From 0a3158ce741989c1e182529fe46d17194e2d82c6 Mon Sep 17 00:00:00 2001
From: Thomas Goyne <tg@realm.io>
Date: Mon, 21 Mar 2016 11:15:29 -0700
Subject: [PATCH] Fix marking deletions when chaining move_last_over()

---
 src/collection_notifications.cpp    | 14 ++++++++++++--
 tests/collection_change_indices.cpp |  9 +++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/collection_notifications.cpp b/src/collection_notifications.cpp
index 3fd03df7..5e95e6be 100644
--- a/src/collection_notifications.cpp
+++ b/src/collection_notifications.cpp
@@ -292,8 +292,17 @@ void CollectionChangeBuilder::move_over(size_t row_ndx, size_t last_row)
         move.to = row_ndx;
         updated_existing_move = true;
 
-        insertions.erase_at(last_row);
-        insertions.insert_at(row_ndx);
+        if (!insertions.empty()) {
+            REALM_ASSERT(std::prev(insertions.end())->second - 1 <= last_row);
+            insertions.remove(last_row);
+        }
+
+        // Don't mark the moved-over row as deleted if it was a new insertion
+        if (!insertions.contains(row_ndx)) {
+            deletions.add_shifted(insertions.unshift(row_ndx));
+            insertions.add(row_ndx);
+        }
+
         // Because this is a move, the unshifted source row has already been marked as deleted
     }
 
@@ -312,6 +321,7 @@ void CollectionChangeBuilder::move_over(size_t row_ndx, size_t last_row)
         deletions.add_shifted(insertions.unshift(row_ndx));
         insertions.add(row_ndx);
     }
+    verify();
 }
 
 void CollectionChangeBuilder::verify()
diff --git a/tests/collection_change_indices.cpp b/tests/collection_change_indices.cpp
index 8526fd07..fcf15e75 100644
--- a/tests/collection_change_indices.cpp
+++ b/tests/collection_change_indices.cpp
@@ -185,6 +185,15 @@ TEST_CASE("[collection_change] move_over()") {
         REQUIRE_INDICES(c.insertions, 5, 6);
         REQUIRE_MOVES(c, {10, 5}, {9, 6});
     }
+
+    SECTION("marks the moved-over row as deleted when chaining moves") {
+        c.move_over(5, 10);
+        c.move_over(0, 5);
+
+        REQUIRE_INDICES(c.deletions, 0, 5, 10);
+        REQUIRE_INDICES(c.insertions, 0);
+        REQUIRE_MOVES(c, {10, 0});
+    }
 }
 
 TEST_CASE("[collection_change] clear()") {