuilderTest.scala
+++ b/engine/runtime-instrument-common/src/test/scala/org/enso/compiler/test/context/ChangesetBuilderTest.scala
@@ -242,6 +242,41 @@ class ChangesetBuilderTest
       )
     }
 
+    "multiline swap nodes" in {
+      val code =
+        """x ->
+          |    y = _.abs
+          |    z = 42
+          |    y + x""".stripMargin.linesIterator.mkString("\n")
+      val edits = Seq(
+        TextEdit(Range(Position(1, 4), Position(2, 4)), ""),
+        TextEdit(Range(Position(2, 0), Position(2, 0)), "    y = z.abs\n")
+      )
+
+      val ir = code
+        .preprocessExpression(freshInlineContext)
+        .get
+        .asInstanceOf[Function.Lambda]
+
+      val firstLine = ir.body.children()(0).asInstanceOf[Expression.Binding]
+      val yName     = firstLine.name
+      val yExpr = firstLine.expression
+        .asInstanceOf[Function.Lambda]
+        .body
+        .asInstanceOf[Application.Prefix]
+      val yExprFunction    = yExpr.function
+      val yExprFunctionArg = yExpr.arguments(0).value
+      val secondLine       = ir.body.children()(1).asInstanceOf[Expression.Binding]
+      val zName            = secondLine.name
+
+      invalidated(ir, code, edits: _*) should contain theSameElementsAs Seq(
+        yName.getId,
+        yExprFunction.getId,
+        yExprFunctionArg.getId,
+        zName.getId
+      )
+    }
+
     "multiline insert line 1" in {
       val code =
         """x ->