feat(search): update nbHits count with filtered docs for placeholder search

meilisearch-core/src/query_builder.rs

@@ -225,10 +225,17 @@ impl<'c, 'f, 'd, 'i> QueryBuilder<'c, 'f, 'd, 'i> {
 
     fn sort_result_from_docids(&self, docids: &[DocumentId], range: Range<usize>) -> SortResult {
         let mut sort_result = SortResult::default();
+        let mut filtered_count = 0;
         let mut result = match self.filter {
             Some(ref filter) => docids
                 .iter()
-                .filter(|item| (filter)(**item))
+                .filter(|item| {
+                    let accepted = (filter)(**item);
+                    if !accepted {
+                        filtered_count += 1;
+                    }
+                    accepted
+                })
                 .skip(range.start)
                 .take(range.end - range.start)
                 .map(|&id| Document::from_highlights(id, &[]))
@@ -248,15 +255,19 @@ impl<'c, 'f, 'd, 'i> QueryBuilder<'c, 'f, 'd, 'i> {
             result.retain(|doc| {
                 let id = doc.id;
                 let key = (distinct)(id);
-                match key {
+                let distinct_accepted = match key {
                     Some(key) => distinct_map.register(key),
                     None => distinct_map.register_without_key(),
+                };
+                if !distinct_accepted {
+                    filtered_count += 1;
                 }
+                distinct_accepted
             });
         }
 
         sort_result.documents = result;
-        sort_result.nb_hits = docids.len();
+        sort_result.nb_hits = docids.len() - filtered_count;
         sort_result
     }
 

meilisearch-http/tests/placeholder_search.rs

@@ -588,3 +588,48 @@ async fn placeholder_search_with_empty_query() {
         assert_eq!(response["hits"].as_array().unwrap().len(), 3);
     });
 }
+
+#[actix_rt::test]
+async fn test_filter_nb_hits_search_placeholder() {
+    let mut server = common::Server::with_uid("test");
+
+    let body = json!({
+        "uid": "test",
+        "primaryKey": "id",
+    });
+
+    server.create_index(body).await;
+    let documents = json!([
+        {
+            "id": 1,
+            "content": "a",
+            "color": "green",
+            "size": 1,
+        },
+        {
+            "id": 2,
+            "content": "a",
+            "color": "green",
+            "size": 2,
+        },
+        {
+            "id": 3,
+            "content": "a",
+            "color": "blue",
+            "size": 3,
+        },
+    ]);
+
+    server.add_or_update_multiple_documents(documents).await;
+    let (response, _) = server.search_post(json!({})).await;
+    assert_eq!(response["nbHits"], 3);
+
+    server.update_distinct_attribute(json!("color")).await;
+
+    let (response, _) = server.search_post(json!({})).await;
+    assert_eq!(response["nbHits"], 2);
+
+    let (response, _) = server.search_post(json!({"filters": "size < 3"})).await;
+    println!("result: {}", response);
+    assert_eq!(response["nbHits"], 1);
+}