From 466d0ab85c432153498bea97d32a2355c6d0d67d Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Sun, 17 Mar 2024 22:43:59 +1300
Subject: [PATCH 01/23] establish_channel_with_system

---
 polkadot/runtime/parachains/src/hrmp.rs | 31 +++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index 42592d9d9f14..ed99d6653465 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -836,6 +836,37 @@ pub mod pallet {
 
 			Ok(())
 		}
+
+		/// TODO write docs
+		#[pallet::call_index(10)]
+		#[pallet::weight(<T as Config>::WeightInfo::establish_system_channel())] // TODO benchmarks
+		pub fn establish_channel_with_system(
+			origin: OriginFor<T>,
+			recipient: ParaId,
+		) -> DispatchResultWithPostInfo {
+			let sender = ensure_parachain(<T as Config>::RuntimeOrigin::from(origin))?;
+
+			ensure!(
+				recipient.is_system(),
+				Error::<T>::ChannelCreationNotAuthorized
+			);
+
+			let config = <configuration::Pallet<T>>::config();
+			let max_message_size = config.hrmp_channel_max_message_size;
+			let max_capacity = config.hrmp_channel_max_capacity;
+
+			Self::init_open_channel(sender, recipient, max_capacity, max_message_size)?;
+			Self::accept_open_channel(recipient, sender)?;
+
+			Self::deposit_event(Event::HrmpSystemChannelOpened {
+				sender,
+				recipient,
+				proposed_max_capacity: max_capacity,
+				proposed_max_message_size: max_message_size,
+			});
+
+			Ok(Pays::No.into())
+		}
 	}
 }
 

From 544e7871e01f632c4c708b37b1db12957b1cce1d Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Sun, 17 Mar 2024 23:24:05 +1300
Subject: [PATCH 02/23] fmt

---
 polkadot/runtime/parachains/src/hrmp.rs | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index ed99d6653465..bf7d141d458b 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -846,10 +846,7 @@ pub mod pallet {
 		) -> DispatchResultWithPostInfo {
 			let sender = ensure_parachain(<T as Config>::RuntimeOrigin::from(origin))?;
 
-			ensure!(
-				recipient.is_system(),
-				Error::<T>::ChannelCreationNotAuthorized
-			);
+			ensure!(recipient.is_system(), Error::<T>::ChannelCreationNotAuthorized);
 
 			let config = <configuration::Pallet<T>>::config();
 			let max_message_size = config.hrmp_channel_max_message_size;

From 1f803422b83e57b21f218f4eb93ca4be5043d1bc Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Mon, 25 Mar 2024 14:25:06 +1300
Subject: [PATCH 03/23] make default channel para to be configuable

---
 polkadot/runtime/parachains/src/hrmp.rs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index bf7d141d458b..b67919a08abb 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -270,6 +270,9 @@ pub mod pallet {
 		/// implementation should be the same as `Balance` as used in the `Configuration`.
 		type Currency: ReservableCurrency<Self::AccountId>;
 
+		/// The default channel size and capacity to use when opening a channel to a system parachain.
+		type DefaultChannelSizeAndCapacityToSystem: Get<(u32, u32)>;
+
 		/// Something that provides the weight of this pallet.
 		type WeightInfo: WeightInfo;
 	}
@@ -848,13 +851,15 @@ pub mod pallet {
 
 			ensure!(recipient.is_system(), Error::<T>::ChannelCreationNotAuthorized);
 
-			let config = <configuration::Pallet<T>>::config();
-			let max_message_size = config.hrmp_channel_max_message_size;
-			let max_capacity = config.hrmp_channel_max_capacity;
+			let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityToSystem::get();
 
+			// create bidirectional channell
 			Self::init_open_channel(sender, recipient, max_capacity, max_message_size)?;
 			Self::accept_open_channel(recipient, sender)?;
 
+			Self::init_open_channel(recipient, sender, max_capacity, max_message_size)?;
+			Self::accept_open_channel(sender, recipient)?;
+
 			Self::deposit_event(Event::HrmpSystemChannelOpened {
 				sender,
 				recipient,

From 30560d2f2e8aa5b1097817e569a3e1ff0491747e Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Mon, 25 Mar 2024 14:36:37 +1300
Subject: [PATCH 04/23] fmt

---
 polkadot/runtime/parachains/src/hrmp.rs | 66 +++++++++++++------------
 1 file changed, 34 insertions(+), 32 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index b67919a08abb..c1aab8d338b0 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -270,7 +270,8 @@ pub mod pallet {
 		/// implementation should be the same as `Balance` as used in the `Configuration`.
 		type Currency: ReservableCurrency<Self::AccountId>;
 
-		/// The default channel size and capacity to use when opening a channel to a system parachain.
+		/// The default channel size and capacity to use when opening a channel to a system
+		/// parachain.
 		type DefaultChannelSizeAndCapacityToSystem: Get<(u32, u32)>;
 
 		/// Something that provides the weight of this pallet.
@@ -567,13 +568,13 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpIngressChannelsIndex::<T>::decode_len(para).unwrap_or_default() <=
-					num_inbound as usize,
+				HrmpIngressChannelsIndex::<T>::decode_len(para).unwrap_or_default()
+					<= num_inbound as usize,
 				Error::<T>::WrongWitness
 			);
 			ensure!(
-				HrmpEgressChannelsIndex::<T>::decode_len(para).unwrap_or_default() <=
-					num_outbound as usize,
+				HrmpEgressChannelsIndex::<T>::decode_len(para).unwrap_or_default()
+					<= num_outbound as usize,
 				Error::<T>::WrongWitness
 			);
 
@@ -595,8 +596,8 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
-					channels,
+				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
+					<= channels,
 				Error::<T>::WrongWitness
 			);
 
@@ -619,8 +620,8 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpCloseChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
-					channels,
+				HrmpCloseChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
+					<= channels,
 				Error::<T>::WrongWitness
 			);
 
@@ -645,8 +646,8 @@ pub mod pallet {
 		) -> DispatchResult {
 			let origin = ensure_parachain(<T as Config>::RuntimeOrigin::from(origin))?;
 			ensure!(
-				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
-					open_requests,
+				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
+					<= open_requests,
 				Error::<T>::WrongWitness
 			);
 			Self::cancel_open_request(origin, channel_id.clone())?;
@@ -779,10 +780,10 @@ pub mod pallet {
 					let current_recipient_deposit = channel.recipient_deposit;
 
 					// nothing to update
-					if current_sender_deposit == new_sender_deposit &&
-						current_recipient_deposit == new_recipient_deposit
+					if current_sender_deposit == new_sender_deposit
+						&& current_recipient_deposit == new_recipient_deposit
 					{
-						return Ok(())
+						return Ok(());
 					}
 
 					// sender
@@ -830,7 +831,7 @@ pub mod pallet {
 					channel.sender_deposit = new_sender_deposit;
 					channel.recipient_deposit = new_recipient_deposit;
 				} else {
-					return Err(Error::<T>::OpenHrmpChannelDoesntExist.into())
+					return Err(Error::<T>::OpenHrmpChannelDoesntExist.into());
 				}
 				Ok(())
 			})?;
@@ -970,7 +971,7 @@ impl<T: Config> Pallet<T> {
 				Some(req_data) => req_data,
 				None => {
 					// Can't normally happen but no need to panic.
-					continue
+					continue;
 				},
 			};
 
@@ -1028,7 +1029,7 @@ impl<T: Config> Pallet<T> {
 	fn process_hrmp_open_channel_requests(config: &HostConfiguration<BlockNumberFor<T>>) {
 		let mut open_req_channels = HrmpOpenChannelRequestsList::<T>::get();
 		if open_req_channels.is_empty() {
-			return
+			return;
 		}
 
 		// iterate the vector starting from the end making our way to the beginning. This way we
@@ -1037,7 +1038,7 @@ impl<T: Config> Pallet<T> {
 		loop {
 			// bail if we've iterated over all items.
 			if idx == 0 {
-				break
+				break;
 			}
 
 			idx -= 1;
@@ -1051,8 +1052,8 @@ impl<T: Config> Pallet<T> {
 			let recipient_deposit = if system_channel { 0 } else { config.hrmp_recipient_deposit };
 
 			if request.confirmed {
-				if <paras::Pallet<T>>::is_valid_para(channel_id.sender) &&
-					<paras::Pallet<T>>::is_valid_para(channel_id.recipient)
+				if <paras::Pallet<T>>::is_valid_para(channel_id.sender)
+					&& <paras::Pallet<T>>::is_valid_para(channel_id.recipient)
 				{
 					HrmpChannels::<T>::insert(
 						&channel_id,
@@ -1149,14 +1150,14 @@ impl<T: Config> Pallet<T> {
 		// (b) However, a parachain cannot read into "the future", therefore the watermark should
 		//     not be greater than the relay-chain context block which the parablock refers to.
 		if new_hrmp_watermark == relay_chain_parent_number {
-			return Ok(())
+			return Ok(());
 		}
 
 		if new_hrmp_watermark > relay_chain_parent_number {
 			return Err(HrmpWatermarkAcceptanceErr::AheadRelayParent {
 				new_watermark: new_hrmp_watermark,
 				relay_chain_parent_number,
-			})
+			});
 		}
 
 		if let Some(last_watermark) = HrmpWatermarks::<T>::get(&recipient) {
@@ -1164,7 +1165,7 @@ impl<T: Config> Pallet<T> {
 				return Err(HrmpWatermarkAcceptanceErr::AdvancementRule {
 					new_watermark: new_hrmp_watermark,
 					last_watermark,
-				})
+				});
 			}
 		}
 
@@ -1179,7 +1180,7 @@ impl<T: Config> Pallet<T> {
 		{
 			return Err(HrmpWatermarkAcceptanceErr::LandsOnBlockWithNoMessages {
 				new_watermark: new_hrmp_watermark,
-			})
+			});
 		}
 		Ok(())
 	}
@@ -1201,7 +1202,7 @@ impl<T: Config> Pallet<T> {
 			return Err(OutboundHrmpAcceptanceErr::MoreMessagesThanPermitted {
 				sent: out_hrmp_msgs.len() as u32,
 				permitted: config.hrmp_max_message_num_per_candidate,
-			})
+			});
 		}
 
 		let mut last_recipient = None::<ParaId>;
@@ -1213,8 +1214,9 @@ impl<T: Config> Pallet<T> {
 				// the messages must be sorted in ascending order and there must be no two messages
 				// sent to the same recipient. Thus we can check that every recipient is strictly
 				// greater than the previous one.
-				Some(last_recipient) if out_msg.recipient <= last_recipient =>
-					return Err(OutboundHrmpAcceptanceErr::NotSorted { idx }),
+				Some(last_recipient) if out_msg.recipient <= last_recipient => {
+					return Err(OutboundHrmpAcceptanceErr::NotSorted { idx })
+				},
 				_ => last_recipient = Some(out_msg.recipient),
 			}
 
@@ -1231,7 +1233,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					msg_size,
 					max_size: channel.max_message_size,
-				})
+				});
 			}
 
 			let new_total_size = channel.total_size + out_msg.data.len() as u32;
@@ -1240,7 +1242,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					total_size: new_total_size,
 					limit: channel.max_total_size,
-				})
+				});
 			}
 
 			let new_msg_count = channel.msg_count + 1;
@@ -1249,7 +1251,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					count: new_msg_count,
 					limit: channel.max_capacity,
-				})
+				});
 			}
 		}
 
@@ -1263,7 +1265,7 @@ impl<T: Config> Pallet<T> {
 
 		for recipient in recipients {
 			let Some(channel) = HrmpChannels::<T>::get(&HrmpChannelId { sender, recipient }) else {
-				continue
+				continue;
 			};
 			remaining.push((
 				recipient,
@@ -1353,7 +1355,7 @@ impl<T: Config> Pallet<T> {
 				None => {
 					// apparently, that since acceptance of this candidate the recipient was
 					// offboarded and the channel no longer exists.
-					continue
+					continue;
 				},
 			};
 

From 1e3b210906836534ae50e78b78f4e08e2d5dcf74 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Mon, 25 Mar 2024 15:03:11 +1300
Subject: [PATCH 05/23] fix

---
 polkadot/runtime/parachains/src/mock.rs  | 2 ++
 polkadot/runtime/rococo/src/lib.rs       | 5 +++++
 polkadot/runtime/test-runtime/src/lib.rs | 2 ++
 polkadot/runtime/westend/src/lib.rs      | 5 +++++
 4 files changed, 14 insertions(+)

diff --git a/polkadot/runtime/parachains/src/mock.rs b/polkadot/runtime/parachains/src/mock.rs
index 7ed62a392e4e..8ccfd3604d47 100644
--- a/polkadot/runtime/parachains/src/mock.rs
+++ b/polkadot/runtime/parachains/src/mock.rs
@@ -248,6 +248,7 @@ impl crate::dmp::Config for Test {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
+	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
 }
 
 impl crate::hrmp::Config for Test {
@@ -255,6 +256,7 @@ impl crate::hrmp::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = frame_system::EnsureRoot<u64>;
 	type Currency = pallet_balances::Pallet<Test>;
+	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
 	type WeightInfo = crate::hrmp::TestWeightInfo;
 }
 
diff --git a/polkadot/runtime/rococo/src/lib.rs b/polkadot/runtime/rococo/src/lib.rs
index 1f51258df089..a4fec430154d 100644
--- a/polkadot/runtime/rococo/src/lib.rs
+++ b/polkadot/runtime/rococo/src/lib.rs
@@ -995,11 +995,16 @@ impl pallet_message_queue::Config for Runtime {
 
 impl parachains_dmp::Config for Runtime {}
 
+parameter_types! {
+	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+}
+
 impl parachains_hrmp::Config for Runtime {
 	type RuntimeOrigin = RuntimeOrigin;
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = EnsureRoot<AccountId>;
 	type Currency = Balances;
+	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
 	type WeightInfo = weights::runtime_parachains_hrmp::WeightInfo<Runtime>;
 }
 
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index 8a3cd9309dbd..3e16940ae7d7 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -554,6 +554,7 @@ impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
+	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
 }
 
 impl parachains_hrmp::Config for Runtime {
@@ -561,6 +562,7 @@ impl parachains_hrmp::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = frame_system::EnsureRoot<AccountId>;
 	type Currency = Balances;
+	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
 	type WeightInfo = parachains_hrmp::TestWeightInfo;
 }
 
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index 15d78706d3a4..e711af8f4862 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -1200,11 +1200,16 @@ impl pallet_message_queue::Config for Runtime {
 
 impl parachains_dmp::Config for Runtime {}
 
+parameter_types! {
+	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+}
+
 impl parachains_hrmp::Config for Runtime {
 	type RuntimeOrigin = RuntimeOrigin;
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = EnsureRoot<AccountId>;
 	type Currency = Balances;
+	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
 	type WeightInfo = weights::runtime_parachains_hrmp::WeightInfo<Self>;
 }
 

From cf94655872862e665904a00039c8339be2e7948a Mon Sep 17 00:00:00 2001
From: Xiliang Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 18:08:57 +1300
Subject: [PATCH 06/23] Update polkadot/runtime/parachains/src/hrmp.rs

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
---
 polkadot/runtime/parachains/src/hrmp.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index c1aab8d338b0..a237b2803b36 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -272,7 +272,7 @@ pub mod pallet {
 
 		/// The default channel size and capacity to use when opening a channel to a system
 		/// parachain.
-		type DefaultChannelSizeAndCapacityToSystem: Get<(u32, u32)>;
+		type DefaultChannelSizeAndCapacityWithSystem: Get<(u32, u32)>;
 
 		/// Something that provides the weight of this pallet.
 		type WeightInfo: WeightInfo;

From b6bc275ced92c3d35a6cb532f6151ba2515f61b6 Mon Sep 17 00:00:00 2001
From: Xiliang Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 18:09:04 +1300
Subject: [PATCH 07/23] Update polkadot/runtime/parachains/src/hrmp.rs

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
---
 polkadot/runtime/parachains/src/hrmp.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index a237b2803b36..46bf0de55905 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -854,7 +854,7 @@ pub mod pallet {
 
 			let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityToSystem::get();
 
-			// create bidirectional channell
+			// create bidirectional channel
 			Self::init_open_channel(sender, recipient, max_capacity, max_message_size)?;
 			Self::accept_open_channel(recipient, sender)?;
 

From 79da6621fc9ef4a37791771a0264a2d04bb30875 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 19:31:02 +1300
Subject: [PATCH 08/23] rename and event

---
 polkadot/runtime/parachains/src/hrmp.rs | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index 46bf0de55905..3a73bfad736b 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -846,24 +846,31 @@ pub mod pallet {
 		#[pallet::weight(<T as Config>::WeightInfo::establish_system_channel())] // TODO benchmarks
 		pub fn establish_channel_with_system(
 			origin: OriginFor<T>,
-			recipient: ParaId,
+			target_system_chain: ParaId,
 		) -> DispatchResultWithPostInfo {
 			let sender = ensure_parachain(<T as Config>::RuntimeOrigin::from(origin))?;
 
-			ensure!(recipient.is_system(), Error::<T>::ChannelCreationNotAuthorized);
+			ensure!(target_system_chain.is_system(), Error::<T>::ChannelCreationNotAuthorized);
 
-			let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityToSystem::get();
+			let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityWithSystem::get();
 
 			// create bidirectional channel
-			Self::init_open_channel(sender, recipient, max_capacity, max_message_size)?;
-			Self::accept_open_channel(recipient, sender)?;
+			Self::init_open_channel(sender, target_system_chain, max_capacity, max_message_size)?;
+			Self::accept_open_channel(target_system_chain, sender)?;
 
-			Self::init_open_channel(recipient, sender, max_capacity, max_message_size)?;
-			Self::accept_open_channel(sender, recipient)?;
+			Self::init_open_channel(target_system_chain, sender, max_capacity, max_message_size)?;
+			Self::accept_open_channel(sender, target_system_chain)?;
 
 			Self::deposit_event(Event::HrmpSystemChannelOpened {
 				sender,
-				recipient,
+				recipient: target_system_chain,
+				proposed_max_capacity: max_capacity,
+				proposed_max_message_size: max_message_size,
+			});
+
+			Self::deposit_event(Event::HrmpSystemChannelOpened {
+				sender: target_system_chain,
+				recipient: sender,
 				proposed_max_capacity: max_capacity,
 				proposed_max_message_size: max_message_size,
 			});

From 1a1df499e1d1b01326eab92961509566e95a1af9 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 19:33:29 +1300
Subject: [PATCH 09/23] fmt

---
 polkadot/runtime/parachains/src/hrmp.rs | 36 ++++++++++++-------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index 3a73bfad736b..c95234fe77d1 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -568,13 +568,13 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpIngressChannelsIndex::<T>::decode_len(para).unwrap_or_default()
-					<= num_inbound as usize,
+				HrmpIngressChannelsIndex::<T>::decode_len(para).unwrap_or_default() <=
+					num_inbound as usize,
 				Error::<T>::WrongWitness
 			);
 			ensure!(
-				HrmpEgressChannelsIndex::<T>::decode_len(para).unwrap_or_default()
-					<= num_outbound as usize,
+				HrmpEgressChannelsIndex::<T>::decode_len(para).unwrap_or_default() <=
+					num_outbound as usize,
 				Error::<T>::WrongWitness
 			);
 
@@ -596,8 +596,8 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
-					<= channels,
+				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
+					channels,
 				Error::<T>::WrongWitness
 			);
 
@@ -620,8 +620,8 @@ pub mod pallet {
 			T::ChannelManager::ensure_origin(origin)?;
 
 			ensure!(
-				HrmpCloseChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
-					<= channels,
+				HrmpCloseChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
+					channels,
 				Error::<T>::WrongWitness
 			);
 
@@ -646,8 +646,8 @@ pub mod pallet {
 		) -> DispatchResult {
 			let origin = ensure_parachain(<T as Config>::RuntimeOrigin::from(origin))?;
 			ensure!(
-				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32
-					<= open_requests,
+				HrmpOpenChannelRequestsList::<T>::decode_len().unwrap_or_default() as u32 <=
+					open_requests,
 				Error::<T>::WrongWitness
 			);
 			Self::cancel_open_request(origin, channel_id.clone())?;
@@ -780,8 +780,8 @@ pub mod pallet {
 					let current_recipient_deposit = channel.recipient_deposit;
 
 					// nothing to update
-					if current_sender_deposit == new_sender_deposit
-						&& current_recipient_deposit == new_recipient_deposit
+					if current_sender_deposit == new_sender_deposit &&
+						current_recipient_deposit == new_recipient_deposit
 					{
 						return Ok(());
 					}
@@ -852,7 +852,8 @@ pub mod pallet {
 
 			ensure!(target_system_chain.is_system(), Error::<T>::ChannelCreationNotAuthorized);
 
-			let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityWithSystem::get();
+			let (max_message_size, max_capacity) =
+				T::DefaultChannelSizeAndCapacityWithSystem::get();
 
 			// create bidirectional channel
 			Self::init_open_channel(sender, target_system_chain, max_capacity, max_message_size)?;
@@ -1059,8 +1060,8 @@ impl<T: Config> Pallet<T> {
 			let recipient_deposit = if system_channel { 0 } else { config.hrmp_recipient_deposit };
 
 			if request.confirmed {
-				if <paras::Pallet<T>>::is_valid_para(channel_id.sender)
-					&& <paras::Pallet<T>>::is_valid_para(channel_id.recipient)
+				if <paras::Pallet<T>>::is_valid_para(channel_id.sender) &&
+					<paras::Pallet<T>>::is_valid_para(channel_id.recipient)
 				{
 					HrmpChannels::<T>::insert(
 						&channel_id,
@@ -1221,9 +1222,8 @@ impl<T: Config> Pallet<T> {
 				// the messages must be sorted in ascending order and there must be no two messages
 				// sent to the same recipient. Thus we can check that every recipient is strictly
 				// greater than the previous one.
-				Some(last_recipient) if out_msg.recipient <= last_recipient => {
-					return Err(OutboundHrmpAcceptanceErr::NotSorted { idx })
-				},
+				Some(last_recipient) if out_msg.recipient <= last_recipient =>
+					return Err(OutboundHrmpAcceptanceErr::NotSorted { idx }),
 				_ => last_recipient = Some(out_msg.recipient),
 			}
 

From 7ed9f54a212dbdf8597b2e6ea35458cd401692bc Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 20:00:45 +1300
Subject: [PATCH 10/23] semi

---
 polkadot/runtime/parachains/src/hrmp.rs | 28 ++++++++++++-------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index c95234fe77d1..cdc8bc113502 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -783,7 +783,7 @@ pub mod pallet {
 					if current_sender_deposit == new_sender_deposit &&
 						current_recipient_deposit == new_recipient_deposit
 					{
-						return Ok(());
+						return Ok(())
 					}
 
 					// sender
@@ -831,7 +831,7 @@ pub mod pallet {
 					channel.sender_deposit = new_sender_deposit;
 					channel.recipient_deposit = new_recipient_deposit;
 				} else {
-					return Err(Error::<T>::OpenHrmpChannelDoesntExist.into());
+					return Err(Error::<T>::OpenHrmpChannelDoesntExist.into())
 				}
 				Ok(())
 			})?;
@@ -979,7 +979,7 @@ impl<T: Config> Pallet<T> {
 				Some(req_data) => req_data,
 				None => {
 					// Can't normally happen but no need to panic.
-					continue;
+					continue
 				},
 			};
 
@@ -1046,7 +1046,7 @@ impl<T: Config> Pallet<T> {
 		loop {
 			// bail if we've iterated over all items.
 			if idx == 0 {
-				break;
+				break
 			}
 
 			idx -= 1;
@@ -1158,14 +1158,14 @@ impl<T: Config> Pallet<T> {
 		// (b) However, a parachain cannot read into "the future", therefore the watermark should
 		//     not be greater than the relay-chain context block which the parablock refers to.
 		if new_hrmp_watermark == relay_chain_parent_number {
-			return Ok(());
+			return Ok(())
 		}
 
 		if new_hrmp_watermark > relay_chain_parent_number {
 			return Err(HrmpWatermarkAcceptanceErr::AheadRelayParent {
 				new_watermark: new_hrmp_watermark,
 				relay_chain_parent_number,
-			});
+			})
 		}
 
 		if let Some(last_watermark) = HrmpWatermarks::<T>::get(&recipient) {
@@ -1173,7 +1173,7 @@ impl<T: Config> Pallet<T> {
 				return Err(HrmpWatermarkAcceptanceErr::AdvancementRule {
 					new_watermark: new_hrmp_watermark,
 					last_watermark,
-				});
+				})
 			}
 		}
 
@@ -1188,7 +1188,7 @@ impl<T: Config> Pallet<T> {
 		{
 			return Err(HrmpWatermarkAcceptanceErr::LandsOnBlockWithNoMessages {
 				new_watermark: new_hrmp_watermark,
-			});
+			})
 		}
 		Ok(())
 	}
@@ -1210,7 +1210,7 @@ impl<T: Config> Pallet<T> {
 			return Err(OutboundHrmpAcceptanceErr::MoreMessagesThanPermitted {
 				sent: out_hrmp_msgs.len() as u32,
 				permitted: config.hrmp_max_message_num_per_candidate,
-			});
+			})
 		}
 
 		let mut last_recipient = None::<ParaId>;
@@ -1240,7 +1240,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					msg_size,
 					max_size: channel.max_message_size,
-				});
+				})
 			}
 
 			let new_total_size = channel.total_size + out_msg.data.len() as u32;
@@ -1249,7 +1249,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					total_size: new_total_size,
 					limit: channel.max_total_size,
-				});
+				})
 			}
 
 			let new_msg_count = channel.msg_count + 1;
@@ -1258,7 +1258,7 @@ impl<T: Config> Pallet<T> {
 					idx,
 					count: new_msg_count,
 					limit: channel.max_capacity,
-				});
+				})
 			}
 		}
 
@@ -1272,7 +1272,7 @@ impl<T: Config> Pallet<T> {
 
 		for recipient in recipients {
 			let Some(channel) = HrmpChannels::<T>::get(&HrmpChannelId { sender, recipient }) else {
-				continue;
+				continue
 			};
 			remaining.push((
 				recipient,
@@ -1362,7 +1362,7 @@ impl<T: Config> Pallet<T> {
 				None => {
 					// apparently, that since acceptance of this candidate the recipient was
 					// offboarded and the channel no longer exists.
-					continue;
+					continue
 				},
 			};
 

From e163fa8cc6d4463a7f1050e9f8853d25c4029ee6 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Tue, 26 Mar 2024 20:01:59 +1300
Subject: [PATCH 11/23] fix

---
 polkadot/runtime/parachains/src/hrmp.rs  | 2 +-
 polkadot/runtime/parachains/src/mock.rs  | 4 ++--
 polkadot/runtime/rococo/src/lib.rs       | 4 ++--
 polkadot/runtime/test-runtime/src/lib.rs | 4 ++--
 polkadot/runtime/westend/src/lib.rs      | 4 ++--
 5 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index cdc8bc113502..c6ceb08d1e89 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -1037,7 +1037,7 @@ impl<T: Config> Pallet<T> {
 	fn process_hrmp_open_channel_requests(config: &HostConfiguration<BlockNumberFor<T>>) {
 		let mut open_req_channels = HrmpOpenChannelRequestsList::<T>::get();
 		if open_req_channels.is_empty() {
-			return;
+			return
 		}
 
 		// iterate the vector starting from the end making our way to the beginning. This way we
diff --git a/polkadot/runtime/parachains/src/mock.rs b/polkadot/runtime/parachains/src/mock.rs
index 8ccfd3604d47..cc13feb698dc 100644
--- a/polkadot/runtime/parachains/src/mock.rs
+++ b/polkadot/runtime/parachains/src/mock.rs
@@ -248,7 +248,7 @@ impl crate::dmp::Config for Test {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
-	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
 }
 
 impl crate::hrmp::Config for Test {
@@ -256,7 +256,7 @@ impl crate::hrmp::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = frame_system::EnsureRoot<u64>;
 	type Currency = pallet_balances::Pallet<Test>;
-	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
+	type DefaultChannelSizeAndCapacityWithSystem = DefaultChannelSizeAndCapacityWithSystem;
 	type WeightInfo = crate::hrmp::TestWeightInfo;
 }
 
diff --git a/polkadot/runtime/rococo/src/lib.rs b/polkadot/runtime/rococo/src/lib.rs
index 2b24008ea67c..02a2127afa33 100644
--- a/polkadot/runtime/rococo/src/lib.rs
+++ b/polkadot/runtime/rococo/src/lib.rs
@@ -996,7 +996,7 @@ impl pallet_message_queue::Config for Runtime {
 impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
-	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
 }
 
 impl parachains_hrmp::Config for Runtime {
@@ -1004,7 +1004,7 @@ impl parachains_hrmp::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = EnsureRoot<AccountId>;
 	type Currency = Balances;
-	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
+	type DefaultChannelSizeAndCapacityWithSystem = DefaultChannelSizeAndCapacityWithSystem;
 	type WeightInfo = weights::runtime_parachains_hrmp::WeightInfo<Runtime>;
 }
 
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index 3e16940ae7d7..f3ebe9296ae2 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -554,7 +554,7 @@ impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
-	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
 }
 
 impl parachains_hrmp::Config for Runtime {
@@ -562,7 +562,7 @@ impl parachains_hrmp::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = frame_system::EnsureRoot<AccountId>;
 	type Currency = Balances;
-	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
+	type DefaultChannelSizeAndCapacityWithSystem = DefaultChannelSizeAndCapacityWithSystem;
 	type WeightInfo = parachains_hrmp::TestWeightInfo;
 }
 
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index 691aed201d87..149ae88ac275 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -1201,7 +1201,7 @@ impl pallet_message_queue::Config for Runtime {
 impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
-	pub const DefaultChannelSizeAndCapacityToSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
 }
 
 impl parachains_hrmp::Config for Runtime {
@@ -1209,7 +1209,7 @@ impl parachains_hrmp::Config for Runtime {
 	type RuntimeEvent = RuntimeEvent;
 	type ChannelManager = EnsureRoot<AccountId>;
 	type Currency = Balances;
-	type DefaultChannelSizeAndCapacityToSystem = DefaultChannelSizeAndCapacityToSystem;
+	type DefaultChannelSizeAndCapacityWithSystem = DefaultChannelSizeAndCapacityWithSystem;
 	type WeightInfo = weights::runtime_parachains_hrmp::WeightInfo<Self>;
 }
 

From 807d088fec0e393bbc77900ceadc776f1ffa183d Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 27 Mar 2024 17:27:53 +1300
Subject: [PATCH 12/23] add benchmarks and docs

---
 polkadot/runtime/parachains/src/hrmp.rs           | 14 ++++++++++++--
 .../runtime/parachains/src/hrmp/benchmarking.rs   | 15 +++++++++++++++
 .../rococo/src/weights/runtime_parachains_hrmp.rs | 10 ++++++++++
 .../src/weights/runtime_parachains_hrmp.rs        | 10 ++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index c6ceb08d1e89..15a711c6ceb5 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -65,6 +65,7 @@ pub trait WeightInfo {
 	fn force_open_hrmp_channel(c: u32) -> Weight;
 	fn establish_system_channel() -> Weight;
 	fn poke_channel_deposits() -> Weight;
+	fn establish_channel_with_system() -> Weight;
 }
 
 /// A weight info that is only suitable for testing.
@@ -104,6 +105,9 @@ impl WeightInfo for TestWeightInfo {
 	fn poke_channel_deposits() -> Weight {
 		Weight::MAX
 	}
+	fn establish_channel_with_system() -> Weight {
+		Weight::MAX
+	}
 }
 
 /// A description of a request to open an HRMP channel.
@@ -841,9 +845,15 @@ pub mod pallet {
 			Ok(())
 		}
 
-		/// TODO write docs
+		/// Establish a bidirectional HRMP channel between a parachain and a system chain.
+		///
+		/// Arguments:
+		///
+		/// - `target_system_chain`: A system chain, `ParaId`.
+		///
+		/// The origin needs to be the parachain origin.
 		#[pallet::call_index(10)]
-		#[pallet::weight(<T as Config>::WeightInfo::establish_system_channel())] // TODO benchmarks
+		#[pallet::weight(<T as Config>::WeightInfo::establish_channel_with_system())]
 		pub fn establish_channel_with_system(
 			origin: OriginFor<T>,
 			target_system_chain: ParaId,
diff --git a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
index c6baf2f30cf5..0aef25ae6205 100644
--- a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
+++ b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
@@ -513,6 +513,21 @@ mod benchmarks {
 		);
 	}
 
+	#[benchmark]
+	fn establish_channel_with_system() {
+		let sender_id = 1u32;
+		let recipient_id: ParaId = 2u32.into();
+
+		let sender_origin: crate::Origin = sender_id.into();
+
+		// make sure para is registered, and has zero balance.
+		register_parachain_with_balance::<T>(sender_id.into(), Zero::zero());
+		register_parachain_with_balance::<T>(recipient_id, Zero::zero());
+
+		#[extrinsic_call]
+		_(sender_origin, recipient_id);
+	}
+
 	impl_benchmark_test_suite!(
 		Hrmp,
 		crate::mock::new_test_ext(crate::hrmp::tests::GenesisConfigBuilder::default().build()),
diff --git a/polkadot/runtime/rococo/src/weights/runtime_parachains_hrmp.rs b/polkadot/runtime/rococo/src/weights/runtime_parachains_hrmp.rs
index 417820e6627f..97b84155b36a 100644
--- a/polkadot/runtime/rococo/src/weights/runtime_parachains_hrmp.rs
+++ b/polkadot/runtime/rococo/src/weights/runtime_parachains_hrmp.rs
@@ -331,4 +331,14 @@ impl<T: frame_system::Config> runtime_parachains::hrmp::WeightInfo for WeightInf
 			.saturating_add(T::DbWeight::get().reads(1))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn establish_channel_with_system() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `417`
+		//  Estimated: `6357`
+		// Minimum execution time: 629_674_000 picoseconds.
+		Weight::from_parts(640_174_000, 0)
+			.saturating_add(Weight::from_parts(0, 6357))
+			.saturating_add(T::DbWeight::get().reads(12))
+			.saturating_add(T::DbWeight::get().writes(8))
+	}
 }
diff --git a/polkadot/runtime/westend/src/weights/runtime_parachains_hrmp.rs b/polkadot/runtime/westend/src/weights/runtime_parachains_hrmp.rs
index 9beb15303d87..3d2ab827b8fd 100644
--- a/polkadot/runtime/westend/src/weights/runtime_parachains_hrmp.rs
+++ b/polkadot/runtime/westend/src/weights/runtime_parachains_hrmp.rs
@@ -324,4 +324,14 @@ impl<T: frame_system::Config> runtime_parachains::hrmp::WeightInfo for WeightInf
 			.saturating_add(T::DbWeight::get().reads(1))
 			.saturating_add(T::DbWeight::get().writes(1))
 	}
+	fn establish_channel_with_system() -> Weight {
+		// Proof Size summary in bytes:
+		//  Measured:  `417`
+		//  Estimated: `6357`
+		// Minimum execution time: 629_674_000 picoseconds.
+		Weight::from_parts(640_174_000, 0)
+			.saturating_add(Weight::from_parts(0, 6357))
+			.saturating_add(T::DbWeight::get().reads(12))
+			.saturating_add(T::DbWeight::get().writes(8))
+	}
 }

From af1f3372fa258f1cc46d28cc57faf4a606ee5d13 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 27 Mar 2024 20:05:41 +1300
Subject: [PATCH 13/23] fix

---
 polkadot/runtime/parachains/src/hrmp/tests.rs | 71 +++++++++++++++++++
 polkadot/runtime/parachains/src/mock.rs       |  2 +-
 2 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/polkadot/runtime/parachains/src/hrmp/tests.rs b/polkadot/runtime/parachains/src/hrmp/tests.rs
index 162c14121601..9e0565b5b0de 100644
--- a/polkadot/runtime/parachains/src/hrmp/tests.rs
+++ b/polkadot/runtime/parachains/src/hrmp/tests.rs
@@ -932,3 +932,74 @@ fn watermark_maxed_out_at_relay_parent() {
 		Hrmp::assert_storage_consistency_exhaustive();
 	});
 }
+
+// #[test]
+// fn open_system_channel_works() {
+// 	let para_a = 1.into();
+// 	let para_b = 3.into();
+
+// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
+// 		// We need both A & B to be registered and live parachains.
+// 		register_parachain(para_a);
+// 		register_parachain(para_b);
+
+// 		run_to_block(5, Some(vec![4, 5]));
+// 		Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b).unwrap();
+// 		Hrmp::assert_storage_consistency_exhaustive();
+// 		assert!(System::events().iter().any(|record| record.event ==
+// 			MockEvent::Hrmp(Event::HrmpSystemChannelOpened {
+// 				sender: para_a,
+// 				recipient: para_b,
+// 				proposed_max_capacity: 2,
+// 				proposed_max_message_size: 8
+// 			})));
+
+// 		// Advance to a block 6, but without session change. That means that the channel has
+// 		// not been created yet.
+// 		run_to_block(6, None);
+// 		assert!(!channel_exists(para_a, para_b));
+// 		Hrmp::assert_storage_consistency_exhaustive();
+
+// 		// Now let the session change happen and thus open the channel.
+// 		run_to_block(8, Some(vec![8]));
+// 		assert!(channel_exists(para_a, para_b));
+// 	});
+// }
+
+// #[test]
+// fn open_system_channel_does_not_work_for_non_system_chains() {
+// 	let para_a = 2001.into();
+// 	let para_b = 2003.into();
+
+// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
+// 		// We need both A & B to be registered and live parachains.
+// 		register_parachain(para_a);
+// 		register_parachain(para_b);
+
+// 		run_to_block(5, Some(vec![4, 5]));
+// 		assert_noop!(
+// 			Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b),
+// 			Error::<Test>::ChannelCreationNotAuthorized
+// 		);
+// 		Hrmp::assert_storage_consistency_exhaustive();
+// 	});
+// }
+
+// #[test]
+// fn open_system_channel_does_not_work_with_one_non_system_chain() {
+// 	let para_a = 1.into();
+// 	let para_b = 2003.into();
+
+// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
+// 		// We need both A & B to be registered and live parachains.
+// 		register_parachain(para_a);
+// 		register_parachain(para_b);
+
+// 		run_to_block(5, Some(vec![4, 5]));
+// 		assert_noop!(
+// 			Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b),
+// 			Error::<Test>::ChannelCreationNotAuthorized
+// 		);
+// 		Hrmp::assert_storage_consistency_exhaustive();
+// 	});
+// }
diff --git a/polkadot/runtime/parachains/src/mock.rs b/polkadot/runtime/parachains/src/mock.rs
index cc13feb698dc..b225c893314a 100644
--- a/polkadot/runtime/parachains/src/mock.rs
+++ b/polkadot/runtime/parachains/src/mock.rs
@@ -248,7 +248,7 @@ impl crate::dmp::Config for Test {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
-	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (1, 4);
 }
 
 impl crate::hrmp::Config for Test {

From debdef65d519b8b86aba9231795d416737f18a6c Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 27 Mar 2024 20:59:11 +1300
Subject: [PATCH 14/23] fix

---
 polkadot/runtime/parachains/src/mock.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/polkadot/runtime/parachains/src/mock.rs b/polkadot/runtime/parachains/src/mock.rs
index b225c893314a..9ae73b87b58b 100644
--- a/polkadot/runtime/parachains/src/mock.rs
+++ b/polkadot/runtime/parachains/src/mock.rs
@@ -248,7 +248,7 @@ impl crate::dmp::Config for Test {}
 
 parameter_types! {
 	pub const FirstMessageFactorPercent: u64 = 100;
-	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (1, 4);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (4, 1);
 }
 
 impl crate::hrmp::Config for Test {

From 2439a77b57c9da4267ef913fa744fea0b4e48e84 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 27 Mar 2024 21:27:25 +1300
Subject: [PATCH 15/23] tests

---
 polkadot/runtime/parachains/src/hrmp/tests.rs | 140 +++++++++---------
 1 file changed, 69 insertions(+), 71 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp/tests.rs b/polkadot/runtime/parachains/src/hrmp/tests.rs
index 9e0565b5b0de..a20fafb9029c 100644
--- a/polkadot/runtime/parachains/src/hrmp/tests.rs
+++ b/polkadot/runtime/parachains/src/hrmp/tests.rs
@@ -24,7 +24,7 @@ use crate::mock::{
 	Configuration, Hrmp, MockGenesisConfig, Paras, ParasShared, RuntimeEvent as MockEvent,
 	RuntimeOrigin, System, Test,
 };
-use frame_support::{assert_noop, assert_ok};
+use frame_support::{assert_noop, assert_ok, error::BadOrigin};
 use primitives::BlockNumber;
 use std::collections::BTreeMap;
 
@@ -933,73 +933,71 @@ fn watermark_maxed_out_at_relay_parent() {
 	});
 }
 
-// #[test]
-// fn open_system_channel_works() {
-// 	let para_a = 1.into();
-// 	let para_b = 3.into();
-
-// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
-// 		// We need both A & B to be registered and live parachains.
-// 		register_parachain(para_a);
-// 		register_parachain(para_b);
-
-// 		run_to_block(5, Some(vec![4, 5]));
-// 		Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b).unwrap();
-// 		Hrmp::assert_storage_consistency_exhaustive();
-// 		assert!(System::events().iter().any(|record| record.event ==
-// 			MockEvent::Hrmp(Event::HrmpSystemChannelOpened {
-// 				sender: para_a,
-// 				recipient: para_b,
-// 				proposed_max_capacity: 2,
-// 				proposed_max_message_size: 8
-// 			})));
-
-// 		// Advance to a block 6, but without session change. That means that the channel has
-// 		// not been created yet.
-// 		run_to_block(6, None);
-// 		assert!(!channel_exists(para_a, para_b));
-// 		Hrmp::assert_storage_consistency_exhaustive();
-
-// 		// Now let the session change happen and thus open the channel.
-// 		run_to_block(8, Some(vec![8]));
-// 		assert!(channel_exists(para_a, para_b));
-// 	});
-// }
-
-// #[test]
-// fn open_system_channel_does_not_work_for_non_system_chains() {
-// 	let para_a = 2001.into();
-// 	let para_b = 2003.into();
-
-// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
-// 		// We need both A & B to be registered and live parachains.
-// 		register_parachain(para_a);
-// 		register_parachain(para_b);
-
-// 		run_to_block(5, Some(vec![4, 5]));
-// 		assert_noop!(
-// 			Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b),
-// 			Error::<Test>::ChannelCreationNotAuthorized
-// 		);
-// 		Hrmp::assert_storage_consistency_exhaustive();
-// 	});
-// }
-
-// #[test]
-// fn open_system_channel_does_not_work_with_one_non_system_chain() {
-// 	let para_a = 1.into();
-// 	let para_b = 2003.into();
-
-// 	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
-// 		// We need both A & B to be registered and live parachains.
-// 		register_parachain(para_a);
-// 		register_parachain(para_b);
-
-// 		run_to_block(5, Some(vec![4, 5]));
-// 		assert_noop!(
-// 			Hrmp::establish_system_channel(RuntimeOrigin::signed(1), para_a, para_b),
-// 			Error::<Test>::ChannelCreationNotAuthorized
-// 		);
-// 		Hrmp::assert_storage_consistency_exhaustive();
-// 	});
-// }
+#[test]
+fn establish_channel_with_system_works() {
+	let para_a = 2000.into();
+	let para_a_origin: crate::Origin = 2000.into();
+	let para_b = 3.into();
+
+	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
+		// We need both A & B to be registered and live parachains.
+		register_parachain(para_a);
+		register_parachain(para_b);
+
+		run_to_block(5, Some(vec![4, 5]));
+		Hrmp::establish_channel_with_system(para_a_origin.into(), para_b).unwrap();
+		Hrmp::assert_storage_consistency_exhaustive();
+		assert!(System::events().iter().any(|record| record.event ==
+			MockEvent::Hrmp(Event::HrmpSystemChannelOpened {
+				sender: para_a,
+				recipient: para_b,
+				proposed_max_capacity: 1,
+				proposed_max_message_size: 4
+			})));
+
+		assert!(System::events().iter().any(|record| record.event ==
+			MockEvent::Hrmp(Event::HrmpSystemChannelOpened {
+				sender: para_b,
+				recipient: para_a,
+				proposed_max_capacity: 1,
+				proposed_max_message_size: 4
+			})));
+
+		// Advance to a block 6, but without session change. That means that the channel has
+		// not been created yet.
+		run_to_block(6, None);
+		assert!(!channel_exists(para_a, para_b));
+		assert!(!channel_exists(para_b, para_a));
+		Hrmp::assert_storage_consistency_exhaustive();
+
+		// Now let the session change happen and thus open the channel.
+		run_to_block(8, Some(vec![8]));
+		assert!(channel_exists(para_a, para_b));
+		assert!(channel_exists(para_b, para_a));
+		Hrmp::assert_storage_consistency_exhaustive();
+	});
+}
+
+#[test]
+fn establish_channel_with_system_with_invalid_args() {
+	let para_a = 2001.into();
+	let para_a_origin: crate::Origin = 2000.into();
+	let para_b = 2003.into();
+
+	new_test_ext(GenesisConfigBuilder::default().build()).execute_with(|| {
+		// We need both A & B to be registered and live parachains.
+		register_parachain(para_a);
+		register_parachain(para_b);
+
+		run_to_block(5, Some(vec![4, 5]));
+		assert_noop!(
+			Hrmp::establish_channel_with_system(RuntimeOrigin::signed(1), para_b),
+			BadOrigin
+		);
+		assert_noop!(
+			Hrmp::establish_channel_with_system(para_a_origin.into(), para_b),
+			Error::<Test>::ChannelCreationNotAuthorized
+		);
+		Hrmp::assert_storage_consistency_exhaustive();
+	});
+}

From f68454ab57282843f5ec00a2de9f78d06556d6c3 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 27 Mar 2024 21:37:09 +1300
Subject: [PATCH 16/23] prdoc

---
 prdoc/pr_3721.prdoc | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 prdoc/pr_3721.prdoc

diff --git a/prdoc/pr_3721.prdoc b/prdoc/pr_3721.prdoc
new file mode 100644
index 000000000000..42444beb7bc1
--- /dev/null
+++ b/prdoc/pr_3721.prdoc
@@ -0,0 +1,12 @@
+# Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
+# See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
+
+title: New call `hrmp.establish_channel_with_system` to allow parachains to establish a channel with the system parachain
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR adds a new call `hrmp.establish_channel_with_system` that allows a parachain origin to open a bidirectional channel with a system parachain.
+
+crates: 
+  - name: polkadot-runtime-parachains

From 6807729e68b523a69f2acfabed316d78324ca2ed Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Thu, 28 Mar 2024 14:31:03 +1300
Subject: [PATCH 17/23] fix westend bench

---
 polkadot/runtime/westend/src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index 7184f72fefc1..fb15ec2f7bcb 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -1203,7 +1203,7 @@ impl pallet_message_queue::Config for Runtime {
 impl parachains_dmp::Config for Runtime {}
 
 parameter_types! {
-	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (51200, 500);
+	pub const DefaultChannelSizeAndCapacityWithSystem: (u32, u32) = (4096, 4);
 }
 
 impl parachains_hrmp::Config for Runtime {

From 48bbe0877a3585bba7f0f242b9fef0a02075fd23 Mon Sep 17 00:00:00 2001
From: Xiliang Chen <xlchen1291@gmail.com>
Date: Wed, 3 Apr 2024 14:00:40 +1300
Subject: [PATCH 18/23] Update prdoc/pr_3721.prdoc

Co-authored-by: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
---
 prdoc/pr_3721.prdoc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/prdoc/pr_3721.prdoc b/prdoc/pr_3721.prdoc
index 42444beb7bc1..771f316a2b35 100644
--- a/prdoc/pr_3721.prdoc
+++ b/prdoc/pr_3721.prdoc
@@ -1,7 +1,7 @@
 # Schema: Polkadot SDK PRDoc Schema (prdoc) v1.0.0
 # See doc at https://raw.githubusercontent.com/paritytech/polkadot-sdk/master/prdoc/schema_user.json
 
-title: New call `hrmp.establish_channel_with_system` to allow parachains to establish a channel with the system parachain
+title: New call `hrmp.establish_channel_with_system` to allow parachains to establish a channel with a system parachain
 
 doc:
   - audience: Runtime Dev

From 2ccb92692e88b66aaf84b7ba37c507f6df17952e Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 3 Apr 2024 15:25:02 +1300
Subject: [PATCH 19/23] test

---
 polkadot/runtime/parachains/src/hrmp.rs       |  2 +-
 .../parachains/src/hrmp/benchmarking.rs       | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/polkadot/runtime/parachains/src/hrmp.rs b/polkadot/runtime/parachains/src/hrmp.rs
index 39dc73a3a8de..2ed86b968b2e 100644
--- a/polkadot/runtime/parachains/src/hrmp.rs
+++ b/polkadot/runtime/parachains/src/hrmp.rs
@@ -305,7 +305,7 @@ pub mod pallet {
 			proposed_max_capacity: u32,
 			proposed_max_message_size: u32,
 		},
-		/// An HRMP channel was opened between two system chains.
+		/// An HRMP channel was opened with a system chain.
 		HrmpSystemChannelOpened {
 			sender: ParaId,
 			recipient: ParaId,
diff --git a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
index 0aef25ae6205..857f95d83381 100644
--- a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
+++ b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
@@ -50,6 +50,15 @@ fn assert_last_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	assert_eq!(event, &system_event);
 }
 
+fn assert_has_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
+	let events = frame_system::Pallet::<T>::events();
+	let system_event: <T as frame_system::Config>::RuntimeEvent = generic_event.into();
+
+	println!("events: {:?}", events);
+
+	assert!(events.iter().any(|record| record.event == system_event));
+}
+
 /// Enumerates the phase in the setup process of a channel between two parachains.
 enum ParachainSetupStep {
 	/// A channel open has been requested
@@ -526,6 +535,29 @@ mod benchmarks {
 
 		#[extrinsic_call]
 		_(sender_origin, recipient_id);
+
+		let (max_message_size, max_capacity) =
+				T::DefaultChannelSizeAndCapacityWithSystem::get();
+
+		assert_has_event::<T>(
+			Event::<T>::HrmpSystemChannelOpened {
+				sender: sender_id.into(),
+			recipient: recipient_id,
+				proposed_max_capacity: max_capacity,
+				proposed_max_message_size: max_message_size,
+			}
+			.into(),
+		);
+
+		assert_has_event::<T>(
+			Event::<T>::HrmpSystemChannelOpened {
+				sender: recipient_id,
+				recipient: sender_id.into(),
+				proposed_max_capacity: max_capacity,
+				proposed_max_message_size: max_message_size,
+			}
+			.into(),
+		);
 	}
 
 	impl_benchmark_test_suite!(

From 212179cb990d3155463324ca59e8ed5d8ed82fc1 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Wed, 3 Apr 2024 15:30:28 +1300
Subject: [PATCH 20/23] fmt

---
 .../runtime/parachains/src/hrmp/benchmarking.rs     | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
index 857f95d83381..5af8e5ae9b77 100644
--- a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
+++ b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
@@ -110,24 +110,24 @@ where
 	));
 
 	if matches!(until, ParachainSetupStep::Requested) {
-		return output
+		return output;
 	}
 
 	assert_ok!(Hrmp::<T>::hrmp_accept_open_channel(recipient_origin.into(), sender));
 	if matches!(until, ParachainSetupStep::Accepted) {
-		return output
+		return output;
 	}
 
 	Hrmp::<T>::process_hrmp_open_channel_requests(&Configuration::<T>::config());
 	if matches!(until, ParachainSetupStep::Established) {
-		return output
+		return output;
 	}
 
 	let channel_id = HrmpChannelId { sender, recipient };
 	assert_ok!(Hrmp::<T>::hrmp_close_channel(sender_origin.clone().into(), channel_id));
 	if matches!(until, ParachainSetupStep::CloseRequested) {
 		// NOTE: this is just for expressiveness, otherwise the if-statement is 100% useless.
-		return output
+		return output;
 	}
 
 	output
@@ -536,13 +536,12 @@ mod benchmarks {
 		#[extrinsic_call]
 		_(sender_origin, recipient_id);
 
-		let (max_message_size, max_capacity) =
-				T::DefaultChannelSizeAndCapacityWithSystem::get();
+		let (max_message_size, max_capacity) = T::DefaultChannelSizeAndCapacityWithSystem::get();
 
 		assert_has_event::<T>(
 			Event::<T>::HrmpSystemChannelOpened {
 				sender: sender_id.into(),
-			recipient: recipient_id,
+				recipient: recipient_id,
 				proposed_max_capacity: max_capacity,
 				proposed_max_message_size: max_message_size,
 			}

From 35db15ab2a8f50f9c0f73b0916a3db705099d701 Mon Sep 17 00:00:00 2001
From: Xiliang Chen <xlchen1291@gmail.com>
Date: Wed, 3 Apr 2024 22:00:52 +1300
Subject: [PATCH 21/23] Update prdoc/pr_3721.prdoc

Co-authored-by: Adrian Catangiu <adrian@parity.io>
---
 prdoc/pr_3721.prdoc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/prdoc/pr_3721.prdoc b/prdoc/pr_3721.prdoc
index 771f316a2b35..be36103c4742 100644
--- a/prdoc/pr_3721.prdoc
+++ b/prdoc/pr_3721.prdoc
@@ -9,4 +9,5 @@ doc:
       This PR adds a new call `hrmp.establish_channel_with_system` that allows a parachain origin to open a bidirectional channel with a system parachain.
 
 crates: 
-  - name: polkadot-runtime-parachains
+- name: polkadot-runtime-parachains
+  bump: minor

From 59f8cc24ff5cd753d11a0d159a9d000fd0320619 Mon Sep 17 00:00:00 2001
From: Bryan Chen <xlchen1291@gmail.com>
Date: Fri, 12 Apr 2024 17:21:48 +1200
Subject: [PATCH 22/23] remove debug print

---
 polkadot/runtime/parachains/src/hrmp/benchmarking.rs | 2 --
 substrate/frame/support/src/traits/randomness.rs     | 2 +-
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
index 820be9b01a50..3b32a8b95195 100644
--- a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
+++ b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
@@ -54,8 +54,6 @@ fn assert_has_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::RuntimeEvent = generic_event.into();
 
-	println!("events: {:?}", events);
-
 	assert!(events.iter().any(|record| record.event == system_event));
 }
 
diff --git a/substrate/frame/support/src/traits/randomness.rs b/substrate/frame/support/src/traits/randomness.rs
index 3666a486465f..178c0f70ad1e 100644
--- a/substrate/frame/support/src/traits/randomness.rs
+++ b/substrate/frame/support/src/traits/randomness.rs
@@ -40,7 +40,7 @@ pub trait Randomness<Output, BlockNumber> {
 	/// Get the basic random seed.
 	///
 	/// In general you won't want to use this, but rather `Self::random` which allows
-	/// you to give a subject for the random result and whose value will be
+	/// you to give a subject for the random result and whose value will eb
 	/// independently low-influence random from any other such seeds.
 	///
 	/// NOTE: The returned seed should only be used to distinguish commitments made before

From c92d726e965bb2dab4972470765b1f5da52403f0 Mon Sep 17 00:00:00 2001
From: joe petrowski <25483142+joepetrowski@users.noreply.github.com>
Date: Fri, 12 Apr 2024 07:39:36 +0200
Subject: [PATCH 23/23] Apply suggestions from code review

---
 polkadot/runtime/parachains/src/hrmp/benchmarking.rs | 8 ++++----
 substrate/frame/support/src/traits/randomness.rs     | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
index 3b32a8b95195..8bf444e647e2 100644
--- a/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
+++ b/polkadot/runtime/parachains/src/hrmp/benchmarking.rs
@@ -110,24 +110,24 @@ where
 	));
 
 	if matches!(until, ParachainSetupStep::Requested) {
-		return output;
+		return output
 	}
 
 	assert_ok!(Hrmp::<T>::hrmp_accept_open_channel(recipient_origin.into(), sender));
 	if matches!(until, ParachainSetupStep::Accepted) {
-		return output;
+		return output
 	}
 
 	Hrmp::<T>::process_hrmp_open_channel_requests(&configuration::ActiveConfig::<T>::get());
 	if matches!(until, ParachainSetupStep::Established) {
-		return output;
+		return output
 	}
 
 	let channel_id = HrmpChannelId { sender, recipient };
 	assert_ok!(Hrmp::<T>::hrmp_close_channel(sender_origin.clone().into(), channel_id));
 	if matches!(until, ParachainSetupStep::CloseRequested) {
 		// NOTE: this is just for expressiveness, otherwise the if-statement is 100% useless.
-		return output;
+		return output
 	}
 
 	output
diff --git a/substrate/frame/support/src/traits/randomness.rs b/substrate/frame/support/src/traits/randomness.rs
index 178c0f70ad1e..3666a486465f 100644
--- a/substrate/frame/support/src/traits/randomness.rs
+++ b/substrate/frame/support/src/traits/randomness.rs
@@ -40,7 +40,7 @@ pub trait Randomness<Output, BlockNumber> {
 	/// Get the basic random seed.
 	///
 	/// In general you won't want to use this, but rather `Self::random` which allows
-	/// you to give a subject for the random result and whose value will eb
+	/// you to give a subject for the random result and whose value will be
 	/// independently low-influence random from any other such seeds.
 	///
 	/// NOTE: The returned seed should only be used to distinguish commitments made before