From 1f5d80127162db8ab6f7b4004d32dc1b09a57898 Mon Sep 17 00:00:00 2001
From: ManyTheFish <many@meilisearch.com>
Date: Thu, 7 Nov 2024 17:22:30 +0100
Subject: [PATCH] Fix crashes in facet search indexing

---
 .../src/update/new/extract/faceted/mod.rs     |  1 -
 .../src/update/new/facet_search_builder.rs    | 23 +++++--------------
 crates/milli/src/update/new/indexer/mod.rs    |  6 ++---
 3 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/crates/milli/src/update/new/extract/faceted/mod.rs b/crates/milli/src/update/new/extract/faceted/mod.rs
index bfe8efd03..0c012d739 100644
--- a/crates/milli/src/update/new/extract/faceted/mod.rs
+++ b/crates/milli/src/update/new/extract/faceted/mod.rs
@@ -28,7 +28,6 @@ impl From<u8> for FacetKind {
 
 impl FacetKind {
     pub fn extract_from_key(key: &[u8]) -> (FacetKind, &[u8]) {
-        debug_assert!(key.len() > 3);
         (FacetKind::from(key[0]), &key[1..])
     }
 }
diff --git a/crates/milli/src/update/new/facet_search_builder.rs b/crates/milli/src/update/new/facet_search_builder.rs
index 839120540..7eaec95a5 100644
--- a/crates/milli/src/update/new/facet_search_builder.rs
+++ b/crates/milli/src/update/new/facet_search_builder.rs
@@ -54,23 +54,12 @@ impl<'indexer> FacetSearchBuilder<'indexer> {
         }
     }
 
-    fn extract_key_data<'k>(&self, key: &'k [u8]) -> Result<Option<FacetGroupKey<&'k str>>> {
-        match FacetKind::from(key[0]) {
-            // Only strings are searchable
-            FacetKind::String => Ok(Some(
-                FacetGroupKeyCodec::<StrRefCodec>::bytes_decode(&key[1..])
-                    .map_err(heed::Error::Encoding)?,
-            )),
-            _ => Ok(None),
-        }
-    }
-
-    pub fn register_from_key(&mut self, deladd: DelAdd, facet_key: &[u8]) -> Result<()> {
-        let Some(FacetGroupKey { field_id, level: _level, left_bound }) =
-            self.extract_key_data(facet_key)?
-        else {
-            return Ok(());
-        };
+    pub fn register_from_key(
+        &mut self,
+        deladd: DelAdd,
+        facet_key: FacetGroupKey<&str>,
+    ) -> Result<()> {
+        let FacetGroupKey { field_id, level: _level, left_bound } = facet_key;
 
         if deladd == DelAdd::Addition {
             self.registered_facets.entry(field_id).and_modify(|count| *count += 1).or_insert(1);
diff --git a/crates/milli/src/update/new/indexer/mod.rs b/crates/milli/src/update/new/indexer/mod.rs
index 001f59fe4..70ac7f959 100644
--- a/crates/milli/src/update/new/indexer/mod.rs
+++ b/crates/milli/src/update/new/indexer/mod.rs
@@ -681,13 +681,11 @@ fn compute_facet_search_database(
             }
             EitherOrBoth::Left(result) => {
                 let (key, _) = result?;
-                facet_search_builder
-                    .register_from_key(DelAdd::Deletion, key.left_bound.as_ref())?;
+                facet_search_builder.register_from_key(DelAdd::Deletion, key)?;
             }
             EitherOrBoth::Right(result) => {
                 let (key, _) = result?;
-                facet_search_builder
-                    .register_from_key(DelAdd::Addition, key.left_bound.as_ref())?;
+                facet_search_builder.register_from_key(DelAdd::Addition, key)?;
             }
         }
     }