apply all style review comments

milli/src/error.rs

@@ -32,6 +32,8 @@ pub enum InternalError {
     DatabaseClosing,
     #[error("Missing {} in the {db_name} database.", key.unwrap_or("key"))]
     DatabaseMissingEntry { db_name: &'static str, key: Option<&'static str> },
+    #[error("Missing {key} in the fieldids weights mapping.")]
+    FieldidsWeightsMapMissingEntry { key: FieldId },
     #[error(transparent)]
     FieldIdMapMissingEntry(#[from] FieldIdMapMissingEntry),
     #[error("Missing {key} in the field id mapping.")]

milli/src/fieldids_weights_map.rs

@@ -1,3 +1,5 @@
+//! The fieldids weights map is in charge of storing linking the searchable fields with their weights.
+
 use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
@@ -10,22 +12,29 @@ pub struct FieldidsWeightsMap {
 }
 
 impl FieldidsWeightsMap {
+    /// Insert a field id -> weigth into the map.
+    /// If the map did not have this key present, `None` is returned.
+    /// If the map did have this key present, the value is updated, and the old value is returned.
     pub fn insert(&mut self, fid: FieldId, weight: Weight) -> Option<Weight> {
         self.map.insert(fid, weight)
     }
 
+    /// Removes a field id from the map, returning the associated weight previously in the map.
     pub fn remove(&mut self, fid: FieldId) -> Option<Weight> {
         self.map.remove(&fid)
     }
 
+    /// Returns weight corresponding to the key.
     pub fn weight(&self, fid: FieldId) -> Option<Weight> {
         self.map.get(&fid).copied()
     }
 
+    /// Returns highest weight contained in the map if any.
     pub fn max_weight(&self) -> Option<Weight> {
         self.map.values().copied().max()
     }
 
+    /// Return an iterator visiting all field ids in arbitrary order.
     pub fn ids(&self) -> impl Iterator<Item = FieldId> + '_ {
         self.map.keys().copied()
     }

milli/src/index.rs

@@ -26,9 +26,9 @@ use crate::proximity::ProximityPrecision;
 use crate::vector::EmbeddingConfig;
 use crate::{
     default_criteria, CboRoaringBitmapCodec, Criterion, DocumentId, ExternalDocumentsIds,
-    FacetDistribution, FieldDistribution, FieldId, FieldIdWordCountCodec, FieldidsWeightsMap,
-    GeoPoint, ObkvCodec, Result, RoaringBitmapCodec, RoaringBitmapLenCodec, Search, U8StrStrCodec,
-    Weight, BEU16, BEU32, BEU64,
+    FacetDistribution, FieldDistribution, FieldId, FieldIdMapMissingEntry, FieldIdWordCountCodec,
+    FieldidsWeightsMap, GeoPoint, ObkvCodec, Result, RoaringBitmapCodec, RoaringBitmapLenCodec,
+    Search, U8StrStrCodec, Weight, BEU16, BEU32, BEU64,
 };
 
 pub const DEFAULT_MIN_WORD_LEN_ONE_TYPO: u8 = 5;
@@ -446,22 +446,25 @@ impl Index {
     pub fn searchable_fields_and_weights<'a>(
         &self,
         rtxn: &'a RoTxn,
-    ) -> heed::Result<Vec<(Cow<'a, str>, FieldId, Weight)>> {
+    ) -> Result<Vec<(Cow<'a, str>, FieldId, Weight)>> {
         let fid_map = self.fields_ids_map(rtxn)?;
         let weight_map = self.fieldids_weights_map(rtxn)?;
         let searchable = self.searchable_fields(rtxn)?;
 
-        Ok(searchable
+        searchable
             .into_iter()
-            .map(|field| {
-                // the searchable attributes are a subset of the field id map
-                let fid = fid_map.id(&field).unwrap();
-                // all the searchable fields have a weight
-                let weight = weight_map.weight(fid).unwrap();
+            .map(|field| -> Result<_> {
+                let fid = fid_map.id(&field).ok_or_else(|| FieldIdMapMissingEntry::FieldName {
+                    field_name: field.to_string(),
+                    process: "searchable_fields_and_weights",
+                })?;
+                let weight = weight_map
+                    .weight(fid)
+                    .ok_or(InternalError::FieldidsWeightsMapMissingEntry { key: fid })?;
 
-                (field, fid, weight)
+                Ok((field, fid, weight))
             })
-            .collect())
+            .collect()
     }
 
     /* geo rtree */

milli/src/search/new/ranking_rule_graph/fid/mod.rs

@@ -7,7 +7,7 @@ use crate::search::new::interner::{DedupInterner, Interned};
 use crate::search::new::query_term::LocatedQueryTermSubset;
 use crate::search::new::resolve_query_graph::compute_query_term_subset_docids_within_field_id;
 use crate::search::new::SearchContext;
-use crate::{FieldId, Result};
+use crate::{FieldId, InternalError, Result};
 
 #[derive(Clone, PartialEq, Eq, Hash)]
 pub struct FidCondition {
@@ -29,10 +29,9 @@ impl RankingRuleGraphTrait for FidGraph {
 
         let docids = if let Some(fid) = condition.fid {
             // maybe compute_query_term_subset_docids_within_field_id should accept a universe as argument
-            let mut docids =
+            let docids =
                 compute_query_term_subset_docids_within_field_id(ctx, &term.term_subset, fid)?;
-            docids &= universe;
-            docids
+            docids & universe
         } else {
             RoaringBitmap::new()
         };
@@ -75,7 +74,9 @@ impl RankingRuleGraphTrait for FidGraph {
 
         let mut edges = vec![];
         for fid in all_fields.iter().copied() {
-            let weight = weights_map.weight(fid).unwrap();
+            let weight = weights_map
+                .weight(fid)
+                .ok_or(InternalError::FieldidsWeightsMapMissingEntry { key: fid })?;
             edges.push((
                 weight as u32 * term.term_ids.len() as u32,
                 conditions_interner.insert(FidCondition { term: term.clone(), fid: Some(fid) }),

milli/src/update/settings.rs

@@ -475,33 +475,25 @@ impl<'a, 't, 'i> Settings<'a, 't, 'i> {
                     return Ok(false);
                 }
 
-                // every time the searchable attributes are updated, we need to update the
-                // ids for any settings that uses the facets. (distinct_fields, filterable_fields).
-                let old_fields_ids_map = self.index.fields_ids_map(self.wtxn)?;
-
                 // Since we're updating the settings we can only add new fields at the end of the field id map
-                let mut new_fields_ids_map = old_fields_ids_map.clone();
-                let names = fields
-                    .iter()
-                    // fields are deduplicated, only the first occurrence is taken into account
-                    .unique()
-                    .map(String::as_str)
-                    .collect::<Vec<_>>();
+                let mut fields_ids_map = self.index.fields_ids_map(self.wtxn)?;
+                // fields are deduplicated, only the first occurrence is taken into account
+                let names = fields.iter().unique().map(String::as_str).collect::<Vec<_>>();
 
                 // Add all the searchable attributes to the field map, and then add the
                 // remaining fields from the old field map to the new one
                 for name in names.iter() {
                     // The fields ids map won't change the field id of already present elements thus only the
                     // new fields will be inserted.
-                    new_fields_ids_map.insert(name).ok_or(UserError::AttributeLimitReached)?;
+                    fields_ids_map.insert(name).ok_or(UserError::AttributeLimitReached)?;
                 }
 
                 self.index.put_all_searchable_fields_from_fields_ids_map(
                     self.wtxn,
                     Some(&names),
-                    &new_fields_ids_map,
+                    &fields_ids_map,
                 )?;
-                self.index.put_fields_ids_map(self.wtxn, &new_fields_ids_map)?;
+                self.index.put_fields_ids_map(self.wtxn, &fields_ids_map)?;
                 Ok(true)
             }
             Setting::Reset => Ok(self.index.delete_all_searchable_fields(self.wtxn)?),