try-runtime: add cli option --export-proof

utils/frame/try-runtime/cli/Cargo.toml

@@ -14,6 +14,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 clap = { version = "4.0.9", features = ["derive"] }
+hex = { version = "0.4.3", default-features = false }
 log = "0.4.17"
 parity-scale-codec = "3.0.0"
 serde = "1.0.136"

utils/frame/try-runtime/cli/src/commands/execute_block.rs

@@ -212,6 +212,7 @@ where
 		"TryRuntime_execute_block",
 		&payload,
 		full_extensions(),
+		shared.export_proof,
 	)?;
 
 	log::info!(target: LOG_TARGET, "Core_execute_block executed without errors.");

utils/frame/try-runtime/cli/src/commands/follow_chain.rs

@@ -162,6 +162,10 @@ where
 			"TryRuntime_execute_block",
 			(block, command.state_root_check, command.try_state.clone()).encode().as_ref(),
 			full_extensions(),
+			shared
+				.export_proof
+				.as_ref()
+				.map(|path| path.as_path().join(&format!("{}-{}", number, hash))),
 		)?;
 
 		let consumed_weight = <sp_weights::Weight as Decode>::decode(&mut &*encoded_result)

utils/frame/try-runtime/cli/src/commands/on_runtime_upgrade.rs

@@ -78,6 +78,7 @@ where
 		"TryRuntime_on_runtime_upgrade",
 		&[],
 		Default::default(), // we don't really need any extensions here.
+		shared.export_proof,
 	)?;
 
 	let (weight, total_weight) = <(Weight, Weight) as Decode>::decode(&mut &*encoded_result)

utils/frame/try-runtime/cli/src/lib.rs

@@ -132,7 +132,7 @@
 //! added, given the right flag:
 //!
 //! ```ignore
-//! 
+//!
 //! #[cfg(feature = try-runtime)]
 //! fn pre_upgrade() -> Result<Vec<u8>, &'static str> {}
 //!
@@ -431,6 +431,12 @@ pub struct SharedParams {
 	/// State version that is used by the chain.
 	#[arg(long, default_value_t = StateVersion::V1, value_parser = parse::state_version)]
 	pub state_version: StateVersion,
+
+	/// Path to a file to extract the storage proof
+	/// If several blocks are executed, the path is interpreted as a folder
+	/// where one file per block will be written (named `{block_number}-{block_hash}`).
+	#[clap(long, parse(from_os_str))]
+	pub export_proof: Option<PathBuf>,
 }
 
 /// Our `try-runtime` command.
@@ -756,6 +762,7 @@ pub(crate) fn state_machine_call_with_proof<Block: BlockT, D: NativeExecutionDis
 	method: &'static str,
 	data: &[u8],
 	extensions: Extensions,
+	maybe_export_proof: Option<PathBuf>,
 ) -> sc_cli::Result<(OverlayedChanges, Vec<u8>)> {
 	use parity_scale_codec::Encode;
 	use sp_core::hexdisplay::HexDisplay;
@@ -788,6 +795,13 @@ pub(crate) fn state_machine_call_with_proof<Block: BlockT, D: NativeExecutionDis
 	let proof = proving_backend
 		.extract_proof()
 		.expect("A recorder was set and thus, a storage proof can be extracted; qed");
+
+	if let Some(path) = maybe_export_proof {
+		let mut file = std::fs::File::create(path)?;
+		use std::io::Write as _;
+		proof.using_encoded(|encoded_proof| file.write_all(encoded_proof))?;
+	}
+
 	let proof_size = proof.encoded_size();
 	let compact_proof = proof
 		.clone()