From c8e76ad60936283e379f791c815bd980c199555f Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Mon, 27 May 2024 19:24:22 +0200
Subject: [PATCH 01/10] Chain spec builder substitute

---
 Cargo.lock                                    |  4 ++
 .../bin/utils/chain-spec-builder/Cargo.toml   |  4 ++
 .../bin/utils/chain-spec-builder/bin/main.rs  | 38 +++++++++++++---
 .../bin/utils/chain-spec-builder/src/lib.rs   | 43 ++++++++++++++++++-
 substrate/client/chain-spec/src/chain_spec.rs | 10 +++++
 substrate/client/chain-spec/src/lib.rs        |  4 +-
 6 files changed, 94 insertions(+), 9 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 82dfd34c2528..c28c67cc4033 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -20525,7 +20525,11 @@ dependencies = [
  "clap 4.5.3",
  "log",
  "sc-chain-spec",
+ "sc-service",
+ "serde",
  "serde_json",
+ "sp-core",
+ "sp-runtime",
  "sp-tracing 16.0.0",
 ]
 
diff --git a/substrate/bin/utils/chain-spec-builder/Cargo.toml b/substrate/bin/utils/chain-spec-builder/Cargo.toml
index 5c8a3ab4e89a..0f3cd90d8d67 100644
--- a/substrate/bin/utils/chain-spec-builder/Cargo.toml
+++ b/substrate/bin/utils/chain-spec-builder/Cargo.toml
@@ -28,3 +28,7 @@ log = { workspace = true, default-features = true }
 sc-chain-spec = { path = "../../../client/chain-spec" }
 serde_json = { workspace = true, default-features = true }
 sp-tracing = { path = "../../../primitives/tracing" }
+serde = { features = ["derive"], workspace = true, default-features = true }
+sp-runtime = { path = "../../../primitives/runtime" }
+sp-core = { path = "../../../primitives/core" }
+sc-service = { path = "../../../client/service", default-features = false }
diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index 8d6425a46c77..ce5ca70eb3da 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -17,12 +17,13 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use chain_spec_builder::{
-	generate_chain_spec_for_runtime, ChainSpecBuilder, ChainSpecBuilderCmd, ConvertToRawCmd,
-	DisplayPresetCmd, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
+	generate_chain_spec_for_runtime, AddCodeSubstituteCmd, ChainSpecBuilder, ChainSpecBuilderCmd,
+	ConvertToRawCmd, DisplayPresetCmd, Extensions, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
 };
 use clap::Parser;
 use sc_chain_spec::{
-	update_code_in_json_chain_spec, GenericChainSpec, GenesisConfigBuilderRuntimeCaller,
+	set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec, GenericChainSpec,
+	GenesisConfigBuilderRuntimeCaller,
 };
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
@@ -50,7 +51,8 @@ fn inner_main() -> Result<(), String> {
 			ref input_chain_spec,
 			ref runtime_wasm_path,
 		}) => {
-			let chain_spec = GenericChainSpec::<()>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec =
+				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
 
 			let mut chain_spec_json =
 				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(false)?)
@@ -65,8 +67,31 @@ fn inner_main() -> Result<(), String> {
 				.map_err(|e| format!("to pretty failed: {e}"))?;
 			fs::write(chain_spec_path, chain_spec_json).map_err(|err| err.to_string())?;
 		},
+		ChainSpecBuilderCmd::AddCodeSubstitute(AddCodeSubstituteCmd {
+			ref input_chain_spec,
+			ref runtime_wasm_path,
+			block_height,
+		}) => {
+			let chain_spec =
+				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
+
+			let mut chain_spec_json =
+				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(false)?)
+					.map_err(|e| format!("Conversion to json failed: {e}"))?;
+
+			set_code_substitute_in_json_chain_spec(
+				&mut chain_spec_json,
+				&fs::read(runtime_wasm_path.as_path())
+					.map_err(|e| format!("Wasm blob file could not be read: {e}"))?[..],
+				block_height,
+			);
+			let chain_spec_json = serde_json::to_string_pretty(&chain_spec_json)
+				.map_err(|e| format!("to pretty failed: {e}"))?;
+			fs::write(chain_spec_path, chain_spec_json).map_err(|err| err.to_string())?;
+		},
 		ChainSpecBuilderCmd::ConvertToRaw(ConvertToRawCmd { ref input_chain_spec }) => {
-			let chain_spec = GenericChainSpec::<()>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec =
+				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
 
 			let chain_spec_json =
 				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(true)?)
@@ -77,7 +102,8 @@ fn inner_main() -> Result<(), String> {
 			fs::write(chain_spec_path, chain_spec_json).map_err(|err| err.to_string())?;
 		},
 		ChainSpecBuilderCmd::Verify(VerifyCmd { ref input_chain_spec }) => {
-			let chain_spec = GenericChainSpec::<()>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec =
+				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
 			let _ = serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(true)?)
 				.map_err(|e| format!("Conversion to json failed: {e}"))?;
 		},
diff --git a/substrate/bin/utils/chain-spec-builder/src/lib.rs b/substrate/bin/utils/chain-spec-builder/src/lib.rs
index 7982da76227a..78a8f21a33e9 100644
--- a/substrate/bin/utils/chain-spec-builder/src/lib.rs
+++ b/substrate/bin/utils/chain-spec-builder/src/lib.rs
@@ -120,7 +120,10 @@
 use std::{fs, path::PathBuf};
 
 use clap::{Parser, Subcommand};
-use sc_chain_spec::{GenericChainSpec, GenesisConfigBuilderRuntimeCaller};
+use sc_chain_spec::{
+	ChainSpecExtension, ChainSpecGroup, GenericChainSpec, GenesisConfigBuilderRuntimeCaller,
+};
+use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
 /// A utility to easily create a chain spec definition.
@@ -143,6 +146,7 @@ pub enum ChainSpecBuilderCmd {
 	ConvertToRaw(ConvertToRawCmd),
 	ListPresets(ListPresetsCmd),
 	DisplayPreset(DisplayPresetCmd),
+	AddCodeSubstitute(AddCodeSubstituteCmd),
 }
 
 /// Create a new chain spec by interacting with the provided runtime wasm blob.
@@ -214,6 +218,20 @@ pub struct UpdateCodeCmd {
 	pub runtime_wasm_path: PathBuf,
 }
 
+/// Add a code substitute in the chain spec.
+///
+/// The `codeSubstitute` object of the chain spec will be updated with the block height as key and
+/// runtime code as value. This operation supports both plain and raw formats.
+#[derive(Parser, Debug, Clone)]
+pub struct AddCodeSubstituteCmd {
+	/// Chain spec to be updated.
+	pub input_chain_spec: PathBuf,
+	/// New runtime wasm blob that should replace the existing code.
+	pub runtime_wasm_path: PathBuf,
+	/// The block height at which the code should be substituted.
+	pub block_height: u64,
+}
+
 /// Converts the given chain spec into the raw format.
 #[derive(Parser, Debug, Clone)]
 pub struct ConvertToRawCmd {
@@ -240,6 +258,29 @@ pub struct DisplayPresetCmd {
 	pub preset_name: Option<String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+pub struct Extensions {
+	/// The relay chain of the Parachain.
+	#[serde(alias = "relayChain", alias = "RelayChain")]
+	pub relay_chain: String,
+	/// The id of the Parachain.
+	#[serde(alias = "paraId", alias = "ParaId")]
+	pub para_id: u32,
+}
+
+impl Extensions {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}
+
+impl sp_runtime::BuildStorage for Extensions {
+	/// Assimilate the storage for this module into pre-existing overlays.
+	fn assimilate_storage(&self, storage: &mut sp_core::storage::Storage) -> Result<(), String> {
+		unimplemented!();
+	}
+}
 /// Verifies the provided input chain spec.
 ///
 /// Silently checks if given input chain spec can be converted to raw. It allows to check if all
diff --git a/substrate/client/chain-spec/src/chain_spec.rs b/substrate/client/chain-spec/src/chain_spec.rs
index a9cdce4bf955..b80cf6535a4f 100644
--- a/substrate/client/chain-spec/src/chain_spec.rs
+++ b/substrate/client/chain-spec/src/chain_spec.rs
@@ -863,6 +863,16 @@ pub fn update_code_in_json_chain_spec(chain_spec: &mut json::Value, code: &[u8])
 	}
 }
 
+/// This function sets a codeSubstitute in the chain spec.
+pub fn set_code_substitute_in_json_chain_spec(
+	chain_spec: &mut json::Value,
+	code: &[u8],
+	block_height: u64,
+) {
+	let substitutes = json::json!({"codeSubstitutes":{ &block_height.to_string(): sp_core::bytes::to_hex(code, false) }});
+	crate::json_patch::merge(chain_spec, substitutes);
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
diff --git a/substrate/client/chain-spec/src/lib.rs b/substrate/client/chain-spec/src/lib.rs
index abe01dafd924..ac7f755cb129 100644
--- a/substrate/client/chain-spec/src/lib.rs
+++ b/substrate/client/chain-spec/src/lib.rs
@@ -329,8 +329,8 @@ pub mod json_patch;
 
 pub use self::{
 	chain_spec::{
-		update_code_in_json_chain_spec, ChainSpec as GenericChainSpec, ChainSpecBuilder,
-		NoExtension,
+		set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec,
+		ChainSpec as GenericChainSpec, ChainSpecBuilder, NoExtension,
 	},
 	extension::{get_extension, get_extension_mut, Extension, Fork, Forks, GetExtension, Group},
 	genesis_block::{

From c45be3a209c83796661393908f9589c7ad30aa5f Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Mon, 3 Jun 2024 15:18:55 +0200
Subject: [PATCH 02/10] Extract chain-spec-extension

---
 Cargo.lock                                    | 14 ++++++-
 Cargo.toml                                    |  1 +
 .../client/chain-spec-extension/Cargo.toml    | 14 +++++++
 .../client/chain-spec-extension/src/lib.rs    | 38 +++++++++++++++++++
 cumulus/polkadot-parachain/Cargo.toml         |  2 +-
 .../polkadot-parachain/src/chain_spec/mod.rs  | 21 +---------
 cumulus/polkadot-parachain/src/cli.rs         |  3 +-
 cumulus/polkadot-parachain/src/command.rs     |  2 +-
 cumulus/test/service/Cargo.toml               |  1 +
 cumulus/test/service/src/chain_spec.rs        | 20 ++--------
 cumulus/test/service/src/main.rs              |  7 ++--
 .../bin/utils/chain-spec-builder/Cargo.toml   |  1 +
 .../bin/utils/chain-spec-builder/bin/main.rs  | 17 ++++-----
 .../bin/utils/chain-spec-builder/src/lib.rs   | 26 +------------
 templates/parachain/node/Cargo.toml           |  2 +-
 templates/parachain/node/src/chain_spec.rs    | 21 +---------
 templates/parachain/node/src/cli.rs           |  4 +-
 templates/parachain/node/src/command.rs       |  3 +-
 18 files changed, 96 insertions(+), 101 deletions(-)
 create mode 100644 cumulus/client/chain-spec-extension/Cargo.toml
 create mode 100644 cumulus/client/chain-spec-extension/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index c28c67cc4033..b88da679808e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3583,6 +3583,14 @@ dependencies = [
  "cipher 0.4.4",
 ]
 
+[[package]]
+name = "cumulus-client-chain-spec-extension"
+version = "0.1.0"
+dependencies = [
+ "sc-chain-spec",
+ "serde",
+]
+
 [[package]]
 name = "cumulus-client-cli"
 version = "0.7.0"
@@ -4367,6 +4375,7 @@ dependencies = [
  "async-trait",
  "clap 4.5.3",
  "criterion",
+ "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -11706,6 +11715,7 @@ version = "0.0.0"
 dependencies = [
  "clap 4.5.3",
  "color-print",
+ "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -11742,7 +11752,6 @@ dependencies = [
  "sc-tracing",
  "sc-transaction-pool",
  "sc-transaction-pool-api",
- "serde",
  "serde_json",
  "sp-api",
  "sp-block-builder",
@@ -13541,6 +13550,7 @@ dependencies = [
  "contracts-rococo-runtime",
  "coretime-rococo-runtime",
  "coretime-westend-runtime",
+ "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -13591,7 +13601,6 @@ dependencies = [
  "sc-transaction-pool",
  "sc-transaction-pool-api",
  "seedling-runtime",
- "serde",
  "serde_json",
  "shell-runtime",
  "sp-api",
@@ -20523,6 +20532,7 @@ name = "staging-chain-spec-builder"
 version = "3.0.0"
 dependencies = [
  "clap 4.5.3",
+ "cumulus-client-chain-spec-extension",
  "log",
  "sc-chain-spec",
  "sc-service",
diff --git a/Cargo.toml b/Cargo.toml
index d6099e420f91..0696580d8960 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -67,6 +67,7 @@ members = [
 	"cumulus/client/consensus/common",
 	"cumulus/client/consensus/proposer",
 	"cumulus/client/consensus/relay-chain",
+	"cumulus/client/chain-spec-extension",
 	"cumulus/client/network",
 	"cumulus/client/parachain-inherent",
 	"cumulus/client/pov-recovery",
diff --git a/cumulus/client/chain-spec-extension/Cargo.toml b/cumulus/client/chain-spec-extension/Cargo.toml
new file mode 100644
index 000000000000..7d27f944afed
--- /dev/null
+++ b/cumulus/client/chain-spec-extension/Cargo.toml
@@ -0,0 +1,14 @@
+[package]
+name = "cumulus-client-chain-spec-extension"
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+description = "Parachain chain-spec extension."
+license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
+
+[lints]
+workspace = true
+
+[dependencies]
+sc-chain-spec = { path = "../../../substrate/client/chain-spec" }
+serde = { features = ["derive"], workspace = true, default-features = true }
diff --git a/cumulus/client/chain-spec-extension/src/lib.rs b/cumulus/client/chain-spec-extension/src/lib.rs
new file mode 100644
index 000000000000..495e084fd9cb
--- /dev/null
+++ b/cumulus/client/chain-spec-extension/src/lib.rs
@@ -0,0 +1,38 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Cumulus.
+
+// Cumulus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Cumulus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Chain spec extension for parachains.
+
+use sc_chain_spec::{ChainSpec, ChainSpecExtension, ChainSpecGroup};
+use serde::{Deserialize, Serialize};
+
+/// The extensions for the [`ChainSpec`].
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+pub struct Extensions {
+	/// The relay chain of the Parachain.
+	#[serde(alias = "relayChain", alias = "RelayChain")]
+	pub relay_chain: String,
+	/// The id of the Parachain.
+	#[serde(alias = "paraId", alias = "ParaId")]
+	pub para_id: u32,
+}
+
+impl Extensions {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}
diff --git a/cumulus/polkadot-parachain/Cargo.toml b/cumulus/polkadot-parachain/Cargo.toml
index a22606edb6c5..734fd07648a2 100644
--- a/cumulus/polkadot-parachain/Cargo.toml
+++ b/cumulus/polkadot-parachain/Cargo.toml
@@ -21,7 +21,6 @@ codec = { package = "parity-scale-codec", version = "3.6.12" }
 futures = "0.3.28"
 hex-literal = "0.4.1"
 log = { workspace = true, default-features = true }
-serde = { features = ["derive"], workspace = true, default-features = true }
 serde_json = { workspace = true, default-features = true }
 
 # Local
@@ -112,6 +111,7 @@ cumulus-primitives-aura = { path = "../primitives/aura" }
 cumulus-primitives-core = { path = "../primitives/core" }
 cumulus-relay-chain-interface = { path = "../client/relay-chain-interface" }
 color-print = "0.3.4"
+cumulus-client-chain-spec-extension = { path = "../client/chain-spec-extension" }
 
 [build-dependencies]
 substrate-build-script-utils = { path = "../../substrate/utils/build-script-utils" }
diff --git a/cumulus/polkadot-parachain/src/chain_spec/mod.rs b/cumulus/polkadot-parachain/src/chain_spec/mod.rs
index 136a19e3166b..0b374b64dd91 100644
--- a/cumulus/polkadot-parachain/src/chain_spec/mod.rs
+++ b/cumulus/polkadot-parachain/src/chain_spec/mod.rs
@@ -14,9 +14,8 @@
 // You should have received a copy of the GNU General Public License
 // along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
 
+use cumulus_client_chain_spec_extension::Extensions;
 use parachains_common::{AccountId, Signature};
-use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
-use serde::{Deserialize, Serialize};
 use sp_core::{Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -35,24 +34,6 @@ pub mod shell;
 /// The default XCM version to set in genesis config.
 const SAFE_XCM_VERSION: u32 = xcm::prelude::XCM_VERSION;
 
-/// Generic extensions for Parachain ChainSpecs.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-pub struct Extensions {
-	/// The relay chain of the Parachain.
-	#[serde(alias = "relayChain", alias = "RelayChain")]
-	pub relay_chain: String,
-	/// The id of the Parachain.
-	#[serde(alias = "paraId", alias = "ParaId")]
-	pub para_id: u32,
-}
-
-impl Extensions {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}
-
 /// Generic chain spec for all polkadot-parachain runtimes
 pub type GenericChainSpec = sc_service::GenericChainSpec<(), Extensions>;
 
diff --git a/cumulus/polkadot-parachain/src/cli.rs b/cumulus/polkadot-parachain/src/cli.rs
index f7d2fd0f0be3..c78af6ca1949 100644
--- a/cumulus/polkadot-parachain/src/cli.rs
+++ b/cumulus/polkadot-parachain/src/cli.rs
@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
 
+use cumulus_client_chain_spec_extension::Extensions;
 use std::path::PathBuf;
 
 /// Sub-commands supported by the collator.
@@ -113,7 +114,7 @@ impl RelayChainCli {
 		para_config: &sc_service::Configuration,
 		relay_chain_args: impl Iterator<Item = &'a String>,
 	) -> Self {
-		let extension = crate::chain_spec::Extensions::try_get(&*para_config.chain_spec);
+		let extension = Extensions::try_get(&*para_config.chain_spec);
 		let chain_id = extension.map(|e| e.relay_chain.clone());
 		let base_path = para_config.base_path.path().join("polkadot");
 		Self {
diff --git a/cumulus/polkadot-parachain/src/command.rs b/cumulus/polkadot-parachain/src/command.rs
index 041187de488f..7dd47037cb02 100644
--- a/cumulus/polkadot-parachain/src/command.rs
+++ b/cumulus/polkadot-parachain/src/command.rs
@@ -644,7 +644,7 @@ pub fn run() -> Result<()> {
 						sc_sysinfo::gather_hwbench(Some(database_path))
 					})).flatten();
 
-				let para_id = chain_spec::Extensions::try_get(&*config.chain_spec)
+				let para_id = cumulus_client_chain_spec_extension::Extensions::try_get(&*config.chain_spec)
 					.map(|e| e.para_id)
 					.ok_or("Could not find parachain extension in chain-spec.")?;
 
diff --git a/cumulus/test/service/Cargo.toml b/cumulus/test/service/Cargo.toml
index 732d884528f8..45cda190fd41 100644
--- a/cumulus/test/service/Cargo.toml
+++ b/cumulus/test/service/Cargo.toml
@@ -88,6 +88,7 @@ cumulus-test-relay-sproof-builder = { path = "../relay-sproof-builder" }
 cumulus-pallet-parachain-system = { path = "../../pallets/parachain-system", default-features = false }
 cumulus-primitives-storage-weight-reclaim = { path = "../../primitives/storage-weight-reclaim" }
 pallet-timestamp = { path = "../../../substrate/frame/timestamp" }
+cumulus-client-chain-spec-extension = { path = "../../client/chain-spec-extension" }
 
 [dev-dependencies]
 futures = "0.3.28"
diff --git a/cumulus/test/service/src/chain_spec.rs b/cumulus/test/service/src/chain_spec.rs
index 4db2513e2b63..ed839faa19c8 100644
--- a/cumulus/test/service/src/chain_spec.rs
+++ b/cumulus/test/service/src/chain_spec.rs
@@ -35,21 +35,6 @@ pub fn get_from_seed<TPublic: Public>(seed: &str) -> <TPublic::Pair as Pair>::Pu
 		.public()
 }
 
-/// The extensions for the [`ChainSpec`].
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-#[serde(deny_unknown_fields)]
-pub struct Extensions {
-	/// The id of the Parachain.
-	pub para_id: u32,
-}
-
-impl Extensions {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}
-
 type AccountPublic = <Signature as Verify>::Signer;
 
 /// Helper function to generate an account ID from seed.
@@ -69,7 +54,10 @@ pub fn get_chain_spec_with_extra_endowed(
 ) -> ChainSpec {
 	ChainSpec::builder(
 		cumulus_test_runtime::WASM_BINARY.expect("WASM binary was not built, please build it!"),
-		Extensions { para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into() },
+		Extensions {
+			para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into(),
+			..Default::default()
+		},
 	)
 	.with_name("Local Testnet")
 	.with_id("local_testnet")
diff --git a/cumulus/test/service/src/main.rs b/cumulus/test/service/src/main.rs
index 90d37173dd59..ac51fb52f962 100644
--- a/cumulus/test/service/src/main.rs
+++ b/cumulus/test/service/src/main.rs
@@ -77,9 +77,10 @@ fn main() -> Result<(), sc_cli::Error> {
 				SubstrateCli::create_configuration(&polkadot_cli, &polkadot_cli, tokio_handle)
 					.map_err(|err| format!("Relay chain argument error: {}", err))?;
 
-			let parachain_id = chain_spec::Extensions::try_get(&*config.chain_spec)
-				.map(|e| e.para_id)
-				.ok_or("Could not find parachain extension in chain-spec.")?;
+			let parachain_id =
+				cumulus_client_chain_spec_extension::Extensions::try_get(&*config.chain_spec)
+					.map(|e| e.para_id)
+					.ok_or("Could not find parachain extension in chain-spec.")?;
 
 			tracing::info!("Parachain id: {:?}", parachain_id);
 			tracing::info!(
diff --git a/substrate/bin/utils/chain-spec-builder/Cargo.toml b/substrate/bin/utils/chain-spec-builder/Cargo.toml
index 0f3cd90d8d67..cbef120f4ec7 100644
--- a/substrate/bin/utils/chain-spec-builder/Cargo.toml
+++ b/substrate/bin/utils/chain-spec-builder/Cargo.toml
@@ -32,3 +32,4 @@ serde = { features = ["derive"], workspace = true, default-features = true }
 sp-runtime = { path = "../../../primitives/runtime" }
 sp-core = { path = "../../../primitives/core" }
 sc-service = { path = "../../../client/service", default-features = false }
+cumulus-client-chain-spec-extension = { path = "../../../../cumulus/client/chain-spec-extension" }
diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index ce5ca70eb3da..3e8310bfbefe 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -18,9 +18,10 @@
 
 use chain_spec_builder::{
 	generate_chain_spec_for_runtime, AddCodeSubstituteCmd, ChainSpecBuilder, ChainSpecBuilderCmd,
-	ConvertToRawCmd, DisplayPresetCmd, Extensions, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
+	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
 };
 use clap::Parser;
+use cumulus_client_chain_spec_extension::Extensions;
 use sc_chain_spec::{
 	set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec, GenericChainSpec,
 	GenesisConfigBuilderRuntimeCaller,
@@ -28,6 +29,8 @@ use sc_chain_spec::{
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
 
+type ChainSpec = GenericChainSpec<(), Extensions>;
+
 //avoid error message escaping
 fn main() {
 	match inner_main() {
@@ -51,8 +54,7 @@ fn inner_main() -> Result<(), String> {
 			ref input_chain_spec,
 			ref runtime_wasm_path,
 		}) => {
-			let chain_spec =
-				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec = ChainSpec::from_json_file(input_chain_spec.clone())?;
 
 			let mut chain_spec_json =
 				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(false)?)
@@ -72,8 +74,7 @@ fn inner_main() -> Result<(), String> {
 			ref runtime_wasm_path,
 			block_height,
 		}) => {
-			let chain_spec =
-				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec = ChainSpec::from_json_file(input_chain_spec.clone())?;
 
 			let mut chain_spec_json =
 				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(false)?)
@@ -90,8 +91,7 @@ fn inner_main() -> Result<(), String> {
 			fs::write(chain_spec_path, chain_spec_json).map_err(|err| err.to_string())?;
 		},
 		ChainSpecBuilderCmd::ConvertToRaw(ConvertToRawCmd { ref input_chain_spec }) => {
-			let chain_spec =
-				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec = ChainSpec::from_json_file(input_chain_spec.clone())?;
 
 			let chain_spec_json =
 				serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(true)?)
@@ -102,8 +102,7 @@ fn inner_main() -> Result<(), String> {
 			fs::write(chain_spec_path, chain_spec_json).map_err(|err| err.to_string())?;
 		},
 		ChainSpecBuilderCmd::Verify(VerifyCmd { ref input_chain_spec }) => {
-			let chain_spec =
-				GenericChainSpec::<(), Extensions>::from_json_file(input_chain_spec.clone())?;
+			let chain_spec = ChainSpec::from_json_file(input_chain_spec.clone())?;
 			let _ = serde_json::from_str::<serde_json::Value>(&chain_spec.as_json(true)?)
 				.map_err(|e| format!("Conversion to json failed: {e}"))?;
 		},
diff --git a/substrate/bin/utils/chain-spec-builder/src/lib.rs b/substrate/bin/utils/chain-spec-builder/src/lib.rs
index 78a8f21a33e9..2a681b7ae9e1 100644
--- a/substrate/bin/utils/chain-spec-builder/src/lib.rs
+++ b/substrate/bin/utils/chain-spec-builder/src/lib.rs
@@ -121,9 +121,8 @@ use std::{fs, path::PathBuf};
 
 use clap::{Parser, Subcommand};
 use sc_chain_spec::{
-	ChainSpecExtension, ChainSpecGroup, GenericChainSpec, GenesisConfigBuilderRuntimeCaller,
+	GenericChainSpec, GenesisConfigBuilderRuntimeCaller,
 };
-use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
 /// A utility to easily create a chain spec definition.
@@ -258,29 +257,6 @@ pub struct DisplayPresetCmd {
 	pub preset_name: Option<String>,
 }
 
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-pub struct Extensions {
-	/// The relay chain of the Parachain.
-	#[serde(alias = "relayChain", alias = "RelayChain")]
-	pub relay_chain: String,
-	/// The id of the Parachain.
-	#[serde(alias = "paraId", alias = "ParaId")]
-	pub para_id: u32,
-}
-
-impl Extensions {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}
-
-impl sp_runtime::BuildStorage for Extensions {
-	/// Assimilate the storage for this module into pre-existing overlays.
-	fn assimilate_storage(&self, storage: &mut sp_core::storage::Storage) -> Result<(), String> {
-		unimplemented!();
-	}
-}
 /// Verifies the provided input chain spec.
 ///
 /// Silently checks if given input chain spec can be converted to raw. It allows to check if all
diff --git a/templates/parachain/node/Cargo.toml b/templates/parachain/node/Cargo.toml
index 6f7150829829..ac99132fd123 100644
--- a/templates/parachain/node/Cargo.toml
+++ b/templates/parachain/node/Cargo.toml
@@ -20,7 +20,6 @@ workspace = true
 clap = { version = "4.5.3", features = ["derive"] }
 log = { workspace = true, default-features = true }
 codec = { package = "parity-scale-codec", version = "3.6.12" }
-serde = { features = ["derive"], workspace = true, default-features = true }
 jsonrpsee = { version = "0.22", features = ["server"] }
 futures = "0.3.28"
 serde_json = { workspace = true, default-features = true }
@@ -77,6 +76,7 @@ cumulus-primitives-core = { path = "../../../cumulus/primitives/core" }
 cumulus-primitives-parachain-inherent = { path = "../../../cumulus/primitives/parachain-inherent" }
 cumulus-relay-chain-interface = { path = "../../../cumulus/client/relay-chain-interface" }
 color-print = "0.3.4"
+cumulus-client-chain-spec-extension = { path = "../../../cumulus/client/chain-spec-extension" }
 
 [build-dependencies]
 substrate-build-script-utils = { path = "../../../substrate/utils/build-script-utils" }
diff --git a/templates/parachain/node/src/chain_spec.rs b/templates/parachain/node/src/chain_spec.rs
index 51710f1199c3..4f68323170d8 100644
--- a/templates/parachain/node/src/chain_spec.rs
+++ b/templates/parachain/node/src/chain_spec.rs
@@ -1,9 +1,8 @@
+use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_primitives_core::ParaId;
 use parachain_template_runtime as runtime;
 use runtime::{AccountId, AuraId, Signature, EXISTENTIAL_DEPOSIT};
-use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
 use sc_service::ChainType;
-use serde::{Deserialize, Serialize};
 use sp_core::{sr25519, Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -20,24 +19,6 @@ pub fn get_from_seed<TPublic: Public>(seed: &str) -> <TPublic::Pair as Pair>::Pu
 		.public()
 }
 
-/// The extensions for the [`ChainSpec`].
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-pub struct Extensions {
-	/// The relay chain of the Parachain.
-	#[serde(alias = "relayChain", alias = "RelayChain")]
-	pub relay_chain: String,
-	/// The id of the Parachain.
-	#[serde(alias = "paraId", alias = "ParaId")]
-	pub para_id: u32,
-}
-
-impl Extensions {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}
-
 type AccountPublic = <Signature as Verify>::Signer;
 
 /// Generate collator keys from seed.
diff --git a/templates/parachain/node/src/cli.rs b/templates/parachain/node/src/cli.rs
index cffbfbc1db23..ec77ce94fa59 100644
--- a/templates/parachain/node/src/cli.rs
+++ b/templates/parachain/node/src/cli.rs
@@ -1,5 +1,7 @@
 use std::path::PathBuf;
 
+use cumulus_client_chain_spec_extension::Extensions;
+
 /// Sub-commands supported by the collator.
 #[derive(Debug, clap::Subcommand)]
 pub enum Subcommand {
@@ -98,7 +100,7 @@ impl RelayChainCli {
 		para_config: &sc_service::Configuration,
 		relay_chain_args: impl Iterator<Item = &'a String>,
 	) -> Self {
-		let extension = crate::chain_spec::Extensions::try_get(&*para_config.chain_spec);
+		let extension = Extensions::try_get(&*para_config.chain_spec);
 		let chain_id = extension.map(|e| e.relay_chain.clone());
 		let base_path = para_config.base_path.path().join("polkadot");
 		Self {
diff --git a/templates/parachain/node/src/command.rs b/templates/parachain/node/src/command.rs
index 56ae022cad2b..65f2e813f8f6 100644
--- a/templates/parachain/node/src/command.rs
+++ b/templates/parachain/node/src/command.rs
@@ -1,5 +1,6 @@
 use std::net::SocketAddr;
 
+use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_client_service::storage_proof_size::HostFunctions as ReclaimHostFunctions;
 use cumulus_primitives_core::ParaId;
 use frame_benchmarking_cli::{BenchmarkCmd, SUBSTRATE_REFERENCE_HARDWARE};
@@ -228,7 +229,7 @@ pub fn run() -> Result<()> {
 					}))
 					.flatten();
 
-				let para_id = chain_spec::Extensions::try_get(&*config.chain_spec)
+				let para_id = Extensions::try_get(&*config.chain_spec)
 					.map(|e| e.para_id)
 					.ok_or("Could not find parachain ID in chain-spec.")?;
 

From ae2d7c132d9687a30f72c236e3e621887c3c310d Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Mon, 3 Jun 2024 15:55:16 +0200
Subject: [PATCH 03/10] Fix build

---
 cumulus/test/service/src/chain_spec.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/cumulus/test/service/src/chain_spec.rs b/cumulus/test/service/src/chain_spec.rs
index 1ae034c371d6..3169735fd49a 100644
--- a/cumulus/test/service/src/chain_spec.rs
+++ b/cumulus/test/service/src/chain_spec.rs
@@ -16,6 +16,7 @@
 
 #![allow(missing_docs)]
 
+use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_primitives_core::ParaId;
 use cumulus_test_runtime::{AccountId, Signature};
 use parachains_common::AuraId;
@@ -56,7 +57,7 @@ pub fn get_chain_spec_with_extra_endowed(
 		cumulus_test_runtime::WASM_BINARY.expect("WASM binary was not built, please build it!"),
 		Extensions {
 			para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into(),
-			..Default::default()
+			relay_chain: "rococo-local",
 		},
 	)
 	.with_name("Local Testnet")

From fb588eaeb35a0e82376e91d18225a7833587c06b Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Mon, 3 Jun 2024 17:19:02 +0200
Subject: [PATCH 04/10] More fixes

---
 Cargo.lock                                         | 2 +-
 cumulus/polkadot-parachain/Cargo.toml              | 1 +
 cumulus/test/service/Cargo.toml                    | 1 -
 cumulus/test/service/src/chain_spec.rs             | 4 +---
 cumulus/test/service/src/main.rs                   | 2 +-
 substrate/bin/utils/chain-spec-builder/bin/main.rs | 2 +-
 6 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index b4af722adf5d..1e0246229e67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4433,7 +4433,6 @@ dependencies = [
  "sc-tracing",
  "sc-transaction-pool",
  "sc-transaction-pool-api",
- "serde",
  "serde_json",
  "sp-api",
  "sp-arithmetic",
@@ -13617,6 +13616,7 @@ dependencies = [
  "sc-transaction-pool",
  "sc-transaction-pool-api",
  "seedling-runtime",
+ "serde",
  "serde_json",
  "shell-runtime",
  "sp-api",
diff --git a/cumulus/polkadot-parachain/Cargo.toml b/cumulus/polkadot-parachain/Cargo.toml
index de898fef266b..704e856eec90 100644
--- a/cumulus/polkadot-parachain/Cargo.toml
+++ b/cumulus/polkadot-parachain/Cargo.toml
@@ -21,6 +21,7 @@ codec = { package = "parity-scale-codec", version = "3.6.12" }
 futures = "0.3.28"
 hex-literal = "0.4.1"
 log = { workspace = true, default-features = true }
+serde = { features = ["derive"], workspace = true, default-features = true }
 serde_json = { workspace = true, default-features = true }
 
 # Local
diff --git a/cumulus/test/service/Cargo.toml b/cumulus/test/service/Cargo.toml
index 45cda190fd41..dbfca72941bf 100644
--- a/cumulus/test/service/Cargo.toml
+++ b/cumulus/test/service/Cargo.toml
@@ -19,7 +19,6 @@ codec = { package = "parity-scale-codec", version = "3.6.12" }
 criterion = { version = "0.5.1", features = ["async_tokio"] }
 jsonrpsee = { version = "0.22", features = ["server"] }
 rand = "0.8.5"
-serde = { features = ["derive"], workspace = true, default-features = true }
 serde_json = { workspace = true, default-features = true }
 tokio = { version = "1.32.0", features = ["macros"] }
 tracing = "0.1.37"
diff --git a/cumulus/test/service/src/chain_spec.rs b/cumulus/test/service/src/chain_spec.rs
index 3169735fd49a..456427886162 100644
--- a/cumulus/test/service/src/chain_spec.rs
+++ b/cumulus/test/service/src/chain_spec.rs
@@ -20,9 +20,7 @@ use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_primitives_core::ParaId;
 use cumulus_test_runtime::{AccountId, Signature};
 use parachains_common::AuraId;
-use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
 use sc_service::ChainType;
-use serde::{Deserialize, Serialize};
 use sp_core::{sr25519, Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -57,7 +55,7 @@ pub fn get_chain_spec_with_extra_endowed(
 		cumulus_test_runtime::WASM_BINARY.expect("WASM binary was not built, please build it!"),
 		Extensions {
 			para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into(),
-			relay_chain: "rococo-local",
+			relay_chain: "rococo-local".to_string(),
 		},
 	)
 	.with_name("Local Testnet")
diff --git a/cumulus/test/service/src/main.rs b/cumulus/test/service/src/main.rs
index ac51fb52f962..67f0e9354439 100644
--- a/cumulus/test/service/src/main.rs
+++ b/cumulus/test/service/src/main.rs
@@ -20,7 +20,7 @@ use std::sync::Arc;
 
 use cli::{RelayChainCli, Subcommand, TestCollatorCli};
 use cumulus_primitives_core::relay_chain::CollatorPair;
-use cumulus_test_service::{chain_spec, new_partial, AnnounceBlockFn};
+use cumulus_test_service::{new_partial, AnnounceBlockFn};
 use sc_cli::{CliConfiguration, SubstrateCli};
 use sp_core::Pair;
 
diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index 3e8310bfbefe..aba2456793a7 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -29,7 +29,7 @@ use sc_chain_spec::{
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
 
-type ChainSpec = GenericChainSpec<(), Extensions>;
+type ChainSpec = GenericChainSpec<Extensions, ()>;
 
 //avoid error message escaping
 fn main() {

From cc978aacf91c4a9f147343afc73bde1fc01934b1 Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Mon, 3 Jun 2024 17:46:55 +0200
Subject: [PATCH 05/10] Make relay_chain_optional

---
 .../bin/utils/chain-spec-builder/bin/main.rs  |  7 +++---
 .../bin/utils/chain-spec-builder/src/lib.rs   | 24 ++++++++++++++++++-
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index aba2456793a7..73e7c968bb40 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -18,18 +18,17 @@
 
 use chain_spec_builder::{
 	generate_chain_spec_for_runtime, AddCodeSubstituteCmd, ChainSpecBuilder, ChainSpecBuilderCmd,
-	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
+	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, OptionalParaFieldsExtension, UpdateCodeCmd,
+	VerifyCmd,
 };
 use clap::Parser;
-use cumulus_client_chain_spec_extension::Extensions;
 use sc_chain_spec::{
 	set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec, GenericChainSpec,
 	GenesisConfigBuilderRuntimeCaller,
 };
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
-
-type ChainSpec = GenericChainSpec<Extensions, ()>;
+type ChainSpec = GenericChainSpec<OptionalParaFieldsExtension, ()>;
 
 //avoid error message escaping
 fn main() {
diff --git a/substrate/bin/utils/chain-spec-builder/src/lib.rs b/substrate/bin/utils/chain-spec-builder/src/lib.rs
index aa23ec6d4231..1cbb466321c3 100644
--- a/substrate/bin/utils/chain-spec-builder/src/lib.rs
+++ b/substrate/bin/utils/chain-spec-builder/src/lib.rs
@@ -120,7 +120,11 @@
 use std::{fs, path::PathBuf};
 
 use clap::{Parser, Subcommand};
-use sc_chain_spec::{ChainType, GenericChainSpec, GenesisConfigBuilderRuntimeCaller};
+use sc_chain_spec::{
+	ChainSpecExtension, ChainSpecGroup, ChainType, GenericChainSpec,
+	GenesisConfigBuilderRuntimeCaller,
+};
+use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
 /// A utility to easily create a chain spec definition.
@@ -325,3 +329,21 @@ pub fn generate_chain_spec_for_runtime(cmd: &CreateCmd) -> Result<String, String
 		(false, false) => chain_spec.as_json(false),
 	}
 }
+
+/// Chain-spec extension that provides access to optional `relay_chain` and `para_id` fields.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+pub struct OptionalParaFieldsExtension {
+	/// The relay chain of the Parachain.
+	#[serde(alias = "relayChain", alias = "RelayChain")]
+	pub relay_chain: Option<String>,
+	/// The id of the Parachain.
+	#[serde(alias = "paraId", alias = "ParaId")]
+	pub para_id: Option<u32>,
+}
+
+impl OptionalParaFieldsExtension {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn sc_chain_spec::ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}

From b50a2c5e8355954a2cab0e234fe63fdb80cfdfbf Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Tue, 4 Jun 2024 09:31:01 +0200
Subject: [PATCH 06/10] Refer to external extension but make optional

---
 Cargo.lock                                    |  1 -
 .../bin/utils/chain-spec-builder/Cargo.toml   |  1 -
 .../bin/utils/chain-spec-builder/bin/main.rs  |  7 +++---
 .../bin/utils/chain-spec-builder/src/lib.rs   | 24 +------------------
 4 files changed, 5 insertions(+), 28 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 1e0246229e67..abdbc771ceda 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -20560,7 +20560,6 @@ dependencies = [
  "log",
  "sc-chain-spec",
  "sc-service",
- "serde",
  "serde_json",
  "sp-core",
  "sp-runtime",
diff --git a/substrate/bin/utils/chain-spec-builder/Cargo.toml b/substrate/bin/utils/chain-spec-builder/Cargo.toml
index a213d980a65b..2e0f5a149283 100644
--- a/substrate/bin/utils/chain-spec-builder/Cargo.toml
+++ b/substrate/bin/utils/chain-spec-builder/Cargo.toml
@@ -29,7 +29,6 @@ log = { workspace = true, default-features = true }
 sc-chain-spec = { path = "../../../client/chain-spec", features = ["clap"] }
 serde_json = { workspace = true, default-features = true }
 sp-tracing = { path = "../../../primitives/tracing" }
-serde = { features = ["derive"], workspace = true, default-features = true }
 sp-runtime = { path = "../../../primitives/runtime" }
 sp-core = { path = "../../../primitives/core" }
 sc-service = { path = "../../../client/service", default-features = false }
diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index 73e7c968bb40..dd76517f4b12 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -18,17 +18,18 @@
 
 use chain_spec_builder::{
 	generate_chain_spec_for_runtime, AddCodeSubstituteCmd, ChainSpecBuilder, ChainSpecBuilderCmd,
-	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, OptionalParaFieldsExtension, UpdateCodeCmd,
-	VerifyCmd,
+	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
 };
 use clap::Parser;
+use cumulus_client_chain_spec_extension::Extensions;
 use sc_chain_spec::{
 	set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec, GenericChainSpec,
 	GenesisConfigBuilderRuntimeCaller,
 };
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
-type ChainSpec = GenericChainSpec<OptionalParaFieldsExtension, ()>;
+
+type ChainSpec = GenericChainSpec<Option<Extensions>, ()>;
 
 //avoid error message escaping
 fn main() {
diff --git a/substrate/bin/utils/chain-spec-builder/src/lib.rs b/substrate/bin/utils/chain-spec-builder/src/lib.rs
index 1cbb466321c3..aa23ec6d4231 100644
--- a/substrate/bin/utils/chain-spec-builder/src/lib.rs
+++ b/substrate/bin/utils/chain-spec-builder/src/lib.rs
@@ -120,11 +120,7 @@
 use std::{fs, path::PathBuf};
 
 use clap::{Parser, Subcommand};
-use sc_chain_spec::{
-	ChainSpecExtension, ChainSpecGroup, ChainType, GenericChainSpec,
-	GenesisConfigBuilderRuntimeCaller,
-};
-use serde::{Deserialize, Serialize};
+use sc_chain_spec::{ChainType, GenericChainSpec, GenesisConfigBuilderRuntimeCaller};
 use serde_json::Value;
 
 /// A utility to easily create a chain spec definition.
@@ -329,21 +325,3 @@ pub fn generate_chain_spec_for_runtime(cmd: &CreateCmd) -> Result<String, String
 		(false, false) => chain_spec.as_json(false),
 	}
 }
-
-/// Chain-spec extension that provides access to optional `relay_chain` and `para_id` fields.
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-pub struct OptionalParaFieldsExtension {
-	/// The relay chain of the Parachain.
-	#[serde(alias = "relayChain", alias = "RelayChain")]
-	pub relay_chain: Option<String>,
-	/// The id of the Parachain.
-	#[serde(alias = "paraId", alias = "ParaId")]
-	pub para_id: Option<u32>,
-}
-
-impl OptionalParaFieldsExtension {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn sc_chain_spec::ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}

From 4259adbc9548a17968533db3258bc2fc572e53ee Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Tue, 4 Jun 2024 14:50:14 +0200
Subject: [PATCH 07/10] Add prdoc, fix toml format

---
 Cargo.toml          |  2 +-
 prdoc/pr_4685.prdoc | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 prdoc/pr_4685.prdoc

diff --git a/Cargo.toml b/Cargo.toml
index 0696580d8960..72dcdf5bdb59 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -61,13 +61,13 @@ members = [
 	"bridges/snowbridge/primitives/router",
 	"bridges/snowbridge/runtime/runtime-common",
 	"bridges/snowbridge/runtime/test-common",
+	"cumulus/client/chain-spec-extension",
 	"cumulus/client/cli",
 	"cumulus/client/collator",
 	"cumulus/client/consensus/aura",
 	"cumulus/client/consensus/common",
 	"cumulus/client/consensus/proposer",
 	"cumulus/client/consensus/relay-chain",
-	"cumulus/client/chain-spec-extension",
 	"cumulus/client/network",
 	"cumulus/client/parachain-inherent",
 	"cumulus/client/pov-recovery",
diff --git a/prdoc/pr_4685.prdoc b/prdoc/pr_4685.prdoc
new file mode 100644
index 000000000000..36b2b33c23ca
--- /dev/null
+++ b/prdoc/pr_4685.prdoc
@@ -0,0 +1,16 @@
+# 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: Chain-spec-builder supports parachain chain-specs and `codeSubstitutes`.
+
+doc:
+  - audience: Node Operator
+    description: |
+      Chain-spec-builder now supports parachain chain-specs. Parachain chain-specs have the `relay_chain` and `para_id` fields.
+      Before this change, the fields would get silently removed when using the chain-spec-builder.
+      In addition, a new subcommand `add-code-substitute` is available. It allows users to provide a runtime that should be used from a given
+      block onwards.
+
+crates:
+  - name: staging-chain-spec-builder
+    bump: major

From 79155a9180bcb629b13f4b3d7271da1acc5ce1e0 Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Tue, 4 Jun 2024 15:33:35 +0200
Subject: [PATCH 08/10] Change bump to minor

---
 prdoc/pr_4685.prdoc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/prdoc/pr_4685.prdoc b/prdoc/pr_4685.prdoc
index 36b2b33c23ca..a9d3bf49a277 100644
--- a/prdoc/pr_4685.prdoc
+++ b/prdoc/pr_4685.prdoc
@@ -13,4 +13,4 @@ doc:
 
 crates:
   - name: staging-chain-spec-builder
-    bump: major
+    bump: minor

From 49ddf11eb3b38cd8975f9af961618afa0e1fe4eb Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Tue, 25 Jun 2024 13:44:16 +0200
Subject: [PATCH 09/10] Revert extension related changeS

---
 Cargo.lock                                    | 17 +--------
 Cargo.toml                                    |  2 -
 .../client/chain-spec-extension/Cargo.toml    | 14 -------
 .../client/chain-spec-extension/src/lib.rs    | 38 -------------------
 cumulus/polkadot-parachain/Cargo.toml         |  2 -
 .../polkadot-parachain/src/chain_spec/mod.rs  | 21 +++++++++-
 cumulus/polkadot-parachain/src/cli.rs         |  1 -
 cumulus/polkadot-parachain/src/command.rs     |  2 +-
 cumulus/test/service/src/chain_spec.rs        | 23 ++++++++---
 cumulus/test/service/src/main.rs              |  9 ++---
 .../bin/utils/chain-spec-builder/Cargo.toml   |  4 --
 .../bin/utils/chain-spec-builder/bin/main.rs  |  3 +-
 templates/parachain/node/Cargo.toml           |  1 -
 templates/parachain/node/src/chain_spec.rs    | 21 +++++++++-
 templates/parachain/node/src/cli.rs           |  4 +-
 templates/parachain/node/src/command.rs       |  3 +-
 16 files changed, 68 insertions(+), 97 deletions(-)
 delete mode 100644 cumulus/client/chain-spec-extension/Cargo.toml
 delete mode 100644 cumulus/client/chain-spec-extension/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index 98652e630704..22564aa9cae3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3618,14 +3618,6 @@ dependencies = [
  "cipher 0.4.4",
 ]
 
-[[package]]
-name = "cumulus-client-chain-spec-extension"
-version = "0.1.0"
-dependencies = [
- "sc-chain-spec",
- "serde",
-]
-
 [[package]]
 name = "cumulus-client-cli"
 version = "0.7.0"
@@ -4425,7 +4417,6 @@ dependencies = [
  "async-trait",
  "clap 4.5.3",
  "criterion",
- "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -4477,6 +4468,7 @@ dependencies = [
  "sc-tracing",
  "sc-transaction-pool",
  "sc-transaction-pool-api",
+ "serde",
  "serde_json",
  "sp-api",
  "sp-arithmetic",
@@ -11810,7 +11802,6 @@ version = "0.0.0"
 dependencies = [
  "clap 4.5.3",
  "color-print",
- "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -11847,6 +11838,7 @@ dependencies = [
  "sc-tracing",
  "sc-transaction-pool",
  "sc-transaction-pool-api",
+ "serde",
  "serde_json",
  "sp-api",
  "sp-block-builder",
@@ -13653,7 +13645,6 @@ dependencies = [
  "contracts-rococo-runtime",
  "coretime-rococo-runtime",
  "coretime-westend-runtime",
- "cumulus-client-chain-spec-extension",
  "cumulus-client-cli",
  "cumulus-client-collator",
  "cumulus-client-consensus-aura",
@@ -20676,13 +20667,9 @@ name = "staging-chain-spec-builder"
 version = "1.6.1"
 dependencies = [
  "clap 4.5.3",
- "cumulus-client-chain-spec-extension",
  "log",
  "sc-chain-spec",
- "sc-service",
  "serde_json",
- "sp-core",
- "sp-runtime",
  "sp-tracing 16.0.0",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index a76d4eee7c7c..60459500a890 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -61,7 +61,6 @@ members = [
 	"bridges/snowbridge/primitives/router",
 	"bridges/snowbridge/runtime/runtime-common",
 	"bridges/snowbridge/runtime/test-common",
-	"cumulus/client/chain-spec-extension",
 	"cumulus/client/cli",
 	"cumulus/client/collator",
 	"cumulus/client/consensus/aura",
@@ -680,7 +679,6 @@ cumulus-client-consensus-proposer = { path = "cumulus/client/consensus/proposer"
 cumulus-client-consensus-relay-chain = { path = "cumulus/client/consensus/relay-chain", default-features = false }
 cumulus-client-network = { path = "cumulus/client/network", default-features = false }
 cumulus-client-parachain-inherent = { path = "cumulus/client/parachain-inherent", default-features = false }
-cumulus-client-chain-spec-extension = { path = "cumulus/client/chain-spec-extension", default-features = false }
 cumulus-client-pov-recovery = { path = "cumulus/client/pov-recovery", default-features = false }
 cumulus-client-service = { path = "cumulus/client/service", default-features = false }
 cumulus-pallet-aura-ext = { path = "cumulus/pallets/aura-ext", default-features = false }
diff --git a/cumulus/client/chain-spec-extension/Cargo.toml b/cumulus/client/chain-spec-extension/Cargo.toml
deleted file mode 100644
index 7d27f944afed..000000000000
--- a/cumulus/client/chain-spec-extension/Cargo.toml
+++ /dev/null
@@ -1,14 +0,0 @@
-[package]
-name = "cumulus-client-chain-spec-extension"
-version = "0.1.0"
-authors.workspace = true
-edition.workspace = true
-description = "Parachain chain-spec extension."
-license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
-
-[lints]
-workspace = true
-
-[dependencies]
-sc-chain-spec = { path = "../../../substrate/client/chain-spec" }
-serde = { features = ["derive"], workspace = true, default-features = true }
diff --git a/cumulus/client/chain-spec-extension/src/lib.rs b/cumulus/client/chain-spec-extension/src/lib.rs
deleted file mode 100644
index 495e084fd9cb..000000000000
--- a/cumulus/client/chain-spec-extension/src/lib.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright (C) Parity Technologies (UK) Ltd.
-// This file is part of Cumulus.
-
-// Cumulus is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Cumulus is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
-
-//! Chain spec extension for parachains.
-
-use sc_chain_spec::{ChainSpec, ChainSpecExtension, ChainSpecGroup};
-use serde::{Deserialize, Serialize};
-
-/// The extensions for the [`ChainSpec`].
-#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
-pub struct Extensions {
-	/// The relay chain of the Parachain.
-	#[serde(alias = "relayChain", alias = "RelayChain")]
-	pub relay_chain: String,
-	/// The id of the Parachain.
-	#[serde(alias = "paraId", alias = "ParaId")]
-	pub para_id: u32,
-}
-
-impl Extensions {
-	/// Try to get the extension from the given `ChainSpec`.
-	pub fn try_get(chain_spec: &dyn ChainSpec) -> Option<&Self> {
-		sc_chain_spec::get_extension(chain_spec.extensions())
-	}
-}
diff --git a/cumulus/polkadot-parachain/Cargo.toml b/cumulus/polkadot-parachain/Cargo.toml
index 37b0cca9b329..d12eaa5c0d49 100644
--- a/cumulus/polkadot-parachain/Cargo.toml
+++ b/cumulus/polkadot-parachain/Cargo.toml
@@ -112,8 +112,6 @@ cumulus-client-service = { workspace = true, default-features = true }
 cumulus-primitives-aura = { workspace = true, default-features = true }
 cumulus-primitives-core = { workspace = true, default-features = true }
 cumulus-relay-chain-interface = { workspace = true, default-features = true }
-cumulus-client-chain-spec-extension = { workspace = true, default-features = true }
-
 
 [build-dependencies]
 substrate-build-script-utils = { workspace = true, default-features = true }
diff --git a/cumulus/polkadot-parachain/src/chain_spec/mod.rs b/cumulus/polkadot-parachain/src/chain_spec/mod.rs
index ae3d5b248caa..19047b073b05 100644
--- a/cumulus/polkadot-parachain/src/chain_spec/mod.rs
+++ b/cumulus/polkadot-parachain/src/chain_spec/mod.rs
@@ -14,8 +14,9 @@
 // You should have received a copy of the GNU General Public License
 // along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
 
-use cumulus_client_chain_spec_extension::Extensions;
 use parachains_common::{AccountId, Signature};
+use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
+use serde::{Deserialize, Serialize};
 use sp_core::{Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -34,6 +35,24 @@ pub mod shell;
 /// The default XCM version to set in genesis config.
 const SAFE_XCM_VERSION: u32 = xcm::prelude::XCM_VERSION;
 
+/// Generic extensions for Parachain ChainSpecs.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+pub struct Extensions {
+	/// The relay chain of the Parachain.
+	#[serde(alias = "relayChain", alias = "RelayChain")]
+	pub relay_chain: String,
+	/// The id of the Parachain.
+	#[serde(alias = "paraId", alias = "ParaId")]
+	pub para_id: u32,
+}
+
+impl Extensions {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}
+
 /// Generic chain spec for all polkadot-parachain runtimes
 pub type GenericChainSpec = sc_service::GenericChainSpec<Extensions>;
 
diff --git a/cumulus/polkadot-parachain/src/cli.rs b/cumulus/polkadot-parachain/src/cli.rs
index 117c75ca44f0..fa4b4da1ba9c 100644
--- a/cumulus/polkadot-parachain/src/cli.rs
+++ b/cumulus/polkadot-parachain/src/cli.rs
@@ -15,7 +15,6 @@
 // along with Cumulus.  If not, see <http://www.gnu.org/licenses/>.
 
 use clap::{CommandFactory, FromArgMatches};
-use cumulus_client_chain_spec_extension::Extensions;
 use std::path::PathBuf;
 
 /// Sub-commands supported by the collator.
diff --git a/cumulus/polkadot-parachain/src/command.rs b/cumulus/polkadot-parachain/src/command.rs
index 8dcfb0e98fa5..6b3f4b4cd0a7 100644
--- a/cumulus/polkadot-parachain/src/command.rs
+++ b/cumulus/polkadot-parachain/src/command.rs
@@ -641,7 +641,7 @@ pub fn run() -> Result<()> {
 						sc_sysinfo::gather_hwbench(Some(database_path))
 					})).flatten();
 
-				let para_id = cumulus_client_chain_spec_extension::Extensions::try_get(&*config.chain_spec)
+				let para_id = chain_spec::Extensions::try_get(&*config.chain_spec)
 					.map(|e| e.para_id)
 					.ok_or("Could not find parachain extension in chain-spec.")?;
 
diff --git a/cumulus/test/service/src/chain_spec.rs b/cumulus/test/service/src/chain_spec.rs
index fd289f8591ab..174d478f2575 100644
--- a/cumulus/test/service/src/chain_spec.rs
+++ b/cumulus/test/service/src/chain_spec.rs
@@ -16,11 +16,12 @@
 
 #![allow(missing_docs)]
 
-use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_primitives_core::ParaId;
 use cumulus_test_runtime::{AccountId, Signature};
 use parachains_common::AuraId;
+use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
 use sc_service::ChainType;
+use serde::{Deserialize, Serialize};
 use sp_core::{sr25519, Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -34,6 +35,21 @@ pub fn get_from_seed<TPublic: Public>(seed: &str) -> <TPublic::Pair as Pair>::Pu
 		.public()
 }
 
+/// The extensions for the [`ChainSpec`].
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+#[serde(deny_unknown_fields)]
+pub struct Extensions {
+	/// The id of the Parachain.
+	pub para_id: u32,
+}
+
+impl Extensions {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}
+
 type AccountPublic = <Signature as Verify>::Signer;
 
 /// Helper function to generate an account ID from seed.
@@ -53,10 +69,7 @@ pub fn get_chain_spec_with_extra_endowed(
 ) -> ChainSpec {
 	ChainSpec::builder(
 		cumulus_test_runtime::WASM_BINARY.expect("WASM binary was not built, please build it!"),
-		Extensions {
-			para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into(),
-			relay_chain: "rococo-local".to_string(),
-		},
+		Extensions { para_id: id.unwrap_or(cumulus_test_runtime::PARACHAIN_ID.into()).into() },
 	)
 	.with_name("Local Testnet")
 	.with_id("local_testnet")
diff --git a/cumulus/test/service/src/main.rs b/cumulus/test/service/src/main.rs
index 67f0e9354439..90d37173dd59 100644
--- a/cumulus/test/service/src/main.rs
+++ b/cumulus/test/service/src/main.rs
@@ -20,7 +20,7 @@ use std::sync::Arc;
 
 use cli::{RelayChainCli, Subcommand, TestCollatorCli};
 use cumulus_primitives_core::relay_chain::CollatorPair;
-use cumulus_test_service::{new_partial, AnnounceBlockFn};
+use cumulus_test_service::{chain_spec, new_partial, AnnounceBlockFn};
 use sc_cli::{CliConfiguration, SubstrateCli};
 use sp_core::Pair;
 
@@ -77,10 +77,9 @@ fn main() -> Result<(), sc_cli::Error> {
 				SubstrateCli::create_configuration(&polkadot_cli, &polkadot_cli, tokio_handle)
 					.map_err(|err| format!("Relay chain argument error: {}", err))?;
 
-			let parachain_id =
-				cumulus_client_chain_spec_extension::Extensions::try_get(&*config.chain_spec)
-					.map(|e| e.para_id)
-					.ok_or("Could not find parachain extension in chain-spec.")?;
+			let parachain_id = chain_spec::Extensions::try_get(&*config.chain_spec)
+				.map(|e| e.para_id)
+				.ok_or("Could not find parachain extension in chain-spec.")?;
 
 			tracing::info!("Parachain id: {:?}", parachain_id);
 			tracing::info!(
diff --git a/substrate/bin/utils/chain-spec-builder/Cargo.toml b/substrate/bin/utils/chain-spec-builder/Cargo.toml
index bbb8e858d221..083f2191f3c5 100644
--- a/substrate/bin/utils/chain-spec-builder/Cargo.toml
+++ b/substrate/bin/utils/chain-spec-builder/Cargo.toml
@@ -29,7 +29,3 @@ log = { workspace = true, default-features = true }
 sc-chain-spec = { features = ["clap"], workspace = true, default-features = true }
 serde_json = { workspace = true, default-features = true }
 sp-tracing = { workspace = true, default-features = true }
-sp-runtime = { workspace = true, default-features = true }
-sp-core = { workspace = true, default-features = true }
-sc-service = { workspace = true, default-features = true }
-cumulus-client-chain-spec-extension = { workspace = true, default-features = true }
\ No newline at end of file
diff --git a/substrate/bin/utils/chain-spec-builder/bin/main.rs b/substrate/bin/utils/chain-spec-builder/bin/main.rs
index 01eb46e5e19e..39fa054b4806 100644
--- a/substrate/bin/utils/chain-spec-builder/bin/main.rs
+++ b/substrate/bin/utils/chain-spec-builder/bin/main.rs
@@ -21,7 +21,6 @@ use chain_spec_builder::{
 	ConvertToRawCmd, DisplayPresetCmd, ListPresetsCmd, UpdateCodeCmd, VerifyCmd,
 };
 use clap::Parser;
-use cumulus_client_chain_spec_extension::Extensions;
 use sc_chain_spec::{
 	set_code_substitute_in_json_chain_spec, update_code_in_json_chain_spec, GenericChainSpec,
 	GenesisConfigBuilderRuntimeCaller,
@@ -29,7 +28,7 @@ use sc_chain_spec::{
 use staging_chain_spec_builder as chain_spec_builder;
 use std::fs;
 
-type ChainSpec = GenericChainSpec<Option<Extensions>, ()>;
+type ChainSpec = GenericChainSpec<(), ()>;
 
 //avoid error message escaping
 fn main() {
diff --git a/templates/parachain/node/Cargo.toml b/templates/parachain/node/Cargo.toml
index 86cf0f5826ac..7cf1f1fddc7b 100644
--- a/templates/parachain/node/Cargo.toml
+++ b/templates/parachain/node/Cargo.toml
@@ -73,7 +73,6 @@ cumulus-client-service = { workspace = true, default-features = true }
 cumulus-primitives-core = { workspace = true, default-features = true }
 cumulus-primitives-parachain-inherent = { workspace = true, default-features = true }
 cumulus-relay-chain-interface = { workspace = true, default-features = true }
-cumulus-client-chain-spec-extension = { workspace = true, default-features = true }
 color-print = { workspace = true }
 
 [build-dependencies]
diff --git a/templates/parachain/node/src/chain_spec.rs b/templates/parachain/node/src/chain_spec.rs
index 85389b05cb40..3fa91c026162 100644
--- a/templates/parachain/node/src/chain_spec.rs
+++ b/templates/parachain/node/src/chain_spec.rs
@@ -1,8 +1,9 @@
-use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_primitives_core::ParaId;
 use parachain_template_runtime as runtime;
 use runtime::{AccountId, AuraId, Signature, EXISTENTIAL_DEPOSIT};
+use sc_chain_spec::{ChainSpecExtension, ChainSpecGroup};
 use sc_service::ChainType;
+use serde::{Deserialize, Serialize};
 use sp_core::{sr25519, Pair, Public};
 use sp_runtime::traits::{IdentifyAccount, Verify};
 
@@ -19,6 +20,24 @@ pub fn get_from_seed<TPublic: Public>(seed: &str) -> <TPublic::Pair as Pair>::Pu
 		.public()
 }
 
+/// The extensions for the [`ChainSpec`].
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, ChainSpecGroup, ChainSpecExtension)]
+pub struct Extensions {
+	/// The relay chain of the Parachain.
+	#[serde(alias = "relayChain", alias = "RelayChain")]
+	pub relay_chain: String,
+	/// The id of the Parachain.
+	#[serde(alias = "paraId", alias = "ParaId")]
+	pub para_id: u32,
+}
+
+impl Extensions {
+	/// Try to get the extension from the given `ChainSpec`.
+	pub fn try_get(chain_spec: &dyn sc_service::ChainSpec) -> Option<&Self> {
+		sc_chain_spec::get_extension(chain_spec.extensions())
+	}
+}
+
 type AccountPublic = <Signature as Verify>::Signer;
 
 /// Generate collator keys from seed.
diff --git a/templates/parachain/node/src/cli.rs b/templates/parachain/node/src/cli.rs
index b87e39708ca9..f008e856d99b 100644
--- a/templates/parachain/node/src/cli.rs
+++ b/templates/parachain/node/src/cli.rs
@@ -1,7 +1,5 @@
 use std::path::PathBuf;
 
-use cumulus_client_chain_spec_extension::Extensions;
-
 /// Sub-commands supported by the collator.
 #[allow(clippy::large_enum_variant)]
 #[derive(Debug, clap::Subcommand)]
@@ -101,7 +99,7 @@ impl RelayChainCli {
 		para_config: &sc_service::Configuration,
 		relay_chain_args: impl Iterator<Item = &'a String>,
 	) -> Self {
-		let extension = Extensions::try_get(&*para_config.chain_spec);
+		let extension = crate::chain_spec::Extensions::try_get(&*para_config.chain_spec);
 		let chain_id = extension.map(|e| e.relay_chain.clone());
 		let base_path = para_config.base_path.path().join("polkadot");
 		Self {
diff --git a/templates/parachain/node/src/command.rs b/templates/parachain/node/src/command.rs
index 17014f0e9880..eba7fdcdae71 100644
--- a/templates/parachain/node/src/command.rs
+++ b/templates/parachain/node/src/command.rs
@@ -1,6 +1,5 @@
 use std::net::SocketAddr;
 
-use cumulus_client_chain_spec_extension::Extensions;
 use cumulus_client_service::storage_proof_size::HostFunctions as ReclaimHostFunctions;
 use cumulus_primitives_core::ParaId;
 use frame_benchmarking_cli::{BenchmarkCmd, SUBSTRATE_REFERENCE_HARDWARE};
@@ -227,7 +226,7 @@ pub fn run() -> Result<()> {
 					}))
 					.flatten();
 
-				let para_id = Extensions::try_get(&*config.chain_spec)
+				let para_id = chain_spec::Extensions::try_get(&*config.chain_spec)
 					.map(|e| e.para_id)
 					.ok_or("Could not find parachain ID in chain-spec.")?;
 

From b078a7f2776480fc3cc9d40e981d999e25ac2edc Mon Sep 17 00:00:00 2001
From: Sebastian Kunert <skunert49@gmail.com>
Date: Tue, 25 Jun 2024 14:12:04 +0200
Subject: [PATCH 10/10] Update prdoc

---
 prdoc/pr_4685.prdoc                               | 10 +++++-----
 substrate/bin/utils/chain-spec-builder/src/lib.rs |  7 ++++++-
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/prdoc/pr_4685.prdoc b/prdoc/pr_4685.prdoc
index a9d3bf49a277..e212919ba2e5 100644
--- a/prdoc/pr_4685.prdoc
+++ b/prdoc/pr_4685.prdoc
@@ -1,15 +1,15 @@
 # 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: Chain-spec-builder supports parachain chain-specs and `codeSubstitutes`.
+title: Chain-spec-builder supports `codeSubstitutes`.
 
 doc:
   - audience: Node Operator
     description: |
-      Chain-spec-builder now supports parachain chain-specs. Parachain chain-specs have the `relay_chain` and `para_id` fields.
-      Before this change, the fields would get silently removed when using the chain-spec-builder.
-      In addition, a new subcommand `add-code-substitute` is available. It allows users to provide a runtime that should be used from a given
-      block onwards.
+      A new subcommand `add-code-substitute` is available for the `chain-spec-builder` binary. It allows users to provide a runtime that should be used from a given
+      block onwards. The `codeSubstitutes` field in the chain spec is used to force usage of a given runtime at a given block until the next runtime upgrade. It can be
+      used to progress chains that are stalled due to runtime bugs that prevent block-building. However, parachain usage is only possible in combination with an updated
+      validation function on the relay chain.
 
 crates:
   - name: staging-chain-spec-builder
diff --git a/substrate/bin/utils/chain-spec-builder/src/lib.rs b/substrate/bin/utils/chain-spec-builder/src/lib.rs
index a69ea1c8ff67..6c679f109a00 100644
--- a/substrate/bin/utils/chain-spec-builder/src/lib.rs
+++ b/substrate/bin/utils/chain-spec-builder/src/lib.rs
@@ -226,7 +226,12 @@ pub struct UpdateCodeCmd {
 /// Add a code substitute in the chain spec.
 ///
 /// The `codeSubstitute` object of the chain spec will be updated with the block height as key and
-/// runtime code as value. This operation supports both plain and raw formats.
+/// runtime code as value. This operation supports both plain and raw formats. The `codeSubstitute`
+/// field instructs the node to use the provided runtime code at the given block height. This is
+/// useful when the chain can not progress on its own due to a bug that prevents block-building.
+///
+/// Note: For parachains, the validation function on the relaychain needs to be adjusted too,
+/// otherwise blocks built using the substituted parachain runtime will be rejected.
 #[derive(Parser, Debug, Clone)]
 pub struct AddCodeSubstituteCmd {
 	/// Chain spec to be updated.