Handle double-encoded Bytes in fallback/constants (#2113)

* Handle double-encoded Bytes in fallback/constants

* Fix import, bypass for tests

packages/metadata/src/Decorated/consts/fromMetadata/fromMetadata.spec.ts

@@ -2,25 +2,34 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import { Constants } from '../../types';
+
 import { Metadata, TypeRegistry } from '@polkadot/types';
 
 import rpcMetadata from '../../../Metadata/static';
+import rpcMetadataV10 from '../../../Metadata/v10/static';
 import fromMetadata from '../fromMetadata';
 
-// Use the pre-generated metadata
-const registry = new TypeRegistry();
-const metadata = new Metadata(registry, rpcMetadata);
-const consts = fromMetadata(registry, metadata);
+function init (meta: string): [Constants, TypeRegistry] {
+  const registry = new TypeRegistry();
+  const metadata = new Metadata(registry, meta);
+
+  return [fromMetadata(registry, metadata), registry];
+}
 
 describe('fromMetadata', (): void => {
   it('should return constants with the correct type and value', (): void => {
+    const [consts, registry] = init(rpcMetadata);
+
     expect(consts.democracy.cooloffPeriod).toBeInstanceOf(registry.createClass('BlockNumber'));
     // 3 second blocks, 28 days
     expect(consts.democracy.cooloffPeriod.toNumber()).toEqual(28 * 24 * 60 * (60 / 3));
   });
 
   // removed from session
-  it.skip('correctly handles bytes', (): void => {
+  it('correctly handles bytes', (): void => {
+    const [consts] = init(rpcMetadataV10);
+
     // 0x34 removes as the length prefix removed
     expect(consts.session.dedupKeyPrefix.toHex()).toEqual('0x3a73657373696f6e3a6b657973');
   });

packages/metadata/src/Decorated/consts/fromMetadata/index.ts

@@ -6,12 +6,10 @@ import { Registry } from '@polkadot/types/types';
 import { Constants, ConstantCodec, ModuleConstants } from '../../types';
 
 import { createTypeUnsafe } from '@polkadot/types/create';
-import { stringCamelCase } from '@polkadot/util';
+import { hexToU8a, stringCamelCase } from '@polkadot/util';
 
 import Metadata from '../../../Metadata';
 
-const AS_STRIPPED = ['Bytes'];
-
 /** @internal */
 export default function fromMetadata (registry: Registry, metadata: Metadata): Constants {
   return metadata.asLatest.modules.reduce((result: Constants, moduleMetadata): Constants => {
@@ -23,19 +21,10 @@ export default function fromMetadata (registry: Registry, metadata: Metadata): C
 
     // For access, we change the index names, i.e. Democracy.EnactmentPeriod -> democracy.enactmentPeriod
     result[stringCamelCase(name.toString())] = moduleMetadata.constants.reduce((newModule: ModuleConstants, meta): ModuleConstants => {
-      // in the case of Bytes, the data has a length prefix encoded when received,
-      // leading to double-encoding unless removed
+      // convert to the natural type as received
       const type = meta.type.toString();
-      const codec: ConstantCodec = createTypeUnsafe(registry, type, [
-        AS_STRIPPED.includes(type)
-          ? meta.value.toU8a(true)
-          : meta.value
-      ]);
+      const codec: ConstantCodec = createTypeUnsafe(registry, type, [hexToU8a(meta.value.toHex())]);
 
-      // This is not a perfect idea, however as it stands with number-only constants on the metadata
-      // does not have any effect. However, this could become problematic in cases where items are
-      // exposed that contain their own metadata. As of now, the compatibility with current, e.g.
-      // storage is the driving factor, one consistent way of handling interfaces
       codec.meta = meta;
       newModule[stringCamelCase(meta.name.toString())] = codec;
 

packages/rpc-core/src/index.ts

@@ -12,7 +12,7 @@ import { combineLatest, from, Observable, Observer, of, throwError } from 'rxjs'
 import { catchError, map, publishReplay, refCount, switchMap } from 'rxjs/operators';
 import jsonrpc from '@polkadot/types/interfaces/jsonrpc';
 import { Option, StorageKey, Vec, createClass, createTypeUnsafe } from '@polkadot/types';
-import { assert, isFunction, isNull, isNumber, isUndefined, logger, u8aToU8a } from '@polkadot/util';
+import { assert, hexToU8a, isFunction, isNull, isNumber, isUndefined, logger, u8aToU8a } from '@polkadot/util';
 
 import { drr } from './rxjs';
 
@@ -370,7 +370,13 @@ export default class Rpc implements RpcInterface {
       );
     }
 
-    return createTypeUnsafe(this.registry, type, [isEmpty ? meta.fallback : input], true);
+    return createTypeUnsafe(this.registry, type, [
+      isEmpty
+        ? meta.fallback
+          ? hexToU8a(meta.fallback.toHex())
+          : undefined
+        : input
+    ], true);
   }
 
   private formatStorageSet (keys: Vec<StorageKey>, changes: [string, string | null][]): Codec[] {
@@ -428,6 +434,12 @@ export default class Rpc implements RpcInterface {
       );
     }
 
-    return createTypeUnsafe(this.registry, type, [isEmpty ? meta.fallback : input], true);
+    return createTypeUnsafe(this.registry, type, [
+      isEmpty
+        ? meta.fallback
+          ? hexToU8a(meta.fallback.toHex())
+          : undefined
+        : input
+    ], true);
   }
 }