Gate behind multimodal experimental feature

crates/filter-parser/src/lib.rs

@@ -189,6 +189,25 @@ impl<'a> FilterCondition<'a> {
         }
     }
 
+    pub fn use_vector_filter(&self) -> Option<&Token> {
+        match self {
+            FilterCondition::Condition { fid, op: _ } => {
+                if fid.value().starts_with("_vectors.") || fid.value() == "_vectors" {
+                    Some(fid)
+                } else {
+                    None
+                }
+            }
+            FilterCondition::Not(this) => this.use_vector_filter(),
+            FilterCondition::Or(seq) | FilterCondition::And(seq) => {
+                seq.iter().find_map(|filter| filter.use_vector_filter())
+            }
+            FilterCondition::GeoLowerThan { .. }
+            | FilterCondition::GeoBoundingBox { .. }
+            | FilterCondition::In { .. } => None,
+        }
+    }
+
     pub fn fids(&self, depth: usize) -> Box<dyn Iterator<Item = &Token> + '_> {
         if depth == 0 {
             return Box::new(std::iter::empty());

crates/meilisearch/src/search/mod.rs

@@ -2077,7 +2077,7 @@ pub(crate) fn parse_filter(
     })?;
 
     if let Some(ref filter) = filter {
-        // If the contains operator is used while the contains filter features is not enabled, errors out
+        // If the contains operator is used while the contains filter feature is not enabled, errors out
         if let Some((token, error)) =
             filter.use_contains_operator().zip(features.check_contains_filter().err())
         {
@@ -2088,6 +2088,18 @@ pub(crate) fn parse_filter(
         }
     }
 
+    if let Some(ref filter) = filter {
+        // If a vector filter is used while the multi modal feature is not enabled, errors out
+        if let Some((token, error)) =
+            filter.use_vector_filter().zip(features.check_multimodal("using a vector filter").err())
+        {
+            return Err(ResponseError::from_msg(
+                token.as_external_error(error).to_string(),
+                Code::FeatureNotEnabled,
+            ));
+        }
+    }
+
     Ok(filter)
 }
 

crates/meilisearch/tests/search/filters.rs

@@ -1068,6 +1068,26 @@ async fn vector_filter_document_template() {
     "#);
 }
 
+#[actix_rt::test]
+async fn vector_filter_feature_gate() {
+    let index = shared_index_with_documents().await;
+
+    let (value, _code) = index
+        .search_post(json!({
+            "filter": "_vectors EXISTS",
+            "attributesToRetrieve": ["name"]
+        }))
+        .await;
+    snapshot!(value, @r#"
+    {
+      "message": "using a vector filter requires enabling the `multimodal` experimental feature. See https://github.com/orgs/meilisearch/discussions/846\n1:9 _vectors EXISTS",
+      "code": "feature_not_enabled",
+      "type": "invalid_request",
+      "link": "https://docs.meilisearch.com/errors#feature_not_enabled"
+    }
+    "#);
+}
+
 #[actix_rt::test]
 async fn vector_filter_negation() {
     let index = crate::vector::shared_index_for_fragments().await;

crates/milli/src/search/facet/filter.rs

@@ -228,6 +228,10 @@ impl<'a> Filter<'a> {
     pub fn use_contains_operator(&self) -> Option<&Token> {
         self.condition.use_contains_operator()
     }
+
+    pub fn use_vector_filter(&self) -> Option<&Token> {
+        self.condition.use_vector_filter()
+    }
 }
 
 impl<'a> Filter<'a> {