feat: clean dmpq state at genesis (#279)

* dispatch kill tx

* paseo-local metadata

* chore: address hrmp channels at creation

* clean unnecessary deps

* fix: don't wait for finalisation

* Provide documentation

crates/pop-cli/src/commands/up/parachain.rs

@@ -9,7 +9,7 @@ use cliclack::{
 use console::{Emoji, Style, Term};
 use duct::cmd;
 use pop_common::Status;
-use pop_parachains::{Error, IndexSet, NetworkNode, Zombienet};
+use pop_parachains::{clear_dmpq, Error, IndexSet, NetworkNode, Zombienet};
 use std::{path::PathBuf, time::Duration};
 use tokio::time::sleep;
 
@@ -148,6 +148,28 @@ impl ZombienetCommand {
 				}
 
 				spinner.stop(result);
+
+				// Check for any HRMP specified channels
+				if zombienet.hrmp_channels() {
+					let spinner = cliclack::spinner();
+					spinner.start("Readying channels...");
+					// Allow relay node time to start
+					tokio::time::sleep(Duration::from_secs(10)).await;
+					let relay_endpoint = network.relaychain().nodes()[0].client().await?;
+					let para_ids: Vec<_> =
+						network.parachains().iter().map(|p| p.para_id()).collect();
+					tokio::spawn(async move {
+						if let Err(e) = clear_dmpq(relay_endpoint, &para_ids).await {
+							spinner.stop("");
+							outro_cancel(format!("{e}"))?;
+						}
+						spinner.stop("Channels ready for initialization.");
+						tokio::time::sleep(Duration::from_secs(2)).await;
+						Term::stderr().clear_last_lines(2)?;
+						Ok::<(), Error>(())
+					});
+				}
+
 				tokio::signal::ctrl_c().await?;
 				outro("Done")?;
 			},

crates/pop-parachains/Cargo.toml

@@ -16,6 +16,9 @@ glob.workspace = true
 serde_json.workspace = true
 strum.workspace = true
 strum_macros.workspace = true
+# Subxt dependenices need to be at least 0.37 because of the new SignedExtension
+subxt-signer = { version = "0.37", features = ["subxt", "sr25519"] }
+subxt = "0.37"
 tar.workspace = true
 tempfile.workspace = true
 thiserror.workspace = true

crates/pop-parachains/src/lib.rs

@@ -20,7 +20,7 @@ pub use new_pallet::{create_pallet_template, TemplatePalletConfig};
 pub use new_parachain::instantiate_template_dir;
 pub use templates::{Config, Parachain, Provider};
 pub use up::Zombienet;
-pub use utils::helpers::is_initial_endowment_valid;
+pub use utils::helpers::{clear_dmpq, is_initial_endowment_valid};
 pub use utils::pallet_helpers::resolve_pallet_path;
 /// Information about the Node. External export from Zombienet-SDK.
 pub use zombienet_sdk::NetworkNode;

crates/pop-parachains/src/up/mod.rs

@@ -31,6 +31,8 @@ pub struct Zombienet {
 	relay_chain: RelayChain,
 	/// The configuration required to launch parachains.
 	parachains: IndexMap<u32, Parachain>,
+	/// Whether any HRMP channels are to be pre-opened.
+	hrmp_channels: bool,
 }
 
 impl Zombienet {
@@ -81,7 +83,7 @@ impl Zombienet {
 			cache,
 		)
 		.await?;
-		Ok(Self { network_config, relay_chain, parachains })
+		Ok(Self { network_config, relay_chain, parachains, hrmp_channels: false })
 	}
 
 	/// The binaries required to launch the network.
@@ -268,6 +270,11 @@ impl Zombienet {
 		return Ok(relay::default(version, runtime_version, chain, cache).await?);
 	}
 
+	/// Whether any HRMP channels are to be pre-opened.
+	pub fn hrmp_channels(&self) -> bool {
+		self.hrmp_channels
+	}
+
 	/// Launches the local network.
 	pub async fn spawn(&mut self) -> Result<Network<LocalFileSystem>, Error> {
 		// Symlink polkadot workers
@@ -296,6 +303,7 @@ impl Zombienet {
 		let config = self.network_config.configure(&self.relay_chain, &self.parachains)?;
 		let path = config.path().to_str().expect("temp config file should have a path").into();
 		let network_config = NetworkConfig::load_from_toml(path)?;
+		self.hrmp_channels = !network_config.hrmp_channels().is_empty();
 		Ok(network_config.spawn_native().await?)
 	}
 }

crates/pop-parachains/src/utils/helpers.rs

@@ -6,6 +6,7 @@ use std::{
 	io::{self, stdin, stdout, Write},
 	path::Path,
 };
+use subxt::{ext::sp_core, OnlineClient, PolkadotConfig};
 
 pub(crate) fn sanitize(target: &Path) -> Result<(), Error> {
 	if target.exists() {
@@ -24,6 +25,64 @@ pub(crate) fn sanitize(target: &Path) -> Result<(), Error> {
 	Ok(())
 }
 
+/// Clears the DMPQ state for the given chains.
+/// Assumes pallet-sudo is present in the runtime.
+///
+/// # Arguments
+///
+/// * `client` - Client for the network which state is to be modified.
+/// * `para_ids` - List of ids to build the keys that will be mutated.
+pub async fn clear_dmpq(
+	client: OnlineClient<PolkadotConfig>,
+	para_ids: &[u32],
+) -> Result<(), Box<dyn std::error::Error>> {
+	use subxt_signer::sr25519::dev;
+
+	#[subxt::subxt(runtime_metadata_path = "./src/utils/artifacts/paseo-local.scale")]
+	mod paseo_local {}
+	type RuntimeCall = paseo_local::runtime_types::paseo_runtime::RuntimeCall;
+
+	let sudo = dev::alice();
+
+	// Wait for blocks to be produced.
+	let mut sub = client.blocks().subscribe_finalized().await.unwrap();
+	for _ in 0..2 {
+		sub.next().await;
+	}
+
+	let dmp = sp_core::twox_128("Dmp".as_bytes());
+	let dmp_queues = sp_core::twox_128("DownwardMessageQueues".as_bytes());
+	let dmp_queue_heads = sp_core::twox_128("DownwardMessageQueueHeads".as_bytes());
+
+	let mut clear_dmq_keys = Vec::<Vec<u8>>::new();
+	for id in para_ids {
+		let id = id.to_le_bytes();
+		// DMP Queue Head
+		let mut key = dmp.to_vec();
+		key.extend(&dmp_queue_heads);
+		key.extend(sp_core::twox_64(&id));
+		key.extend(id);
+		clear_dmq_keys.push(key);
+		// DMP Queue
+		let mut key = dmp.to_vec();
+		key.extend(&dmp_queues);
+		key.extend(sp_core::twox_64(&id));
+		key.extend(id);
+		clear_dmq_keys.push(key);
+	}
+
+	// Craft calls to dispatch
+	let kill_storage =
+		RuntimeCall::System(paseo_local::system::Call::kill_storage { keys: clear_dmq_keys });
+	let sudo_call = paseo_local::tx().sudo().sudo(kill_storage);
+
+	// Dispatch and watch tx
+	let _sudo_call_events =
+		client.tx().sign_and_submit_then_watch_default(&sudo_call, &sudo).await?;
+
+	Ok(())
+}
+
 /// Check if the initial endowment input by the user is a valid balance.
 ///
 /// # Arguments
@@ -87,6 +146,7 @@ mod tests {
 	use super::*;
 	use crate::generator::parachain::ChainSpec;
 	use askama::Template;
+	use std::env::var;
 	use tempfile::tempdir;
 
 	#[test]