Support deleting documents with functions

index-scheduler/src/batch.rs

@@ -1420,7 +1420,7 @@ impl IndexScheduler {
                     } else {
                         unreachable!()
                     };
-                let edited_documents = edit_documents_by_function(
+                let result_count = edit_documents_by_function(
                     index_wtxn,
                     filter,
                     context.clone(),
@@ -1442,13 +1442,14 @@ impl IndexScheduler {
                     unreachable!();
                 };
 
-                match edited_documents {
+                match result_count {
-                    Ok(edited_documents) => {
+                    Ok((deleted_documents, edited_documents)) => {
                         task.status = Status::Succeeded;
                         task.details = Some(Details::DocumentEdition {
                             original_filter,
                             context,
                             function,
+                            deleted_documents: Some(deleted_documents),
                             edited_documents: Some(edited_documents),
                         });
                     }
@@ -1458,6 +1459,7 @@ impl IndexScheduler {
                             original_filter,
                             context,
                             function,
+                            deleted_documents: Some(0),
                             edited_documents: Some(0),
                         });
                         task.error = Some(e.into());
@@ -1763,7 +1765,7 @@ fn edit_documents_by_function<'a>(
     indexer_config: &IndexerConfig,
     must_stop_processing: MustStopProcessing,
     index: &'a Index,
-) -> Result<u64> {
+) -> Result<(u64, u64)> {
     let candidates = match filter.as_ref().map(Filter::from_json) {
         Some(Ok(Some(filter))) => filter.evaluate(wtxn, index).map_err(|err| match err {
             milli::Error::UserError(milli::UserError::InvalidFilter(_)) => {

index-scheduler/src/insta_snapshot.rs

@@ -178,12 +178,15 @@ fn snapshot_details(d: &Details) -> String {
             format!("{{ received_documents: {received_documents}, indexed_documents: {indexed_documents:?} }}")
         }
         Details::DocumentEdition {
+            deleted_documents,
             edited_documents,
             original_filter,
             context,
             function,
         } => {
-            format!("{{ edited_documents: {edited_documents:?}, context: {context:?}, function: {function:?}, original_filter: {original_filter:?} }}")
+            format!(
+                "{{ deleted_documents: {deleted_documents:?}, edited_documents: {edited_documents:?}, context: {context:?}, function: {function:?}, original_filter: {original_filter:?} }}"
+            )
         }
         Details::SettingsUpdate { settings } => {
             format!("{{ settings: {settings:?} }}")

meilisearch-types/src/task_view.rs

@@ -93,15 +93,20 @@ impl From<Details> for DetailsView {
                     ..DetailsView::default()
                 }
             }
-            Details::DocumentEdition { edited_documents, original_filter, context, function } => {
+            Details::DocumentEdition {
-                DetailsView {
+                deleted_documents,
+                edited_documents,
+                original_filter,
+                context,
+                function,
+            } => DetailsView {
+                deleted_documents: Some(deleted_documents),
                 edited_documents: Some(edited_documents),
                 original_filter: Some(original_filter),
                 context: Some(context),
                 function: Some(function),
                 ..DetailsView::default()
-                }
+            },
-            }
             Details::SettingsUpdate { mut settings } => {
                 settings.hide_secrets();
                 DetailsView { settings: Some(settings), ..DetailsView::default() }

meilisearch-types/src/tasks.rs

@@ -215,6 +215,7 @@ impl KindWithContent {
             }
             KindWithContent::DocumentEdition { index_uid: _, filter_expr, context, function } => {
                 Some(Details::DocumentEdition {
+                    deleted_documents: None,
                     edited_documents: None,
                     original_filter: filter_expr.as_ref().map(|v| v.to_string()),
                     context: context.clone(),
@@ -271,6 +272,7 @@ impl KindWithContent {
             }
             KindWithContent::DocumentEdition { index_uid: _, filter_expr, context, function } => {
                 Some(Details::DocumentEdition {
+                    deleted_documents: Some(0),
                     edited_documents: Some(0),
                     original_filter: filter_expr.as_ref().map(|v| v.to_string()),
                     context: context.clone(),
@@ -533,6 +535,7 @@ pub enum Details {
         indexed_documents: Option<u64>,
     },
     DocumentEdition {
+        deleted_documents: Option<u64>,
         edited_documents: Option<u64>,
         original_filter: Option<String>,
         context: Option<Object>,

milli/src/update/index_documents/mod.rs

@@ -179,10 +179,10 @@ where
         documents: &RoaringBitmap,
         context: Option<Object>,
         code: &str,
-    ) -> Result<(Self, StdResult<u64, UserError>)> {
+    ) -> Result<(Self, StdResult<(u64, u64), UserError>)> {
         // Early return when there is no document to add
         if documents.is_empty() {
-            return Ok((self, Ok(0)));
+            return Ok((self, Ok((0, 0))));
         }
 
         /// Transform every field of a raw obkv store into a Rhai Map.
@@ -228,6 +228,7 @@ where
         let primary_key = self.index.primary_key(self.wtxn)?.unwrap();
         let primary_key_id = fields_ids_map.id(primary_key).unwrap();
         let mut documents_batch_builder = tempfile::tempfile().map(DocumentsBatchBuilder::new)?;
+        let mut documents_to_remove = RoaringBitmap::new();
 
         let context: Dynamic = match context {
             Some(context) => serde_json::from_value(context.into()).unwrap(),
@@ -252,8 +253,19 @@ where
             scope.push_constant_dynamic("context", context.clone());
             scope.push("doc", document);
             let _ = engine.eval_ast_with_scope::<Dynamic>(&mut scope, &ast).unwrap();
-            let new_document = scope.remove("doc").unwrap();
+            let new_document = match scope.remove::<Dynamic>("doc") {
-            let new_document = rhaimap_to_object(new_document);
+                // If the "doc" variable has been removed from the scope
+                // or set to (), we effectively delete the document.
+                Some(doc) if doc.is_unit() => {
+                    documents_to_remove.push(docid);
+                    continue;
+                }
+                None => unreachable!(),
+                Some(document) => match document.try_cast() {
+                    Some(document) => rhaimap_to_object(document),
+                    None => panic!("Why is \"doc\" no longer a Map?"),
+                },
+            };
 
             if document_object != new_document {
                 assert_eq!(
@@ -268,7 +280,10 @@ where
         let file = documents_batch_builder.into_inner()?;
         let reader = DocumentsBatchReader::from_reader(file)?;
 
-        self.add_documents(reader)
+        let (this, removed) = self.remove_documents_from_db_no_batch(&documents_to_remove)?;
+        let (this, result) = this.add_documents(reader)?;
+
+        Ok((this, result.map(|added| (removed, added))))
     }
 
     pub fn with_embedders(mut self, embedders: EmbeddingConfigs) -> Self {