From dc8a662209395378dc9a6c17e3f1def3f00a218c Mon Sep 17 00:00:00 2001
From: Louis Dureuil <louis@meilisearch.com>
Date: Tue, 17 Sep 2024 10:08:21 +0200
Subject: [PATCH] federated queries: adjust error message

---
 meilisearch/src/error.rs            |  8 ++++----
 meilisearch/src/search/federated.rs | 10 ++++++++--
 meilisearch/src/search/mod.rs       |  5 ++---
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/meilisearch/src/error.rs b/meilisearch/src/error.rs
index fa315837f..9d5eff016 100644
--- a/meilisearch/src/error.rs
+++ b/meilisearch/src/error.rs
@@ -32,9 +32,9 @@ pub enum MeilisearchHttpError {
     FederationOptionsInNonFederatedRequest(usize),
     #[error("Inside `.queries[{0}]`: Using pagination options is not allowed in federated queries.\n - Hint: remove `{1}` from query #{0} or remove `federation` from the request\n - Hint: pass `federation.limit` and `federation.offset` for pagination in federated search")]
     PaginationInFederatedQuery(usize, &'static str),
-    #[error("Inside `.queries[{0}]`: Using facet options is not allowed in federated queries.\n Hint: remove `facets` from query #{0} or remove `federation` from the request")]
-    FacetsInFederatedQuery(usize),
-    #[error("Inconsistent order for values in facet `{facet}`: index `{previous_uid}` orders {previous_facet_order}, but index `{current_uid}` orders {index_facet_order}.\n Hint: Remove `federation.mergeFacets` or set `federation.mergeFacets.sortFacetValuesBy` to the desired order.")]
+    #[error("Inside `.queries[{0}]`: Using facet options is not allowed in federated queries.\n - Hint: remove `facets` from query #{0} or remove `federation` from the request\n - Hint: pass `federation.facetsByIndex.{1}: {2:?}` for facets in federated search")]
+    FacetsInFederatedQuery(usize, String, Vec<String>),
+    #[error("Inconsistent order for values in facet `{facet}`: index `{previous_uid}` orders {previous_facet_order}, but index `{current_uid}` orders {index_facet_order}.\n - Hint: Remove `federation.mergeFacets` or set `federation.mergeFacets.sortFacetValuesBy` to the desired order.")]
     InconsistentFacetOrder {
         facet: String,
         previous_facet_order: OrderBy,
@@ -107,7 +107,7 @@ impl ErrorCode for MeilisearchHttpError {
             MeilisearchHttpError::PaginationInFederatedQuery(_, _) => {
                 Code::InvalidMultiSearchQueryPagination
             }
-            MeilisearchHttpError::FacetsInFederatedQuery(_) => Code::InvalidMultiSearchQueryFacets,
+            MeilisearchHttpError::FacetsInFederatedQuery(..) => Code::InvalidMultiSearchQueryFacets,
             MeilisearchHttpError::InconsistentFacetOrder { .. } => {
                 Code::InvalidMultiSearchFacetOrder
             }
diff --git a/meilisearch/src/search/federated.rs b/meilisearch/src/search/federated.rs
index 6470002ab..46643556d 100644
--- a/meilisearch/src/search/federated.rs
+++ b/meilisearch/src/search/federated.rs
@@ -513,8 +513,14 @@ pub fn perform_federated_search(
             .into());
         }
 
-        if federated_query.has_facets() {
-            return Err(MeilisearchHttpError::FacetsInFederatedQuery(query_index).into());
+        if let Some(facets) = federated_query.has_facets() {
+            let facets = facets.to_owned();
+            return Err(MeilisearchHttpError::FacetsInFederatedQuery(
+                query_index,
+                federated_query.index_uid.into_inner(),
+                facets,
+            )
+            .into());
         }
 
         let (index_uid, query, federation_options) = federated_query.into_index_query_federation();
diff --git a/meilisearch/src/search/mod.rs b/meilisearch/src/search/mod.rs
index 13cfb9334..4d5d8d890 100644
--- a/meilisearch/src/search/mod.rs
+++ b/meilisearch/src/search/mod.rs
@@ -455,9 +455,8 @@ impl SearchQueryWithIndex {
         }
     }
 
-    pub fn has_facets(&self) -> bool {
-        let Some(facets) = &self.facets else { return false };
-        !facets.is_empty()
+    pub fn has_facets(&self) -> Option<&[String]> {
+        self.facets.as_deref().filter(|v| !v.is_empty())
     }
 
     pub fn into_index_query_federation(self) -> (IndexUid, SearchQuery, Option<FederationOptions>) {