From 6291c0401676205f0678b4f9afc19d0e795d9971 Mon Sep 17 00:00:00 2001
From: Vladislav <vlad@dragonflydb.io>
Date: Mon, 17 Jun 2024 23:39:38 +0300
Subject: [PATCH] chore(search): Add __vector_score alias (#3186)

---
 src/core/search/search.cc               | 2 +-
 src/server/search/search_family_test.cc | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/core/search/search.cc b/src/core/search/search.cc
index 525a06dce..ca01c3916 100644
--- a/src/core/search/search.cc
+++ b/src/core/search/search.cc
@@ -319,7 +319,7 @@ struct BasicSearch {
 
     // Skip sorting again for KNN queries, reverse if needed will be applied on aggregation
     if (auto knn = get_if<AstKnnNode>(&node.filter->Variant());
-        knn && knn->score_alias == node.field) {
+        knn && (knn->score_alias == node.field || "__vector_score" == node.field)) {
       return sub_results;
     }
 
diff --git a/src/server/search/search_family_test.cc b/src/server/search/search_family_test.cc
index da12a1aa1..7d86bf84f 100644
--- a/src/server/search/search_family_test.cc
+++ b/src/server/search/search_family_test.cc
@@ -455,8 +455,14 @@ TEST_F(SearchFamilyTest, TestReturn) {
   resp = Run({"ft.search", "i1", "@justA:0", "return", "1", "nothere"});
   EXPECT_THAT(resp, MatchEntry("k0", "nothere", ""));
 
+  // Checl implcit __vector_score is provided
+  float score = 20;
+  resp = Run({"ft.search", "i1", "@justA:0 => [KNN 20 @vector $vector]", "SORTBY", "__vector_score",
+              "DESC", "RETURN", "1", "longA", "PARAMS", "2", "vector", floatsv(&score)});
+  EXPECT_THAT(resp, MatchEntry("k0", "longA", "0"));
+
   // Check sort doesn't shadow knn return alias
-  const float score = 20;
+  score = 20;
   resp = Run({"ft.search", "i1", "@justA:0 => [KNN 20 @vector $vector AS vec_return]", "SORTBY",
               "vec_return", "DESC", "RETURN", "1", "vec_return", "PARAMS", "2", "vector",
               floatsv(&score)});