Merge #4693

4693: Introduce distinct attributes at search time r=irevoire a=Kerollmops

This PR fixes #4611.

### To Do
- [x] Remove the `distinguishableAttributes` settings (not even a commit about that).
- [x] Use the `filterableAttributes` to be able to use the `distinct` parameter at search.
- [x] Work on the errors and make tests.

Co-authored-by: Clément Renault <clement@meilisearch.com>
Co-authored-by: Tamo <tamo@meilisearch.com>

meilisearch/src/analytics/segment_analytics.rs

@@ -597,6 +597,9 @@ pub struct SearchAggregator {
     // every time a request has a filter, this field must be incremented by one
     sort_total_number_of_criteria: usize,
 
+    // distinct
+    distinct: bool,
+
     // filter
     filter_with_geo_radius: bool,
     filter_with_geo_bounding_box: bool,
@@ -672,6 +675,7 @@ impl SearchAggregator {
             show_ranking_score_details,
             filter,
             sort,
+            distinct,
             facets: _,
             highlight_pre_tag,
             highlight_post_tag,
@@ -694,6 +698,8 @@ impl SearchAggregator {
             ret.sort_sum_of_criteria_terms = sort.len();
         }
 
+        ret.distinct = distinct.is_some();
+
         if let Some(ref filter) = filter {
             static RE: Lazy<Regex> = Lazy::new(|| Regex::new("AND | OR").unwrap());
             ret.filter_total_number_of_criteria = 1;
@@ -798,6 +804,7 @@ impl SearchAggregator {
             sort_with_geo_point,
             sort_sum_of_criteria_terms,
             sort_total_number_of_criteria,
+            distinct,
             filter_with_geo_radius,
             filter_with_geo_bounding_box,
             filter_sum_of_criteria_terms,
@@ -855,6 +862,9 @@ impl SearchAggregator {
         self.sort_total_number_of_criteria =
             self.sort_total_number_of_criteria.saturating_add(sort_total_number_of_criteria);
 
+        // distinct
+        self.distinct |= distinct;
+
         // filter
         self.filter_with_geo_radius |= filter_with_geo_radius;
         self.filter_with_geo_bounding_box |= filter_with_geo_bounding_box;
@@ -926,6 +936,7 @@ impl SearchAggregator {
             sort_with_geo_point,
             sort_sum_of_criteria_terms,
             sort_total_number_of_criteria,
+            distinct,
             filter_with_geo_radius,
             filter_with_geo_bounding_box,
             filter_sum_of_criteria_terms,
@@ -983,6 +994,7 @@ impl SearchAggregator {
                     "with_geoPoint": sort_with_geo_point,
                     "avg_criteria_number": format!("{:.2}", sort_sum_of_criteria_terms as f64 / sort_total_number_of_criteria as f64),
                 },
+                "distinct": distinct,
                 "filter": {
                    "with_geoRadius": filter_with_geo_radius,
                    "with_geoBoundingBox": filter_with_geo_bounding_box,
@@ -1095,6 +1107,7 @@ impl MultiSearchAggregator {
                     show_matches_position: _,
                     filter: _,
                     sort: _,
+                    distinct: _,
                     facets: _,
                     highlight_pre_tag: _,
                     highlight_post_tag: _,

meilisearch/src/routes/indexes/facet_search.rs

@@ -124,6 +124,7 @@ impl From<FacetSearchQuery> for SearchQuery {
             show_ranking_score_details: false,
             filter,
             sort: None,
+            distinct: None,
             facets: None,
             highlight_pre_tag: DEFAULT_HIGHLIGHT_PRE_TAG(),
             highlight_post_tag: DEFAULT_HIGHLIGHT_POST_TAG(),

meilisearch/src/routes/indexes/search.rs

@@ -63,6 +63,8 @@ pub struct SearchQueryGet {
     filter: Option<String>,
     #[deserr(default, error = DeserrQueryParamError<InvalidSearchSort>)]
     sort: Option<String>,
+    #[deserr(default, error = DeserrQueryParamError<InvalidSearchDistinct>)]
+    distinct: Option<String>,
     #[deserr(default, error = DeserrQueryParamError<InvalidSearchShowMatchesPosition>)]
     show_matches_position: Param<bool>,
     #[deserr(default, error = DeserrQueryParamError<InvalidSearchShowRankingScore>)]
@@ -161,6 +163,7 @@ impl From<SearchQueryGet> for SearchQuery {
             attributes_to_highlight: other.attributes_to_highlight.map(|o| o.into_iter().collect()),
             filter,
             sort: other.sort.map(|attr| fix_sort_query_parameters(&attr)),
+            distinct: other.distinct,
             show_matches_position: other.show_matches_position.0,
             show_ranking_score: other.show_ranking_score.0,
             show_ranking_score_details: other.show_ranking_score_details.0,

meilisearch/src/search.rs

@@ -78,6 +78,8 @@ pub struct SearchQuery {
     pub filter: Option<Value>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchSort>)]
     pub sort: Option<Vec<String>>,
+    #[deserr(default, error = DeserrJsonError<InvalidSearchDistinct>)]
+    pub distinct: Option<String>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchFacets>)]
     pub facets: Option<Vec<String>>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchHighlightPreTag>, default = DEFAULT_HIGHLIGHT_PRE_TAG())]
@@ -153,6 +155,7 @@ impl fmt::Debug for SearchQuery {
             show_ranking_score_details,
             filter,
             sort,
+            distinct,
             facets,
             highlight_pre_tag,
             highlight_post_tag,
@@ -202,6 +205,9 @@ impl fmt::Debug for SearchQuery {
         if let Some(sort) = sort {
             debug.field("sort", &sort);
         }
+        if let Some(distinct) = distinct {
+            debug.field("distinct", &distinct);
+        }
         if let Some(facets) = facets {
             debug.field("facets", &facets);
         }
@@ -395,6 +401,8 @@ pub struct SearchQueryWithIndex {
     pub filter: Option<Value>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchSort>)]
     pub sort: Option<Vec<String>>,
+    #[deserr(default, error = DeserrJsonError<InvalidSearchDistinct>)]
+    pub distinct: Option<String>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchFacets>)]
     pub facets: Option<Vec<String>>,
     #[deserr(default, error = DeserrJsonError<InvalidSearchHighlightPreTag>, default = DEFAULT_HIGHLIGHT_PRE_TAG())]
@@ -431,6 +439,7 @@ impl SearchQueryWithIndex {
             show_matches_position,
             filter,
             sort,
+            distinct,
             facets,
             highlight_pre_tag,
             highlight_post_tag,
@@ -459,6 +468,7 @@ impl SearchQueryWithIndex {
                 show_matches_position,
                 filter,
                 sort,
+                distinct,
                 facets,
                 highlight_pre_tag,
                 highlight_post_tag,
@@ -729,6 +739,10 @@ fn prepare_search<'t>(
         search.ranking_score_threshold(ranking_score_threshold.0);
     }
 
+    if let Some(distinct) = &query.distinct {
+        search.distinct(distinct.clone());
+    }
+
     match search_kind {
         SearchKind::KeywordOnly => {
             if let Some(q) = &query.q {
@@ -882,6 +896,7 @@ pub fn perform_search(
         matching_strategy: _,
         attributes_to_search_on: _,
         filter: _,
+        distinct: _,
     } = query;
 
     let format = AttributesFormat {