From b6a0abea9f907e17f75404b4a470d2feecb585f9 Mon Sep 17 00:00:00 2001
From: Irevoire <tamo@meilisearch.com>
Date: Thu, 20 Oct 2022 13:18:25 +0200
Subject: [PATCH] =?UTF-8?q?fix=20the=20index=20deletion=20when=20the=20ind?=
 =?UTF-8?q?ex=20doesn=E2=80=99t=20exists=20but=20would=20be=20created=20by?=
 =?UTF-8?q?=20one=20of=20the=20autobatched=20tasks?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 index-scheduler/src/batch.rs | 17 ++++++++++++----
 index-scheduler/src/lib.rs   | 39 ++++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/index-scheduler/src/batch.rs b/index-scheduler/src/batch.rs
index f6b4f1ed1..c54be3338 100644
--- a/index-scheduler/src/batch.rs
+++ b/index-scheduler/src/batch.rs
@@ -74,6 +74,7 @@ pub(crate) enum Batch {
     IndexDeletion {
         index_uid: String,
         tasks: Vec<Task>,
+        index_has_been_created: bool,
     },
     IndexSwap {
         task: Task,
@@ -444,6 +445,7 @@ impl IndexScheduler {
             }
             BatchKind::IndexDeletion { ids } => Ok(Some(Batch::IndexDeletion {
                 index_uid,
+                index_has_been_created: must_create_index,
                 tasks: self.get_existing_tasks(rtxn, ids)?,
             })),
             BatchKind::IndexSwap { id } => {
@@ -796,18 +798,25 @@ impl IndexScheduler {
             }
             Batch::IndexDeletion {
                 index_uid,
+                index_has_been_created,
                 mut tasks,
             } => {
                 let wtxn = self.env.write_txn()?;
 
-                let number_of_documents = {
+                // it's possible that the index doesn't exist
+                let number_of_documents = || -> Result<u64> {
                     let index = self.index_mapper.index(&wtxn, &index_uid)?;
                     let index_rtxn = index.read_txn()?;
-                    index.number_of_documents(&index_rtxn)?
-                };
+                    Ok(index.number_of_documents(&index_rtxn)?)
+                }()
+                .unwrap_or_default();
 
                 // The write transaction is directly owned and commited inside.
-                self.index_mapper.delete_index(wtxn, &index_uid)?;
+                match self.index_mapper.delete_index(wtxn, &index_uid) {
+                    Ok(()) => (),
+                    Err(Error::IndexNotFound(_)) if index_has_been_created => (),
+                    Err(e) => return Err(e),
+                }
 
                 // We set all the tasks details to the default value.
                 for task in &mut tasks {
diff --git a/index-scheduler/src/lib.rs b/index-scheduler/src/lib.rs
index 234ff7451..5faedcb5d 100644
--- a/index-scheduler/src/lib.rs
+++ b/index-scheduler/src/lib.rs
@@ -1327,6 +1327,45 @@ mod tests {
         snapshot!(snapshot_index_scheduler(&index_scheduler), name: "second_swap_processed");
     }
 
+    #[test]
+    fn document_addition_and_index_deletion_on_unexisting_index() {
+        let (index_scheduler, handle) = IndexScheduler::test(true);
+
+        let content = r#"
+        {
+            "id": 1,
+            "doggo": "bob"
+        }"#;
+
+        let (uuid, mut file) = index_scheduler.create_update_file_with_uuid(0).unwrap();
+        let documents_count =
+            meilisearch_types::document_formats::read_json(content.as_bytes(), file.as_file_mut())
+                .unwrap() as u64;
+        file.persist().unwrap();
+        index_scheduler
+            .register(KindWithContent::DocumentImport {
+                index_uid: S("doggos"),
+                primary_key: Some(S("id")),
+                method: ReplaceDocuments,
+                content_file: uuid,
+                documents_count,
+                allow_index_creation: true,
+            })
+            .unwrap();
+        index_scheduler
+            .register(KindWithContent::IndexDeletion {
+                index_uid: S("doggos"),
+            })
+            .unwrap();
+
+        snapshot!(snapshot_index_scheduler(&index_scheduler));
+
+        handle.wait_till(Breakpoint::Start); // before anything happens.
+        handle.wait_till(Breakpoint::Start); // after the execution of the two tasks in a single batch.
+
+        snapshot!(snapshot_index_scheduler(&index_scheduler));
+    }
+
     #[macro_export]
     macro_rules! debug_snapshot {
         ($value:expr, @$snapshot:literal) => {{