Fix erase setting option

meilisearch-http/src/helpers/meilisearch.rs

@@ -1,4 +1,4 @@
-use crate::routes::setting::{RankingOrdering, SettingBody};
+use crate::routes::setting::{RankingOrdering, Setting};
 use indexmap::IndexMap;
 use log::{error, warn};
 use meilisearch_core::criterion::*;
@@ -299,7 +299,7 @@ impl<'a> SearchBuilder<'a> {
     ) -> Result<Option<Criteria<'a>>, Error> {
         let current_settings = match self.index.main.customs(reader).unwrap() {
             Some(bytes) => bincode::deserialize(bytes).unwrap(),
-            None => SettingBody::default(),
+            None => Setting::default(),
         };
 
         let ranking_rules = &current_settings.ranking_rules;

meilisearch-http/src/routes/setting.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
 use http::StatusCode;
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Serialize, Deserializer};
 use tide::response::IntoResponse;
 use tide::{Context, Response};
 
@@ -11,9 +11,9 @@ use crate::models::token::ACL::*;
 use crate::routes::document::IndexUpdateResponse;
 use crate::Data;
 
-#[derive(Default, Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Default, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase", deny_unknown_fields)]
-pub struct SettingBody {
+pub struct Setting {
     pub ranking_order: Option<RankingOrder>,
     pub distinct_field: Option<DistinctField>,
     pub ranking_rules: Option<RankingRules>,
@@ -39,12 +39,31 @@ pub async fn get(ctx: Context<Data>) -> SResult<Response> {
 
     let settings = match index.main.customs(&reader).unwrap() {
         Some(bytes) => bincode::deserialize(bytes).unwrap(),
-        None => SettingBody::default(),
+        None => Setting::default(),
     };
 
     Ok(tide::response::json(settings))
 }
 
+#[derive(Deserialize)]
+#[serde(rename_all = "camelCase", deny_unknown_fields)]
+pub struct SettingBody {
+    #[serde(default, deserialize_with = "deserialize_some")]
+    pub ranking_order: Option<Option<RankingOrder>>,
+    #[serde(default, deserialize_with = "deserialize_some")]
+    pub distinct_field: Option<Option<DistinctField>>,
+    #[serde(default, deserialize_with = "deserialize_some")]
+    pub ranking_rules: Option<Option<RankingRules>>,
+}
+
+// Any value that is present is considered Some value, including null.
+fn deserialize_some<'de, T, D>(deserializer: D) -> Result<Option<T>, D::Error>
+    where T: Deserialize<'de>,
+          D: Deserializer<'de>
+{
+    Deserialize::deserialize(deserializer).map(Some)
+}
+
 pub async fn update(mut ctx: Context<Data>) -> SResult<Response> {
     ctx.is_allowed(SettingsWrite)?;
 
@@ -58,19 +77,19 @@ pub async fn update(mut ctx: Context<Data>) -> SResult<Response> {
 
     let mut current_settings = match index.main.customs(&reader).unwrap() {
         Some(bytes) => bincode::deserialize(bytes).unwrap(),
-        None => SettingBody::default(),
+        None => Setting::default(),
     };
 
     if let Some(ranking_order) = settings.ranking_order {
-        current_settings.ranking_order = Some(ranking_order);
+        current_settings.ranking_order = ranking_order;
     }
 
     if let Some(distinct_field) = settings.distinct_field {
-        current_settings.distinct_field = Some(distinct_field);
+        current_settings.distinct_field = distinct_field;
     }
 
     if let Some(ranking_rules) = settings.ranking_rules {
-        current_settings.ranking_rules = Some(ranking_rules);
+        current_settings.ranking_rules = ranking_rules;
     }
 
     let bytes = bincode::serialize(&current_settings).unwrap();