From 23bfd7f4fca4eb29aaff4c21404c357b7b10b450 Mon Sep 17 00:00:00 2001
From: jeremy <jeremy.bailleux@memgraph.io>
Date: Thu, 1 Dec 2022 13:45:24 +0100
Subject: [PATCH] Updated OnceCursor

---
 src/query/v2/multiframe.cpp    |  5 +++++
 src/query/v2/multiframe.hpp    |  7 +++++++
 src/query/v2/plan/operator.cpp | 11 ++++-------
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/query/v2/multiframe.cpp b/src/query/v2/multiframe.cpp
index 27b0872ed..74ccf8478 100644
--- a/src/query/v2/multiframe.cpp
+++ b/src/query/v2/multiframe.cpp
@@ -41,6 +41,11 @@ MultiFrame::MultiFrame(const MultiFrame &other) {
 // NOLINTNEXTLINE (bugprone-exception-escape)
 MultiFrame::MultiFrame(MultiFrame &&other) noexcept : frames_(std::move(other.frames_)) {}
 
+FrameWithValidity &MultiFrame::GetFirstFrame() {
+  MG_ASSERT(!frames_.empty());
+  return frames_.front();
+}
+
 void MultiFrame::MakeAllFramesInvalid() noexcept {
   std::for_each(frames_.begin(), frames_.end(), [](auto &frame) { frame.MakeInvalid(); });
 }
diff --git a/src/query/v2/multiframe.hpp b/src/query/v2/multiframe.hpp
index 7c0f366eb..e76f34c5a 100644
--- a/src/query/v2/multiframe.hpp
+++ b/src/query/v2/multiframe.hpp
@@ -71,6 +71,13 @@ class MultiFrame {
    */
   InvalidFramesPopulator GetInvalidFramesPopulator();
 
+  /**
+   * Return the first Frame of the MultiFrame. This is only meant to be used in very specific cases. Please consider
+   * using the iterators instead.
+   * The Frame can be valid or invalid.
+   */
+  FrameWithValidity &GetFirstFrame();
+
   void MakeAllFramesInvalid() noexcept;
 
   bool HasValidFrame() const noexcept;
diff --git a/src/query/v2/plan/operator.cpp b/src/query/v2/plan/operator.cpp
index c9fd05609..9a000face 100644
--- a/src/query/v2/plan/operator.cpp
+++ b/src/query/v2/plan/operator.cpp
@@ -267,14 +267,11 @@ bool Once::OnceCursor::Pull(Frame &, ExecutionContext &context) {
 void Once::OnceCursor::PullMultiple(MultiFrame &multi_frame, ExecutionContext &context) {
   SCOPED_PROFILE_OP("OnceMF");
 
-  auto iterator_for_valid_frame_only = multi_frame.GetValidFramesConsumer();
-  auto first_it = iterator_for_valid_frame_only.begin();
-  MG_ASSERT(first_it != iterator_for_valid_frame_only.end());
   if (!did_pull_) {
-    auto *memory_resource = multi_frame.GetMemoryResource();
-    auto &frame = *first_it;
-    frame.MakeValid();
-    for (auto &value : frame.elems()) {
+    auto &first_frame = multi_frame.GetFirstFrame();
+    auto *memory_resource = first_frame.GetMemoryResource();
+    first_frame.MakeValid();
+    for (auto &value : first_frame.elems()) {
       value = TypedValue{memory_resource};
     }
     did_pull_ = true;