Fix number of deleted tasks details after duplicate task deletion

index-scheduler/src/batch.rs

@@ -819,7 +819,7 @@ impl IndexScheduler {
 
     /// Delete each given task from all the databases (if it is deleteable).
     ///
-    /// Return the number of tasks that were actually deleted
+    /// Return the number of tasks that were actually deleted.
     fn delete_matched_tasks(
         &self,
         wtxn: &mut RwTxn,
@@ -830,11 +830,9 @@ impl IndexScheduler {
 
         let processing_tasks = &self.processing_tasks.read().unwrap().1;
 
-        // TODO: Lo: Take the intersection of `matched_tasks` and `all_tasks` first,
-        // so that we end up with the correct count for `deleted_tasks` (the value returned
-        // by this function). Related snapshot test:
-        // `task_deletion_delete_same_task_twice/task_deletion_processed.snap`
-        let mut to_delete_tasks = matched_tasks - processing_tasks;
+        let all_task_ids = self.all_task_ids(&wtxn)?;
+        let mut to_delete_tasks = all_task_ids & matched_tasks;
+        to_delete_tasks -= processing_tasks;
         to_delete_tasks -= enqueued_tasks;
 
         // 2. We now have a list of tasks to delete, delete them
@@ -844,6 +842,8 @@ impl IndexScheduler {
         let mut affected_kinds = HashSet::new();
 
         for task_id in to_delete_tasks.iter() {
+            // This should never fail, but there is no harm done if it does. The function
+            // will still be 99% correct (the number of deleted tasks will be slightly incorrect).
             if let Some(task) = self.get_task(wtxn, task_id)? {
                 if let Some(task_indexes) = task.indexes() {
                     affected_indexes.extend(task_indexes.into_iter().map(|x| x.to_owned()));

index-scheduler/src/lib.rs

@@ -262,18 +262,7 @@ impl IndexScheduler {
         let rtxn = self.env.read_txn()?;
 
         // This is the list of all the tasks.
-        let mut tasks = {
-            let mut all_tasks = RoaringBitmap::new();
-            for status in [
-                Status::Enqueued,
-                Status::Processing,
-                Status::Succeeded,
-                Status::Failed,
-            ] {
-                all_tasks |= self.get_status(&rtxn, status)?;
-            }
-            all_tasks
-        };
+        let mut tasks = self.all_task_ids(&rtxn)?;
 
         if let Some(uids) = &query.uid {
             tasks &= RoaringBitmap::from_iter(uids);
@@ -827,8 +816,6 @@ mod tests {
         for _ in 0..2 {
             handle.wait_till(Breakpoint::AfterProcessing);
         }
-        // The three deletion tasks are marked as succeeded, and all their details say that one
-        // task has been deleted. Is this the correct behaviour? Probably not!
         snapshot!(snapshot_index_scheduler(&index_scheduler), name: "task_deletion_processed");
     }
 

index-scheduler/src/snapshots/lib.rs/task_deletion_delete_same_task_twice/task_deletion_processed.snap

@@ -8,7 +8,7 @@ source: index-scheduler/src/lib.rs
 ### All Tasks:
 1 {uid: 1, status: enqueued, details: { received_documents: 1, indexed_documents: 0 }, kind: DocumentImport { index_uid: "doggo", primary_key: Some("bone"), method: ReplaceDocuments, content_file: 00000000-0000-0000-0000-000000000001, documents_count: 1, allow_index_creation: true }}
 2 {uid: 2, status: succeeded, details: { matched_tasks: 1, deleted_tasks: Some(1), original_query: "test_query" }, kind: TaskDeletion { query: "test_query", tasks: RoaringBitmap<[0]> }}
-3 {uid: 3, status: succeeded, details: { matched_tasks: 1, deleted_tasks: Some(1), original_query: "test_query" }, kind: TaskDeletion { query: "test_query", tasks: RoaringBitmap<[0]> }}
+3 {uid: 3, status: succeeded, details: { matched_tasks: 1, deleted_tasks: Some(0), original_query: "test_query" }, kind: TaskDeletion { query: "test_query", tasks: RoaringBitmap<[0]> }}
 ----------------------------------------------------------------------
 ### Status:
 enqueued [1,]

index-scheduler/src/utils.rs

@@ -8,6 +8,18 @@ use crate::{Error, IndexScheduler, Result, Task, TaskId};
 use meilisearch_types::tasks::{Kind, Status};
 
 impl IndexScheduler {
+    pub(crate) fn all_task_ids(&self, rtxn: &RoTxn) -> Result<RoaringBitmap> {
+        let mut all_tasks = RoaringBitmap::new();
+        for status in [
+            Status::Enqueued,
+            Status::Processing,
+            Status::Succeeded,
+            Status::Failed,
+        ] {
+            all_tasks |= self.get_status(&rtxn, status)?;
+        }
+        Ok(all_tasks)
+    }
     pub(crate) fn last_task_id(&self, rtxn: &RoTxn) -> Result<Option<TaskId>> {
         Ok(self
             .all_tasks