polkadot-omni-node-lib: emit warnings for aura authority id type assumptions

cumulus/polkadot-omni-node/lib/src/common/runtime.rs

@@ -43,11 +43,28 @@ pub enum AuraConsensusId {
 ///
 /// Most parachains use Sr25519 for Aura consensus, but Asset Hub Polkadot
 /// (formerly Statemint) uses Ed25519.
+///
+/// # Returns
+///
+/// Returns `AuraConsensusId::Ed25519` for chain spec IDs starting with
+/// `asset-hub-polkadot` or `statemint`, and `AuraConsensusId::Sr25519` for all
+/// other chains.
 pub fn aura_id_from_chain_spec_id(id: &str) -> AuraConsensusId {
-	let id = id.replace('_', "-");
-	if id.starts_with("asset-hub-polkadot") || id.starts_with("statemint") {
+	let id_normalized = id.replace('_', "-");
+	if id_normalized.starts_with("asset-hub-polkadot") || id_normalized.starts_with("statemint") {
+		log::warn!(
+			"⚠️  Aura authority id type is assumed to be `ed25519` because the chain spec id \
+			starts with `asset-hub-polkadot` or `statemint`. This is a known special case for \
+			Asset Hub Polkadot (formerly Statemint). If this assumption is wrong for your runtime, \
+			the node may not work correctly."
+		);
 		AuraConsensusId::Ed25519
 	} else {
+		log::warn!(
+			"⚠️  Aura authority id type is assumed to be `sr25519` by default. Runtimes using \
+			`ed25519` for Aura are not yet supported (except for `asset-hub-polkadot` / `statemint`). \
+			If your runtime uses `ed25519` for Aura, it may not work correctly with this node."
+		);
 		AuraConsensusId::Sr25519
 	}
 }
@@ -136,7 +153,7 @@ impl RuntimeResolver for DefaultRuntimeResolver {
 		if !metadata_inspector.pallet_exists(DEFAULT_PARACHAIN_SYSTEM_PALLET_NAME) {
 			log::warn!(
 				r#"⚠️  The parachain system pallet (https://docs.rs/crate/cumulus-pallet-parachain-system/latest) is
-			   missing from the runtime’s metadata. Please check Omni Node docs for runtime conventions:
+			   missing from the runtime's metadata. Please check Omni Node docs for runtime conventions:
 			   https://paritytech.github.io/polkadot-sdk/master/polkadot_sdk_docs/reference_docs/omni_node/index.html#runtime-conventions."#
 			);
 		}

prdoc/pr_11102.prdoc

@@ -0,0 +1,17 @@
+title: 'polkadot-omni-node-lib: emit warnings for aura authority id type assumptions'
+doc:
+- audience: Node Dev
+  description: |-
+    closes https://github.com/paritytech/polkadot-sdk/issues/11026
+
+    This PR adds explicit warnings at node startup to surface these assumptions:
+
+    - When the chain spec id starts with `asset-hub-polkadot` or `statemint`,
+      the node assumes `ed25519` as the Aura authority id type and now emits a
+      warning documenting this specific assumption.
+    - For all other chains, the node assumes `sr25519` by default and now emits
+      a warning noting that `ed25519` runtimes  are not yet
+      supported.
+crates:
+- name: polkadot-omni-node-lib
+  bump: patch