editoast: use only one connection for infra clone

Author: Tristramg

editoast/src/views/infra/mod.rs

@@ -271,17 +271,17 @@ async fn clone(
     db_pool: Data<DbPool>,
     new_name: Query<InfraForm>,
 ) -> Result<Json<i64>> {
-    let db_pool_ref = db_pool.clone();
     let mut futures = Vec::<Pin<Box<dyn Future<Output = _>>>>::new();
 
     let infra = infra.into_inner();
     let name = new_name.name.clone();
-    let cloned_infra = Infra::clone(infra, db_pool_ref.clone(), name).await?;
-
+    let cloned_infra = Infra::clone(infra, db_pool.clone(), name).await?;
+    // When creating a connection for each objet, it will a panic with 'Cannot access shared transaction state' in bb8 database pool
+    // Just one connection fixes it, but partially* defeats the purpose of joining all the requests at the end
+    // * AsyncPgConnection supports pipeling within one connection, but it won’t run parallel
+    let mut conn = db_pool.get().await?;
     for object in ObjectType::iter() {
         let model_table = object.get_table();
-        let db_pool_ref = db_pool.clone();
-        let mut conn = db_pool_ref.get().await?;
         let model = sql_query(format!(
                 "INSERT INTO {model_table}(id, obj_id,data,infra_id) SELECT nextval('{model_table}_id_seq'), obj_id,data,$1 FROM {model_table} WHERE infra_id=$2"
             ))
@@ -300,8 +300,7 @@ async fn clone(
                     "INSERT INTO {layer_table}(id, obj_id,geographic,schematic,infra_id, angle_geo, angle_sch) SELECT nextval('{layer_table}_id_seq'), obj_id,geographic,schematic,$1,angle_geo,angle_sch FROM {layer_table} WHERE infra_id=$2"
                 )
             };
-            let db_pool_ref = db_pool.clone();
-            let mut conn = db_pool_ref.get().await?;
+
             let layer = sql_query(sql)
                 .bind::<BigInt, _>(cloned_infra.id.unwrap())
                 .bind::<BigInt, _>(infra)