From e89973f1bf01c8a687275116205abf9d869df104 Mon Sep 17 00:00:00 2001
From: Kerollmops <clement@meilisearch.com>
Date: Wed, 18 Jan 2023 15:25:27 +0100
Subject: [PATCH] Do not delete all tasks when no canceled-by matches

---
 index-scheduler/src/lib.rs | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/index-scheduler/src/lib.rs b/index-scheduler/src/lib.rs
index 0b9e856d2..4374a0612 100644
--- a/index-scheduler/src/lib.rs
+++ b/index-scheduler/src/lib.rs
@@ -502,13 +502,22 @@ impl IndexScheduler {
         }
 
         if let Some(canceled_by) = &query.canceled_by {
+            let mut all_canceled_tasks = RoaringBitmap::new();
             for cancel_task_uid in canceled_by {
                 if let Some(canceled_by_uid) =
                     self.canceled_by.get(rtxn, &BEU32::new(*cancel_task_uid))?
                 {
-                    tasks &= canceled_by_uid;
+                    all_canceled_tasks |= canceled_by_uid;
                 }
             }
+
+            // if the canceled_by has been specified but no task
+            // matches then we prefer matching zero than all tasks.
+            if all_canceled_tasks.is_empty() {
+                return Ok(RoaringBitmap::new());
+            } else {
+                tasks &= all_canceled_tasks;
+            }
         }
 
         if let Some(kind) = &query.types {