RuntimeGenesiConfig: json macro added

cumulus/parachains/runtimes/assets/asset-hub-rococo/src/genesis_config_presets.rs

@@ -18,6 +18,7 @@
 use crate::*;
 use alloc::{vec, vec::Vec};
 use cumulus_primitives_core::ParaId;
+use frame_support::build_struct_json_patch;
 use hex_literal::hex;
 use parachains_common::{AccountId, AuraId};
 use sp_core::crypto::UncheckedInto;
@@ -33,15 +34,14 @@ fn asset_hub_rococo_genesis(
 	endowment: Balance,
 	id: ParaId,
 ) -> serde_json::Value {
-	let config = RuntimeGenesisConfig {
+	build_struct_json_patch!(RuntimeGenesisConfig {
 		balances: BalancesConfig {
 			balances: endowed_accounts.iter().cloned().map(|k| (k, endowment)).collect(),
 		},
-		parachain_info: ParachainInfoConfig { parachain_id: id, ..Default::default() },
+		parachain_info: ParachainInfoConfig { parachain_id: id },
 		collator_selection: CollatorSelectionConfig {
 			invulnerables: invulnerables.iter().cloned().map(|(acc, _)| acc).collect(),
 			candidacy_bond: ASSET_HUB_ROCOCO_ED * 16,
-			..Default::default()
 		},
 		session: SessionConfig {
 			keys: invulnerables
@@ -54,16 +54,9 @@ fn asset_hub_rococo_genesis(
 					)
 				})
 				.collect(),
-			..Default::default()
 		},
-		polkadot_xcm: PolkadotXcmConfig {
-			safe_xcm_version: Some(SAFE_XCM_VERSION),
-			..Default::default()
-		},
-		..Default::default()
-	};
-
-	serde_json::to_value(config).expect("Could not build genesis config.")
+		polkadot_xcm: PolkadotXcmConfig { safe_xcm_version: Some(SAFE_XCM_VERSION) },
+	})
 }
 
 /// Encapsulates names of predefined presets.

docs/sdk/src/reference_docs/chain_spec_genesis.rs

@@ -100,17 +100,22 @@
 //! others useful for testing.
 //!
 //! Internally, presets can be provided in a number of ways:
-//! - JSON in string form:
-#![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_1)]
-//! - JSON using runtime types to serialize values:
+//! - using [`build_struct_json_patch`] macro (**recommended**):
 #![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_2)]
+//! - JSON using runtime types to serialize values:
 #![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_3)]
+//! - JSON in string form:
+#![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_1)]
+//!
 //! It is worth noting that a preset does not have to be the full `RuntimeGenesisConfig`, in that
 //! sense that it does not have to contain all the keys of the struct. The preset is actually a JSON
 //! patch that will be merged with the default value of `RuntimeGenesisConfig`. This approach should
 //! simplify maintenance of built-in presets. The following example illustrates a runtime genesis
-//! config patch:
+//! config patch with a single key built using [`build_struct_json_patch`] macro:
 #![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_4)]
+//! This results in the following JSON blob:
+#![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/tests/chain_spec_builder_tests.rs", preset_4_json)]
+//!
 //!
 //! ## Note on the importance of testing presets
 //!
@@ -122,15 +127,19 @@
 //!
 //! ## Note on the importance of using the `deny_unknown_fields` attribute
 //!
-//! It is worth noting that it is easy to make a hard-to-spot mistake, as in the following example
-//! ([`FooStruct`] does not contain `fieldC`):
+//! It is worth noting that when manually building preset JSON blobs it is easy to make a
+//! hard-to-spot mistake, as in the following example ([`FooStruct`] does not contain `fieldC`):
 #![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", preset_invalid)]
 //! Even though `preset_invalid` contains a key that does not exist, the deserialization of the JSON
 //! blob does not fail. The misspelling is silently ignored due to the lack of the
 //! [`deny_unknown_fields`] attribute on the [`FooStruct`] struct, which is internally used in
 //! `GenesisConfig`.
 #![doc = docify::embed!("./src/reference_docs/chain_spec_runtime/src/presets.rs", invalid_preset_works)]
 //!
+//! To avoid this problem [`build_struct_json_patch`] macro shall be used whenever possible (it
+//! internally instantiates the struct before serializang it JSON blob, so all unknown fields shall
+//! be caught at compilation time).
+//!
 //! ## Runtime `GenesisConfig` raw format
 //!
 //! A raw format of genesis config contains just the state's keys and values as they are stored in
@@ -179,6 +188,7 @@
 //! [`get_preset`]: frame_support::genesis_builder_helper::get_preset
 //! [`pallet::genesis_build`]: frame_support::pallet_macros::genesis_build
 //! [`pallet::genesis_config`]: frame_support::pallet_macros::genesis_config
+//! [`build_struct_json_patch`]: frame_support::build_struct_json_patch
 //! [`BuildGenesisConfig`]: frame_support::traits::BuildGenesisConfig
 //! [`serde`]: https://serde.rs/field-attrs.html
 //! [`get_storage_for_patch`]: sc_chain_spec::GenesisConfigBuilderRuntimeCaller::get_storage_for_patch

docs/sdk/src/reference_docs/chain_spec_runtime/Cargo.toml

@@ -12,6 +12,7 @@ publish = false
 [dependencies]
 docify = { workspace = true }
 codec = { workspace = true }
+frame-support = { workspace = true }
 scale-info = { workspace = true }
 serde = { workspace = true }
 serde_json = { workspace = true }

docs/sdk/src/reference_docs/chain_spec_runtime/src/pallets.rs

@@ -118,7 +118,7 @@ pub mod pallet_foo {
 		pub some_enum: FooEnum,
 		pub some_struct: FooStruct,
 		#[serde(skip)]
-		_phantom: PhantomData<T>,
+		pub _phantom: PhantomData<T>,
 	}
 
 	#[pallet::genesis_build]

docs/sdk/src/reference_docs/chain_spec_runtime/src/presets.rs

@@ -17,8 +17,12 @@
 
 //! Presets for the chain-spec demo runtime.
 
-use crate::pallets::{FooEnum, SomeFooData1, SomeFooData2};
+use crate::{
+	pallets::{FooEnum, SomeFooData1, SomeFooData2},
+	runtime::{BarConfig, FooConfig, RuntimeGenesisConfig},
+};
 use alloc::vec;
+use frame_support::build_struct_json_patch;
 use serde_json::{json, to_string, Value};
 use sp_application_crypto::Ss58Codec;
 use sp_keyring::AccountKeyring;
@@ -27,7 +31,7 @@ use sp_keyring::AccountKeyring;
 pub const PRESET_1: &str = "preset_1";
 /// A demo preset with real types.
 pub const PRESET_2: &str = "preset_2";
-/// Another demo preset with real types.
+/// Another demo preset with real types and manually created json object.
 pub const PRESET_3: &str = "preset_3";
 /// A single value patch preset.
 pub const PRESET_4: &str = "preset_4";
@@ -58,21 +62,21 @@ fn preset_1() -> Value {
 }
 
 #[docify::export]
-/// Function provides a preset demonstrating how use the actual types to create a preset.
+/// Function provides a preset demonstrating how to create a preset using
+/// [`build_struct_json_patch`] macro.
 fn preset_2() -> Value {
-	json!({
-		"bar": {
-			"initialAccount": AccountKeyring::Ferdie.public().to_ss58check(),
-		},
-		"foo": {
-			"someEnum": FooEnum::Data2(SomeFooData2 { values: vec![12,16] }),
-			"someInteger": 200
+	build_struct_json_patch!(RuntimeGenesisConfig {
+		foo: FooConfig {
+			some_integer: 200,
+			some_enum: FooEnum::Data2(SomeFooData2 { values: vec![0x0c, 0x10] })
 		},
+		bar: BarConfig { initial_account: Some(AccountKeyring::Ferdie.public().into()) },
 	})
 }
 
 #[docify::export]
-/// Function provides a preset demonstrating how use the actual types to create a preset.
+/// Function provides a preset demonstrating how use the actual types to manually create a JSON
+/// representing the preset.
 fn preset_3() -> Value {
 	json!({
 		"bar": {
@@ -92,22 +96,16 @@ fn preset_3() -> Value {
 
 #[docify::export]
 /// Function provides a minimal preset demonstrating how to patch single key in
-/// `RuntimeGenesisConfig`.
-fn preset_4() -> Value {
-	json!({
-		"foo": {
-			"someEnum": {
-				"Data2": {
-					"values": "0x0c0f"
-				}
-			},
-		},
+/// `RuntimeGenesisConfig` using [`build_struct_json_patch`] macro.
+pub fn preset_4() -> Value {
+	build_struct_json_patch!(RuntimeGenesisConfig {
+		foo: FooConfig { some_enum: FooEnum::Data2(SomeFooData2 { values: vec![0x0c, 0x10] }) },
 	})
 }
 
 #[docify::export]
 /// Function provides an invalid preset demonstrating how important is use of
-/// [`deny_unknown_fields`] in data structures used in `GenesisConfig`.
+/// `deny_unknown_fields` in data structures used in `GenesisConfig`.
 fn preset_invalid() -> Value {
 	json!({
 		"foo": {

docs/sdk/src/reference_docs/chain_spec_runtime/tests/chain_spec_builder_tests.rs

@@ -58,7 +58,7 @@ fn get_preset() {
 
 	let output: serde_json::Value = serde_json::from_slice(&output.stdout).unwrap();
 
-	//note: copy of chain_spec_guide_runtime::preset_1
+	//note: copy of chain_spec_guide_runtime::preset_2
 	let expected_output = json!({
 		"bar": {
 			"initialAccount": "5CiPPseXPECbkjWCa6MnjNokrgYjMqmKndv2rSnekmSK2DjL",
@@ -186,3 +186,20 @@ fn generate_para_chain_spec() {
 	});
 	assert_eq!(output, expected_output, "Output did not match expected");
 }
+
+#[test]
+#[docify::export]
+fn preset_4_json() {
+	assert_eq!(
+		chain_spec_guide_runtime::presets::preset_4(),
+		json!({
+			"foo": {
+				"someEnum": {
+					"Data2": {
+						"values": "0x0c10"
+					}
+				},
+			},
+		})
+	);
+}

polkadot/runtime/westend/src/genesis_config_presets.rs

@@ -23,6 +23,7 @@ use crate::{
 #[cfg(not(feature = "std"))]
 use alloc::format;
 use alloc::{vec, vec::Vec};
+use frame_support::build_struct_json_patch;
 use pallet_staking::{Forcing, StakerStatus};
 use polkadot_primitives::{AccountId, AssignmentId, SchedulerParams, ValidatorId};
 use sp_authority_discovery::AuthorityId as AuthorityDiscoveryId;
@@ -170,7 +171,7 @@ fn westend_testnet_genesis(
 	const ENDOWMENT: u128 = 1_000_000 * WND;
 	const STASH: u128 = 100 * WND;
 
-	let config = RuntimeGenesisConfig {
+	build_struct_json_patch!(RuntimeGenesisConfig {
 		balances: BalancesConfig {
 			balances: endowed_accounts.iter().map(|k| (k.clone(), ENDOWMENT)).collect::<Vec<_>>(),
 		},
@@ -192,7 +193,6 @@ fn westend_testnet_genesis(
 					)
 				})
 				.collect::<Vec<_>>(),
-			..Default::default()
 		},
 		staking: StakingConfig {
 			minimum_validator_count: 1,
@@ -204,19 +204,12 @@ fn westend_testnet_genesis(
 			invulnerables: initial_authorities.iter().map(|x| x.0.clone()).collect::<Vec<_>>(),
 			force_era: Forcing::NotForcing,
 			slash_reward_fraction: Perbill::from_percent(10),
-			..Default::default()
 		},
-		babe: BabeConfig { epoch_config: BABE_GENESIS_EPOCH_CONFIG, ..Default::default() },
+		babe: BabeConfig { epoch_config: BABE_GENESIS_EPOCH_CONFIG },
 		sudo: SudoConfig { key: Some(root_key) },
 		configuration: ConfigurationConfig { config: default_parachains_host_configuration() },
-		registrar: RegistrarConfig {
-			next_free_para_id: polkadot_primitives::LOWEST_PUBLIC_ID,
-			..Default::default()
-		},
-		..Default::default()
-	};
-
-	serde_json::to_value(config).expect("Could not build genesis config.")
+		registrar: RegistrarConfig { next_free_para_id: polkadot_primitives::LOWEST_PUBLIC_ID },
+	})
 }
 
 // staging_testnet

prdoc/pr_5813.prdoc

@@ -0,0 +1,18 @@
+title: "build_struct_json_patch macro added"
+
+doc:
+  - audience: Runtime Dev
+    description: |
+      This PR adds a macro that allows to construct a RuntimeGenesisConfig preset 
+      containing only provided fields, while performing the validation of the
+      entire struct.
+
+      Related issue: https://github.com/paritytech/polkadot-sdk/issues/5700
+
+crates:
+  - name: frame-support
+    bump: minor
+  - name: asset-hub-rococo-runtime
+    bump: patch
+  - name: westend-runtime
+    bump: patch

substrate/frame/support/Cargo.toml

@@ -71,6 +71,7 @@ pretty_assertions = { workspace = true }
 sp-timestamp = { workspace = true }
 frame-system = { workspace = true, default-features = true }
 sp-crypto-hashing = { workspace = true, default-features = true }
+Inflector = { workspace = true }
 
 [features]
 default = ["std"]