From e44e7b5e81e8644ae1c95d3a3b28f530fcc52eb2 Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Mon, 14 Oct 2024 16:17:19 +0200
Subject: [PATCH 1/2] Fix retrieveVectors when explicitly passed in displayed
 attributes without any document containing _vectors

---
 meilisearch/src/search/mod.rs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/meilisearch/src/search/mod.rs b/meilisearch/src/search/mod.rs
index 66b6e56de..7832c1761 100644
--- a/meilisearch/src/search/mod.rs
+++ b/meilisearch/src/search/mod.rs
@@ -1195,8 +1195,13 @@ impl<'a> HitMaker<'a> {
         let vectors_is_hidden = match (&displayed_ids, vectors_fid) {
             // displayed_ids is a wildcard, so `_vectors` can be displayed regardless of its fid
             (None, _) => false,
-            // displayed_ids is a finite list, and `_vectors` cannot be part of it because it is not an existing field
-            (Some(_), None) => true,
+            // vectors has no fid, so check its explicit name
+            (Some(_), None) => {
+                // unwrap as otherwise we'd go to the first one
+                let displayed_names = index.displayed_fields(rtxn)?.unwrap();
+                !displayed_names
+                    .contains(&milli::vector::parsed_vectors::RESERVED_VECTORS_FIELD_NAME)
+            }
             // displayed_ids is a finit list, so hide if `_vectors` is not part of it
             (Some(map), Some(vectors_fid)) => map.contains(&vectors_fid),
         };

From 5a74d4729cdc02a3cea011d4ab6a0f608be867f9 Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Mon, 14 Oct 2024 16:23:28 +0200
Subject: [PATCH 2/2] Add test failing before this PR, OK now

---
 meilisearch/tests/search/hybrid.rs | 51 ++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/meilisearch/tests/search/hybrid.rs b/meilisearch/tests/search/hybrid.rs
index e301c0b05..00a65d9aa 100644
--- a/meilisearch/tests/search/hybrid.rs
+++ b/meilisearch/tests/search/hybrid.rs
@@ -568,6 +568,57 @@ async fn retrieve_vectors() {
     ]
     "###);
 
+    // use explicit `_vectors` in displayed attributes
+    let (response, code) = index
+        .update_settings(json!({ "displayedAttributes": ["id", "title", "desc", "_vectors"]} ))
+        .await;
+    assert_eq!(202, code, "{:?}", response);
+    index.wait_task(response.uid()).await;
+
+    let (response, code) = index
+        .search_post(
+            json!({"q": "Captain", "hybrid": {"embedder": "default", "semanticRatio": 0.2}, "retrieveVectors": true}),
+        )
+        .await;
+    snapshot!(code, @"200 OK");
+    insta::assert_json_snapshot!(response["hits"], {"[]._vectors.default.embeddings" => "[vectors]"},  @r###"
+    [
+      {
+        "title": "Captain Planet",
+        "desc": "He's not part of the Marvel Cinematic Universe",
+        "id": "2",
+        "_vectors": {
+          "default": {
+            "embeddings": "[vectors]",
+            "regenerate": true
+          }
+        }
+      },
+      {
+        "title": "Captain Marvel",
+        "desc": "a Shazam ersatz",
+        "id": "3",
+        "_vectors": {
+          "default": {
+            "embeddings": "[vectors]",
+            "regenerate": true
+          }
+        }
+      },
+      {
+        "title": "Shazam!",
+        "desc": "a Captain Marvel ersatz",
+        "id": "1",
+        "_vectors": {
+          "default": {
+            "embeddings": "[vectors]",
+            "regenerate": true
+          }
+        }
+      }
+    ]
+    "###);
+
     // remove `_vectors` from displayed attributes
     let (response, code) =
         index.update_settings(json!({ "displayedAttributes": ["id", "title", "desc"]} )).await;