Fix PR creation task for directives to be atomic

1 files changed, 19 insertions, 1 deletions

diff --git a/makima/src/db/repository.rs b/makima/src/db/repository.rs
index 127f4cd..a79818f 100644
--- a/makima/src/db/repository.rs
+++ b/makima/src/db/repository.rs
@@ -5229,7 +5229,25 @@ pub async fn get_completion_tasks_to_check(
     .await
 }
 
-/// Assign a completion task to a directive.
+/// Atomically claim a directive for completion by setting a placeholder completion_task_id.
+/// Returns true if the claim was successful (no other task already claimed it).
+pub async fn claim_directive_for_completion(
+    pool: &PgPool,
+    directive_id: Uuid,
+    task_id: Uuid,
+) -> Result<bool, sqlx::Error> {
+    let result = sqlx::query(
+        r#"UPDATE directives SET completion_task_id = $2, updated_at = NOW()
+           WHERE id = $1 AND completion_task_id IS NULL"#,
+    )
+    .bind(directive_id)
+    .bind(task_id)
+    .execute(pool)
+    .await?;
+    Ok(result.rows_affected() > 0)
+}
+
+/// Assign a completion task to a directive (unconditional update).
 pub async fn assign_completion_task(
     pool: &PgPool,
     directive_id: Uuid,