Support LegacyAminoPubKey in decodePubkey

packages/proto-signing/src/pubkey.ts

@@ -3,6 +3,7 @@ import {
   encodeSecp256k1Pubkey,
   isMultisigThresholdPubkey,
   isSecp256k1Pubkey,
+  MultisigThresholdPubkey,
   Pubkey,
   SinglePubkey,
 } from "@cosmjs/amino";
@@ -36,16 +37,37 @@ export function encodePubkey(pubkey: Pubkey): Any {
   }
 }
 
-export function decodePubkey(pubkey?: Any | null): SinglePubkey | null {
+function decodeSinglePubkey(pubkey: Any): SinglePubkey {
-  if (!pubkey || !pubkey.value) {
-    return null;
-  }
-
   switch (pubkey.typeUrl) {
     case "/cosmos.crypto.secp256k1.PubKey": {
       const { key } = PubKey.decode(pubkey.value);
       return encodeSecp256k1Pubkey(key);
     }
+    default:
+      throw new Error(`Pubkey type_url ${pubkey.typeUrl} not recognized as single public key type`);
+  }
+}
+
+export function decodePubkey(pubkey?: Any | null): Pubkey | null {
+  if (!pubkey || !pubkey.value) {
+    return null;
+  }
+
+  switch (pubkey.typeUrl) {
+    case "/cosmos.crypto.secp256k1.PubKey": {
+      return decodeSinglePubkey(pubkey);
+    }
+    case "/cosmos.crypto.multisig.LegacyAminoPubKey": {
+      const { threshold, publicKeys } = LegacyAminoPubKey.decode(pubkey.value);
+      const out: MultisigThresholdPubkey = {
+        type: "tendermint/PubKeyMultisigThreshold",
+        value: {
+          threshold: threshold.toString(),
+          pubkeys: publicKeys.map(decodeSinglePubkey),
+        },
+      };
+      return out;
+    }
     default:
       throw new Error(`Pubkey type_url ${pubkey.typeUrl} not recognized`);
   }