Fix author extraction (both POW & BABE) (#3299)

* Fix author extaction for Babeb session-end

* Fix extraction from Seal

packages/api-derive/src/type/util.ts

@@ -5,20 +5,43 @@ import type { AccountId, Digest } from '@polkadot/types/interfaces';
 
 export function extractAuthor (digest: Digest, sessionValidators: AccountId[] = []): AccountId | undefined {
   const [citem] = digest.logs.filter(({ type }) => type === 'Consensus');
+  const [pitem] = digest.logs.filter(({ type }) => type === 'PreRuntime');
+  const [sitem] = digest.logs.filter(({ type }) => type === 'Seal');
 
-  if (citem) {
-    const [engine, data] = citem.asConsensus;
+  let accountId: AccountId | undefined;
 
-    return engine.extractAuthor(data, sessionValidators);
-  } else {
-    const [pitem] = digest.logs.filter(({ type }) => type === 'PreRuntime');
-
-    if (pitem) {
+  // This is critical to be first for BABE (before Consensus)
+  // If not first, we end up dropping the author at session-end
+  if (pitem) {
+    try {
       const [engine, data] = pitem.asPreRuntime;
 
-      return engine.extractAuthor(data, sessionValidators);
+      accountId = engine.extractAuthor(data, sessionValidators);
+    } catch {
+      // ignore
     }
   }
 
-  return undefined;
+  if (!accountId && citem) {
+    try {
+      const [engine, data] = citem.asConsensus;
+
+      accountId = engine.extractAuthor(data, sessionValidators);
+    } catch {
+      // ignore
+    }
+  }
+
+  // SEAL, still used in e.g. Kulupu for pow
+  if (!accountId && sitem) {
+    try {
+      const [engine, data] = sitem.asSeal;
+
+      accountId = engine.extractAuthor(data, sessionValidators);
+    } catch {
+      // ignore
+    }
+  }
+
+  return accountId;
 }