[stable2409] Backport #7843 (#7967)

Backport #7843 into `stable2409` from raymondkfcheung.

See the
[documentation](https://github.com/paritytech/polkadot-sdk/blob/master/docs/BACKPORT.md)
on how to use this bot.

<!--
  # To be used by other automation, do not modify:
  original-pr-number: #${pull_number}
-->

---------

Co-authored-by: Raymond Cheung <[email protected]>

Author: paritytech-release-backport-bot[bot]

polkadot/xcm/xcm-builder/src/tests/origins.rs

@@ -139,7 +139,10 @@ fn unpaid_execution_should_work() {
 		Weight::from_parts(50, 50),
 		Weight::zero(),
 	);
-	assert_eq!(r, Outcome::Error { error: XcmError::Barrier });
+	assert_eq!(
+		r,
+		Outcome::Incomplete { used: Weight::from_parts(10, 10), error: XcmError::Barrier }
+	);
 
 	let message = Xcm(vec![UnpaidExecution {
 		weight_limit: Limited(Weight::from_parts(10, 10)),

polkadot/xcm/xcm-builder/src/tests/querying.rs

@@ -130,5 +130,8 @@ fn prepaid_result_of_query_should_get_free_execution() {
 		weight_limit,
 		Weight::zero(),
 	);
-	assert_eq!(r, Outcome::Error { error: XcmError::Barrier });
+	assert_eq!(
+		r,
+		Outcome::Incomplete { used: Weight::from_parts(10, 10), error: XcmError::Barrier }
+	);
 }

polkadot/xcm/xcm-builder/src/tests/version_subscriptions.rs

@@ -37,7 +37,7 @@ fn simple_version_subscriptions_should_work() {
 			weight_limit,
 			Weight::zero(),
 		),
-		Outcome::Error { error: XcmError::Barrier }
+		Outcome::Incomplete { used: Weight::from_parts(20, 20), error: XcmError::Barrier }
 	);
 
 	// this case fails because the additional `SetAppendix` instruction is not allowed in the
@@ -50,7 +50,7 @@ fn simple_version_subscriptions_should_work() {
 			weight_limit,
 			Weight::zero(),
 		),
-		Outcome::Error { error: XcmError::Barrier }
+		Outcome::Incomplete { used: Weight::from_parts(20, 20), error: XcmError::Barrier }
 	);
 
 	let message = Xcm::<TestCall>(vec![SubscribeVersion {
@@ -66,7 +66,10 @@ fn simple_version_subscriptions_should_work() {
 		weight_limit,
 		Weight::zero(),
 	);
-	assert_eq!(r, Outcome::Error { error: XcmError::Barrier });
+	assert_eq!(
+		r,
+		Outcome::Incomplete { used: Weight::from_parts(10, 10), error: XcmError::Barrier }
+	);
 
 	let r = XcmExecutor::<TestConfig>::prepare_and_execute(
 		Parent,
@@ -139,7 +142,10 @@ fn simple_version_unsubscriptions_should_work() {
 		weight_limit,
 		Weight::zero(),
 	);
-	assert_eq!(r, Outcome::Error { error: XcmError::Barrier });
+	assert_eq!(
+		r,
+		Outcome::Incomplete { used: Weight::from_parts(20, 20), error: XcmError::Barrier }
+	);
 
 	let origin = Parachain(1000);
 	let message = Xcm::<TestCall>(vec![UnsubscribeVersion]);
@@ -152,7 +158,10 @@ fn simple_version_unsubscriptions_should_work() {
 		weight_limit,
 		Weight::zero(),
 	);
-	assert_eq!(r, Outcome::Error { error: XcmError::Barrier });
+	assert_eq!(
+		r,
+		Outcome::Incomplete { used: Weight::from_parts(10, 10), error: XcmError::Barrier }
+	);
 
 	let r = XcmExecutor::<TestConfig>::prepare_and_execute(
 		Parent,

polkadot/xcm/xcm-executor/src/lib.rs

@@ -243,7 +243,11 @@ impl<Config: config::Config> ExecuteXcm<Config::RuntimeCall> for XcmExecutor<Con
 				error = ?e,
 				"Barrier blocked execution",
 			);
-			return Outcome::Error { error: XcmError::Barrier }
+
+			return Outcome::Incomplete {
+				used: xcm_weight,         // Weight consumed before the error
+				error: XcmError::Barrier, // The error that occurred
+			};
 		}
 
 		*id = properties.message_id.unwrap_or(*id);

prdoc/pr_7967.prdoc

@@ -0,0 +1,15 @@
+title: Fix XCM Barrier Rejection Handling to Return Incomplete with Weight
+doc:
+- audience: Runtime Dev
+  description: "This PR addresses an issue with the handling of message execution\
+    \ when blocked by the barrier. Instead of returning an `Outcome::Error`, we modify\
+    \ the behaviour to return `Outcome::Incomplete`, which includes the weight consumed\
+    \ up to the point of rejection and the error that caused the blockage.\n\nThis\
+    \ change ensures more accurate weight tracking during message execution, even\
+    \ when interrupted. It improves resource management and aligns the XCM executor\u2019\
+    s behaviour with better error handling practices."
+crates:
+- name: staging-xcm-executor
+  bump: patch
+- name: staging-xcm-builder
+  bump: patch