[diff] add equals/hashCode to ListSelection

GitOrigin-RevId: 01959b04b145db98b2ba973c31ccad04ed62a2bd

platform/diff-api/api-dump.txt

@@ -576,9 +576,11 @@ f:com.intellij.openapi.ListSelection
 - s:createAt(java.util.List,I):com.intellij.openapi.ListSelection
 - s:createSingleton(java.lang.Object):com.intellij.openapi.ListSelection
 - s:empty():com.intellij.openapi.ListSelection
+- equals(java.lang.Object):Z
 - getExplicitSelection():java.util.List
 - getList():java.util.List
 - getSelectedIndex():I
+- hashCode():I
 - isEmpty():Z
 - isExplicitSelection():Z
 - map(com.intellij.util.NullableFunction):com.intellij.openapi.ListSelection

platform/diff-api/src/com/intellij/openapi/ListSelection.java

@@ -7,10 +7,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 /**
  * Utility class used to preserve index during 'map' operations
@@ -122,4 +119,18 @@ public final class ListSelection<T> {
   public boolean isExplicitSelection() {
     return myExplicitSelection;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (!(o instanceof ListSelection<?> selection)) return false;
+    return mySelectedIndex == selection.mySelectedIndex &&
+           myExplicitSelection == selection.myExplicitSelection &&
+           Objects.equals(myList, selection.myList);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(myList, mySelectedIndex, myExplicitSelection);
+  }
 }