From 7df0417bcdcbc62f8b12b631076cb824bc917f87 Mon Sep 17 00:00:00 2001
From: Serban Iorga <serban@parity.io>
Date: Thu, 2 Nov 2023 16:02:41 +0200
Subject: [PATCH] XCM MultiAssets: sort after reanchoring (#2129)
Fixes https://github.com/paritytech/polkadot-sdk/issues/2123
---
polkadot/xcm/src/v3/multiasset.rs | 42 ++++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)
diff --git a/polkadot/xcm/src/v3/multiasset.rs b/polkadot/xcm/src/v3/multiasset.rs
index 9d86fb8deff..454120a1a7b 100644
--- a/polkadot/xcm/src/v3/multiasset.rs
+++ b/polkadot/xcm/src/v3/multiasset.rs
@@ -689,12 +689,16 @@ impl MultiAssets {
/// Mutate the location of the asset identifier if concrete, giving it the same location
/// relative to a `target` context. The local context is provided as `context`.
+ ///
+ /// This will also re-sort the inner assets to preserve ordering guarantees.
pub fn reanchor(
&mut self,
target: &MultiLocation,
context: InteriorMultiLocation,
) -> Result<(), ()> {
- self.0.iter_mut().try_for_each(|i| i.reanchor(target, context))
+ self.0.iter_mut().try_for_each(|i| i.reanchor(target, context))?;
+ self.0.sort();
+ Ok(())
}
/// Return a reference to an item at a specific index or `None` if it doesn't exist.
@@ -985,6 +989,42 @@ mod tests {
assert!(r.is_err());
}
+ #[test]
+ fn reanchor_preserves_sorting() {
+ use super::*;
+ use alloc::vec;
+
+ let reanchor_context = X1(Parachain(2000));
+ let dest = MultiLocation::new(1, Here);
+
+ let asset_1: MultiAsset =
+ (MultiLocation::new(0, X2(PalletInstance(50), GeneralIndex(1))), 10).into();
+ let mut asset_1_reanchored = asset_1.clone();
+ assert!(asset_1_reanchored.reanchor(&dest, reanchor_context).is_ok());
+ assert_eq!(
+ asset_1_reanchored,
+ (MultiLocation::new(0, X3(Parachain(2000), PalletInstance(50), GeneralIndex(1))), 10)
+ .into()
+ );
+
+ let asset_2: MultiAsset = (MultiLocation::new(1, Here), 10).into();
+ let mut asset_2_reanchored = asset_2.clone();
+ assert!(asset_2_reanchored.reanchor(&dest, reanchor_context).is_ok());
+ assert_eq!(asset_2_reanchored, (MultiLocation::new(0, Here), 10).into());
+
+ let asset_3: MultiAsset = (MultiLocation::new(1, X1(Parachain(1000))), 10).into();
+ let mut asset_3_reanchored = asset_3.clone();
+ assert!(asset_3_reanchored.reanchor(&dest, reanchor_context).is_ok());
+ assert_eq!(asset_3_reanchored, (MultiLocation::new(0, X1(Parachain(1000))), 10).into());
+
+ let mut assets: MultiAssets =
+ vec![asset_1.clone(), asset_2.clone(), asset_3.clone()].into();
+ assert_eq!(assets.clone(), vec![asset_1.clone(), asset_2.clone(), asset_3.clone()].into());
+
+ assert!(assets.reanchor(&dest, reanchor_context).is_ok());
+ assert_eq!(assets, vec![asset_2_reanchored, asset_3_reanchored, asset_1_reanchored].into());
+ }
+
#[test]
fn decoding_respects_limit() {
use super::*;
--
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