Add $isStorageFallback on Codec interface (#5421)

* Add $isStorageFallback on Codec interface

* Rename in CHANGELOG

* Update specs with new naming

* Small formatting adjustments

* Abstract values

* Adjust initialU8a expectation

* Mark old interface as deprecated (& type to never)

* Adjust @deprecated comments

* Add deprecated interfaces to all

packages/api-derive/src/chain/subscribeFinalizedBlocks.ts

@@ -17,7 +17,7 @@ export function subscribeFinalizedBlocks (instanceId: string, api: DeriveApi): (
   return memo(instanceId, (): Observable<SignedBlockExtended> =>
     api.derive.chain.subscribeFinalizedHeads().pipe(
       switchMap((header) =>
-        api.derive.chain.getBlock(header.createdAtHash || header.hash)
+        api.derive.chain.getBlock(header.$createdAtHash || header.hash)
       )
     )
   );

packages/api-derive/src/chain/subscribeFinalizedHeads.ts

@@ -41,7 +41,7 @@ export function subscribeFinalizedHeads (instanceId: string, api: DeriveApi): ()
         const endHash = prevHash;
         const startHash = header.parentHash;
 
-        prevHash = header.createdAtHash = header.hash;
+        prevHash = header.$createdAtHash = header.hash;
 
         return endHash === null || startHash.eq(endHash)
           ? of(header)

packages/api-derive/src/chain/subscribeNewBlocks.ts

@@ -17,7 +17,7 @@ export function subscribeNewBlocks (instanceId: string, api: DeriveApi): () => O
   return memo(instanceId, (): Observable<SignedBlockExtended> =>
     api.derive.chain.subscribeNewHeads().pipe(
       switchMap((header) =>
-        api.derive.chain.getBlock(header.createdAtHash || header.hash)
+        api.derive.chain.getBlock(header.$createdAtHash || header.hash)
       )
     )
   );

packages/api-derive/src/chain/subscribeNewHeads.ts

@@ -37,7 +37,7 @@ export function subscribeNewHeads (instanceId: string, api: DeriveApi): () => Ob
         getAuthorDetails(header, queryAt)
       ),
       map(([header, validators, author]): HeaderExtended => {
-        header.createdAtHash = header.hash;
+        header.$createdAtHash = header.hash;
 
         return createHeaderExtended(header.registry, header, validators, author);
       })

packages/api-derive/src/crowdloan/contributions.ts

@@ -33,7 +33,7 @@ function _getUpdates (api: DeriveApi, paraId: string | number | BN): Observable<
         added = added.concat(...changes.added);
         removed = removed.concat(...changes.removed);
 
-        return of({ added, addedDelta: changes.added, blockHash: events.createdAtHash?.toHex() || '-', removed, removedDelta: changes.removed });
+        return of({ added, addedDelta: changes.added, blockHash: events.$createdAtHash?.toHex() || '-', removed, removedDelta: changes.removed });
       }
 
       return EMPTY;
@@ -52,7 +52,7 @@ function _eventTriggerAll (api: DeriveApi, paraId: string | number | BN): Observ
       );
 
       return items.length
-        ? of(events.createdAtHash?.toHex() || '-')
+        ? of(events.$createdAtHash?.toHex() || '-')
         : EMPTY;
     }),
     startWith('-')

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

@@ -29,5 +29,5 @@ export function extractContributed (paraId: string | number | BN, events: Vec<Fr
       }
 
       return result;
-    }, { added, blockHash: events.createdAtHash?.toHex() || '-', removed });
+    }, { added, blockHash: events.$createdAtHash?.toHex() || '-', removed });
 }

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

@@ -18,7 +18,7 @@ export function createHeaderExtended (registry: Registry, header?: Header, valid
       super(registry, header);
 
       this.#author = author || extractAuthor(this.digest, validators || []);
-      this.createdAtHash = header?.createdAtHash;
+      this.$createdAtHash = header?.$createdAtHash;
     }
 
     /**

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

@@ -46,7 +46,7 @@ export function createSignedBlockExtended (registry: Registry, block?: SignedBlo
       this.#author = author || extractAuthor(this.block.header.digest, validators || []);
       this.#events = events || ([] as EventRecord[]);
       this.#extrinsics = mapExtrinsics(this.block.extrinsics, this.#events);
-      this.createdAtHash = block?.createdAtHash;
+      this.$createdAtHash = block?.$createdAtHash;
     }
 
     /**

packages/rpc-core/src/bundle.ts

@@ -483,7 +483,7 @@ export class RpcCore {
           : meta.modifier.isOptional
             ? registry.createTypeUnsafe(type, [input], { blockHash, isPedantic: true })
             : input
-      ], { blockHash, isOptional: meta.modifier.isOptional, isPedantic: !meta.modifier.isOptional });
+      ], { blockHash, isFallback: isEmpty && !!meta.fallback, isOptional: meta.modifier.isOptional, isPedantic: !meta.modifier.isOptional });
     } catch (error) {
       throw new Error(`Unable to decode storage ${key.section || 'unknown'}.${key.method || 'unknown'}:${entryNum}: ${(error as Error).message}`);
     }

packages/rpc-provider/src/lru.ts

@@ -20,7 +20,8 @@ class LRUNode {
 
 // https://en.wikipedia.org/wiki/Cache_replacement_policies#LRU
 export class LRUCache {
-  readonly capacity: number;
+  public readonly capacity: number;
+
   readonly #data: Map<string, unknown> = new Map();
   readonly #refs: Map<string, LRUNode> = new Map();
 

packages/types-codec/src/abstract/Array.ts

@@ -16,9 +16,16 @@ import { compareArray } from '../utils/compareArray';
  * @noInheritDoc
  */
 export abstract class AbstractArray<T extends Codec> extends Array<T> implements IVec<T> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   /**
    * @description This ensures that operators such as clice, filter, map, etc. return

packages/types-codec/src/abstract/Base.ts

@@ -9,17 +9,22 @@ import type { AnyJson, BareOpts, Codec, Inspect, IU8a, Registry } from '../types
  * @description A type extends the Base class, when it holds a value
  */
 export abstract class AbstractBase<T extends Codec> implements Codec {
-  public createdAtHash?: IU8a;
-
-  public readonly initialU8aLength?: number;
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
 
   public readonly registry: Registry;
 
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
+
   readonly #raw: T;
 
   protected constructor (registry: Registry, value: T, initialU8aLength?: number) {
+    this.$initialU8aLength = initialU8aLength;
     this.#raw = value;
-    this.initialU8aLength = initialU8aLength;
     this.registry = registry;
   }
 

packages/types-codec/src/abstract/Int.ts

@@ -72,14 +72,19 @@ function decodeAbstractInt (value: Exclude<AnyNumber, Uint8Array> | Record<strin
  * @noInheritDoc
  */
 export abstract class AbstractInt extends BN implements INumber {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
-
-  public createdAtHash?: IU8a;
-
   public readonly encodedLength: number;
-
   public readonly isUnsigned: boolean;
 
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
+
   readonly #bitLength: UIntBitLength;
 
   constructor (registry: Registry, value: AnyNumber = 0, bitLength: UIntBitLength = DEFAULT_UINT_BITS, isSigned = false) {
@@ -98,6 +103,7 @@ export abstract class AbstractInt extends BN implements INumber {
     this.registry = registry;
     this.#bitLength = bitLength;
     this.encodedLength = this.#bitLength / 8;
+    this.$initialU8aLength = this.#bitLength / 8;
     this.isUnsigned = !isSigned;
 
     const isNegative = this.isNeg();

packages/types-codec/src/base/Compact.ts

@@ -47,14 +47,18 @@ function decodeCompact<T extends INumber> (registry: Registry, Type: CodecClass<
  * a number and making the compact representation thereof
  */
 export class Compact<T extends INumber> implements ICompact<T> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
-
-  readonly initialU8aLength?: number;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #Type: CodecClass<T>;
-
   readonly #raw: T;
 
   constructor (registry: Registry, Type: CodecClass<T> | string, value: Compact<T> | AnyNumber = 0, { definition, setDefinition = noopSetDefinition }: Options<T> = {}) {
@@ -63,7 +67,7 @@ export class Compact<T extends INumber> implements ICompact<T> {
 
     const [raw, decodedLength] = decodeCompact<T>(registry, this.#Type, value);
 
-    this.initialU8aLength = decodedLength;
+    this.$initialU8aLength = decodedLength;
     this.#raw = raw;
   }
 

packages/types-codec/src/base/DoNotConstruct.ts

@@ -10,9 +10,15 @@ import type { AnyJson, Codec, CodecClass, Inspect, IU8a, Registry } from '../typ
  * An unknown type that fails on construction with the type info
  */
 export class DoNotConstruct implements Codec {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $isStorageFallback?: boolean;
 
   #neverError: Error;
 

packages/types-codec/src/base/Enum.ts

@@ -183,22 +183,22 @@ function decodeEnum (registry: Registry, def: TypesDef, value?: unknown, index?:
  * an extension to enum where the value type is determined by the actual index.
  */
 export class Enum implements IEnum {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #def: TypesDef;
-
   readonly #entryIndex: number;
-
-  readonly initialU8aLength?: number;
-
   readonly #indexes: number[];
-
   readonly #isBasic: boolean;
-
   readonly #isIndexed: boolean;
-
   readonly #raw: Codec;
 
   constructor (registry: Registry, Types: Record<string, string | CodecClass> | Record<string, number> | string[], value?: unknown, index?: number, { definition, setDefinition = noopSetDefinition }: Options = {}) {
@@ -217,8 +217,8 @@ export class Enum implements IEnum {
     this.#entryIndex = this.#indexes.indexOf(decoded.index);
     this.#raw = decoded.value;
 
-    if (this.#raw.initialU8aLength) {
-      this.initialU8aLength = 1 + this.#raw.initialU8aLength;
+    if (this.#raw.$initialU8aLength) {
+      this.$initialU8aLength = 1 + this.#raw.$initialU8aLength;
     }
   }
 

packages/types-codec/src/base/Null.ts

@@ -12,16 +12,18 @@ import { isNull } from '@polkadot/util';
  * Implements a type that does not contain anything (apart from `null`)
  */
 export class Null implements Codec {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly encodedLength = 0;
-
   public readonly isEmpty = true;
-
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
-
-  // Added for compatibility reasons, e.g. see Option
-  public readonly initialU8aLength = 0;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength = 0;
+  public $isStorageFallback?: boolean;
 
   constructor (registry: Registry) {
     this.registry = registry;

packages/types-codec/src/base/Option.ts

@@ -66,14 +66,18 @@ function decodeOption (registry: Registry, Type: CodecClass, value?: unknown): C
  * with a value if/as required/found.
  */
 export class Option<T extends Codec> implements IOption<T> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
-
-  public initialU8aLength?: number;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #Type: CodecClass<T>;
-
   readonly #raw: T;
 
   constructor (registry: Registry, typeName: CodecClass<T> | string, value?: unknown, { definition, setDefinition = noopSetDefinition }: Options<T> = {}) {
@@ -88,8 +92,8 @@ export class Option<T extends Codec> implements IOption<T> {
     this.#Type = Type;
     this.#raw = decoded as T;
 
-    if (decoded && decoded.initialU8aLength) {
-      this.initialU8aLength = 1 + decoded.initialU8aLength;
+    if (decoded?.$initialU8aLength) {
+      this.$initialU8aLength = 1 + decoded.$initialU8aLength;
     }
   }
 

packages/types-codec/src/base/Tuple.ts

@@ -55,8 +55,6 @@ function decodeTuple (registry: Registry, result: Codec[], value: Exclude<AnyTup
  * own type. It extends the base JS `Array` object.
  */
 export class Tuple extends AbstractArray<Codec> implements ITuple<Codec[]> {
-  readonly initialU8aLength?: number;
-
   #Types: Definition;
 
   constructor (registry: Registry, Types: TupleTypes | TupleType, value?: AnyTupleValue, { definition, setDefinition = noopSetDefinition }: Options = {}) {
@@ -70,7 +68,7 @@ export class Tuple extends AbstractArray<Codec> implements ITuple<Codec[]> {
 
     super(registry, Classes[0].length);
 
-    this.initialU8aLength = (
+    this.$initialU8aLength = (
       isU8a(value)
         ? decodeU8a(registry, this, value, Classes)
         : decodeTuple(registry, this, value, Classes)

packages/types-codec/src/base/Vec.ts

@@ -71,8 +71,6 @@ export function decodeVec<T extends Codec> (registry: Registry, result: T[], val
  * specific encoding/decoding on top of the base type.
  */
 export class Vec<T extends Codec> extends AbstractArray<T> {
-  readonly initialU8aLength?: number;
-
   #Type: CodecClass<T>;
 
   constructor (registry: Registry, Type: CodecClass<T> | string, value: Uint8Array | HexString | unknown[] = [], { definition, setDefinition = noopSetDefinition }: Options<T> = {}) {
@@ -82,7 +80,7 @@ export class Vec<T extends Codec> extends AbstractArray<T> {
 
     this.#Type = definition || setDefinition(typeToConstructor<T>(registry, Type));
 
-    this.initialU8aLength = (
+    this.$initialU8aLength = (
       isU8a(decodeFrom)
         ? decodeU8aVec(registry, this, decodeFrom, startAt, this.#Type)
         : decodeVec(registry, this, decodeFrom, startAt, this.#Type)

packages/types-codec/src/base/VecFixed.ts

@@ -25,8 +25,6 @@ function noopSetDefinition <T extends Codec> (d: CodecClass<T>): CodecClass<T> {
  * This manages codec arrays of a fixed length
  */
 export class VecFixed<T extends Codec> extends AbstractArray<T> {
-  readonly initialU8aLength?: number;
-
   #Type: CodecClass<T>;
 
   constructor (registry: Registry, Type: CodecClass<T> | string, length: number, value: Uint8Array | HexString | unknown[] = [] as unknown[], { definition, setDefinition = noopSetDefinition }: Options<T> = {}) {
@@ -34,7 +32,7 @@ export class VecFixed<T extends Codec> extends AbstractArray<T> {
 
     this.#Type = definition || setDefinition(typeToConstructor<T>(registry, Type));
 
-    this.initialU8aLength = (
+    this.$initialU8aLength = (
       isU8a(value)
         ? decodeU8aVec(registry, this, value, 0, this.#Type)
         : decodeVec(registry, this, value, 0, this.#Type)

packages/types-codec/src/extended/BTreeSet.spec.ts

@@ -141,7 +141,7 @@ describe('BTreeSet', (): void => {
       expect(none.toHex()).toEqual('0x00');
       expect(none.encodedLength).toEqual(1);
       expect(
-        (new (BTreeSet.with(U32))(registry, none.toHex())).initialU8aLength
+        (new (BTreeSet.with(U32))(registry, none.toHex())).$initialU8aLength
       ).toEqual(none.encodedLength);
     });
 
@@ -152,7 +152,7 @@ describe('BTreeSet', (): void => {
       expect(some.toHex()).toEqual('0x080100000002000000');
       expect(some.encodedLength).toEqual(1 + (4 * 2));
       expect(
-        (new (BTreeSet.with(U32))(registry, some.toHex())).initialU8aLength
+        (new (BTreeSet.with(U32))(registry, some.toHex())).$initialU8aLength
       ).toEqual(some.encodedLength);
     });
   });

packages/types-codec/src/extended/BTreeSet.ts

@@ -70,11 +70,16 @@ function decodeSet<V extends Codec> (registry: Registry, valType: CodecClass<V>
 }
 
 export class BTreeSet<V extends Codec = Codec> extends Set<V> implements ISet<V> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
-
-  readonly initialU8aLength?: number;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #ValClass: CodecClass<V>;
 
@@ -84,7 +89,7 @@ export class BTreeSet<V extends Codec = Codec> extends Set<V> implements ISet<V>
     super(sortSet(values));
 
     this.registry = registry;
-    this.initialU8aLength = decodedLength;
+    this.$initialU8aLength = decodedLength;
     this.#ValClass = ValClass;
   }
 

packages/types-codec/src/extended/Map.spec.ts

@@ -83,7 +83,7 @@ describe('CodecMap', (): void => {
       expect(none.toHex()).toEqual('0x00');
       expect(none.encodedLength).toEqual(1);
       expect(
-        new CodecMap(registry, Text, Text, none.toHex()).initialU8aLength
+        new CodecMap(registry, Text, Text, none.toHex()).$initialU8aLength
       ).toEqual(none.encodedLength);
     });
 
@@ -97,7 +97,7 @@ describe('CodecMap', (): void => {
       expect(some.toHex()).toEqual('0x0804310c666f6f04320c626172');
       expect(some.encodedLength).toEqual(1 + ((1 + 1) * 2) + ((1 + 3) * 2));
       expect(
-        new CodecMap(registry, Text, Text, some.toHex()).initialU8aLength
+        new CodecMap(registry, Text, Text, some.toHex()).$initialU8aLength
       ).toEqual(some.encodedLength);
     });
   });

packages/types-codec/src/extended/Map.ts

@@ -94,16 +94,19 @@ function decodeMap<K extends Codec, V extends Codec> (registry: Registry, keyTyp
 }
 
 export class CodecMap<K extends Codec = Codec, V extends Codec = Codec> extends Map<K, V> implements IMap<K, V> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #KeyClass: CodecClass<K>;
-
   readonly #ValClass: CodecClass<V>;
-
-  readonly initialU8aLength?: number;
-
   readonly #type: string;
 
   constructor (registry: Registry, keyType: CodecClass<K> | string, valType: CodecClass<V> | string, rawValue: Uint8Array | string | Map<any, any> | undefined, type: 'BTreeMap' | 'HashMap' = 'HashMap') {
@@ -112,7 +115,7 @@ export class CodecMap<K extends Codec = Codec, V extends Codec = Codec> extends
     super(type === 'BTreeMap' ? sortMap(decoded) : decoded);
 
     this.registry = registry;
-    this.initialU8aLength = decodedLength;
+    this.$initialU8aLength = decodedLength;
     this.#KeyClass = KeyClass;
     this.#ValClass = ValClass;
     this.#type = type;

packages/types-codec/src/extended/OptionBool.ts

@@ -33,7 +33,7 @@ export class OptionBool extends Option<Bool> {
         : value
     );
 
-    this.initialU8aLength = 1;
+    this.$initialU8aLength = 1;
   }
 
   /**

packages/types-codec/src/extended/WrapperKeepOpaque.ts

@@ -39,9 +39,7 @@ function decodeRaw<T extends Codec> (registry: Registry, typeName: CodecClass<T>
 
 export class WrapperKeepOpaque<T extends Codec> extends Bytes {
   readonly #Type: CodecClass<T>;
-
   readonly #decoded: T | null;
-
   readonly #opaqueName: OpaqueName;
 
   constructor (registry: Registry, typeName: CodecClass<T> | string, value?: unknown, { opaqueName = 'WrapperKeepOpaque' }: Options = {}) {

packages/types-codec/src/native/Bool.ts

@@ -13,9 +13,16 @@ import { isU8a, u8aToHex } from '@polkadot/util';
  * @noInheritDoc
  */
 export class bool extends Boolean implements Codec {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength = 1;
+  public $isStorageFallback?: boolean;
 
   constructor (registry: Registry, value: bool | AnyBool | Uint8Array | number = false) {
     super(

packages/types-codec/src/native/Date.ts

@@ -34,9 +34,16 @@ function decodeDate (value: CodecDate | Date | AnyNumber): Date {
  * @noInheritDoc
  */
 export class CodecDate extends Date implements INumber {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength = BITLENGTH / 8;
+  public $isStorageFallback?: boolean;
 
   constructor (registry: Registry, value: CodecDate | Date | AnyNumber = 0) {
     super(decodeDate(value));

packages/types-codec/src/native/Float.ts

@@ -19,16 +19,20 @@ interface Options {
  * in some eth_* RPCs
  */
 export class Float extends Number implements IFloat {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
+  public readonly encodedLength: number;
+  public readonly registry: Registry;
+
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
+
   readonly #bitLength: 32 | 64;
 
-  public createdAtHash?: IU8a;
-
-  readonly encodedLength: number;
-
-  readonly initialU8aLength?: number;
-
-  readonly registry: Registry;
-
   constructor (registry: Registry, value?: AnyFloat, { bitLength = 32 }: Options = {}) {
     super(
       isU8a(value) || isHex(value)
@@ -40,7 +44,7 @@ export class Float extends Number implements IFloat {
 
     this.#bitLength = bitLength;
     this.encodedLength = bitLength / 8;
-    this.initialU8aLength = this.encodedLength;
+    this.$initialU8aLength = this.encodedLength;
     this.registry = registry;
   }
 

packages/types-codec/src/native/Json.ts

@@ -22,9 +22,16 @@ function decodeJson (value?: Record<string, unknown> | null): [string, any][] {
  * @noInheritDoc
  */
 export class Json extends Map<string, any> implements Codec {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   constructor (registry: Registry, value?: Record<string, unknown> | null) {
     const decoded = decodeJson(value);

packages/types-codec/src/native/Raw.ts

@@ -16,12 +16,17 @@ import { isAscii, isUndefined, isUtf8, u8aToHex, u8aToString, u8aToU8a } from '@
  * @noInheritDoc
  */
 export class Raw extends Uint8Array implements IU8a {
-  public createdAtHash?: IU8a;
-
-  public readonly initialU8aLength?: number;
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
 
   public readonly registry: Registry;
 
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
+
   /**
    * @description This ensures that operators such as clice, filter, map, etc. return
    * new Array instances (without this we need to apply overrides)
@@ -34,7 +39,7 @@ export class Raw extends Uint8Array implements IU8a {
     super(u8aToU8a(value));
 
     this.registry = registry;
-    this.initialU8aLength = initialU8aLength;
+    this.$initialU8aLength = initialU8aLength;
   }
 
   /**

packages/types-codec/src/native/Set.ts

@@ -92,9 +92,16 @@ function decodeSet (setValues: SetValues, value: string[] | Set<string> | Uint8A
  * a bitwise representation of the values.
  */
 export class CodecSet extends Set<string> implements ISet<string> {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
+
   public readonly registry: Registry;
 
-  public createdAtHash?: IU8a;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
   readonly #allowed: SetValues;
 

packages/types-codec/src/native/Struct.ts

@@ -103,14 +103,18 @@ export class Struct<
   V extends { [K in keyof S]: any } = { [K in keyof S]: any },
   // type names, mapped by key, name of Class in S
   E extends { [K in keyof S]: string } = { [K in keyof S]: string }> extends Map<keyof S, Codec> implements IStruct<keyof S> {
-  public createdAtHash?: IU8a;
-
-  public readonly initialU8aLength?: number;
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
 
   public readonly registry: Registry;
 
-  readonly #jsonMap: Map<keyof S, string>;
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
 
+  readonly #jsonMap: Map<keyof S, string>;
   readonly #Types: Definition;
 
   constructor (registry: Registry, Types: S, value?: V | Map<unknown, unknown> | unknown[] | HexString | null, jsonMap = new Map<string, string>(), { definition, setDefinition = noopSetDefinition }: Options = {}) {
@@ -123,7 +127,7 @@ export class Struct<
 
     super(decoded);
 
-    this.initialU8aLength = decodedLength;
+    this.$initialU8aLength = decodedLength;
     this.registry = registry;
     this.#jsonMap = jsonMap;
     this.#Types = typeMap;

packages/types-codec/src/native/Text.ts

@@ -49,12 +49,17 @@ function decodeText (value?: null | AnyString | AnyU8a | { toString: () => strin
  * @noInheritDoc
  */
 export class Text extends String implements IText {
-  public createdAtHash?: IU8a;
-
-  public readonly initialU8aLength?: number;
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  public initialU8aLength?: never;
 
   public readonly registry: Registry;
 
+  public $createdAtHash?: IU8a;
+  public $initialU8aLength?: number;
+  public $isStorageFallback?: boolean;
+
   #override: string | null = null;
 
   constructor (registry: Registry, value?: null | AnyString | AnyU8a | { toString: () => string }) {
@@ -63,7 +68,7 @@ export class Text extends String implements IText {
     super(str);
 
     this.registry = registry;
-    this.initialU8aLength = decodedLength;
+    this.$initialU8aLength = decodedLength;
   }
 
   /**

packages/types-codec/src/types/codec.ts

@@ -17,11 +17,44 @@ export interface Inspect {
 /**
  * @name Codec
  * @description
- * The base Codec interface. All types implement the interface provided here. Additionally
- * implementors can add their own specific interfaces and helpers with getters and functions.
- * The Codec Base is however required for operating as an encoding/decoding layer
+ * The base Codec interface. All types implement the interface provided here.
+ * Additionally implementors can add their own specific interfaces and helpers
+ * with getters and functions. The Codec Base is however required for operating
+ * as an encoding/decoding layer
  */
 export interface Codec {
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  createdAtHash?: never;
+
+  /** @deprecated This is not populated anymore. Use $initialU8aLength instead. */
+  initialU8aLength?: never;
+
+  /**
+   * @description
+   * The block at which this value was retrieved/created (set to non-empty when
+   * retrieved from storage)
+   */
+  $createdAtHash?: IU8a;
+
+  /**
+   * @description
+   * The length of the initial encoded value (Only available when the value was
+   * constructed from a Uint8Array input)
+   */
+  $initialU8aLength?: number;
+
+  /**
+   * @description
+   * (internal usage) Indicates that the value was created via a fallback. This
+   * is used when with data specified in the metadata when the storage entry is
+   * empty.
+   *
+   * With metadata fallback values (available as defaults on most storage entries)
+   * any empty storage item should erturn the default. (This is the same as the
+   * implementation on the Substrate runtime)
+   */
+  $isStorageFallback?: boolean;
+
   /**
    * @description The length of the value when encoded as a Uint8Array
    */
@@ -32,11 +65,6 @@ export interface Codec {
    */
   readonly hash: IU8a;
 
-  /**
-   * @description The length of the initial encoded value (Only available when constructed from a Uint8Array)
-   */
-  readonly initialU8aLength?: number;
-
   /**
    * @description Checks if the value is an empty value
    */
@@ -47,11 +75,6 @@ export interface Codec {
    */
   readonly registry: Registry;
 
-  /**
-   * @description The block at which this value was retrieved/created (set to non-empty when retrieved from storage)
-   */
-  createdAtHash?: IU8a;
-
   /**
    * @description Compares the value of the input to see if there is a match
    */

packages/types-codec/src/types/registry.ts

@@ -32,6 +32,7 @@ export type RegistryTypes =
 
 export interface CodecCreateOptions {
   blockHash?: Uint8Array | string | null;
+  isFallback?: boolean;
   isOptional?: boolean;
   isPedantic?: boolean;
 }
@@ -51,13 +52,8 @@ export interface Registry {
   readonly chainDecimals: number[];
   readonly chainSS58: number | undefined;
   readonly chainTokens: string[];
-  // readonly knownTypes: RegisteredTypes;
-  // readonly lookup: PortableRegistry;
-  // readonly metadata: MetadataLatest;
-  // readonly unknownTypes: string[];
-  // readonly signedExtensions: string[];
 
-  createdAtHash?: IU8a;
+  $createdAtHash?: IU8a;
 
   findMetaCall (callIndex: Uint8Array): CallFunction;
   findMetaError (errorIndex: Uint8Array | { error: BN, index: BN } | { error: BN | Uint8Array, index: BN }): RegistryError;

packages/types-codec/src/utils/decodeU8a.ts

@@ -41,7 +41,7 @@ export function decodeU8a <T extends Codec = Codec> (registry: Registry, result:
     while (i < count) {
       const value = new Types[i](registry, u8a.subarray(offset));
 
-      offset += value.initialU8aLength || value.encodedLength;
+      offset += value.$initialU8aLength || value.encodedLength;
       result[i] = value;
       i++;
     }
@@ -67,7 +67,7 @@ export function decodeU8aStruct (registry: Registry, result: [string, Codec][],
     while (i < count) {
       const value = new Types[i](registry, u8a.subarray(offset));
 
-      offset += value.initialU8aLength || value.encodedLength;
+      offset += value.$initialU8aLength || value.encodedLength;
       result[i] = [keys[i], value];
       i++;
     }
@@ -93,7 +93,7 @@ export function decodeU8aVec <T extends Codec = Codec> (registry: Registry, resu
     while (i < count) {
       const value = new Type(registry, u8a.subarray(offset));
 
-      offset += value.initialU8aLength || value.encodedLength;
+      offset += value.$initialU8aLength || value.encodedLength;
       result[i] = value;
       i++;
     }

packages/types-create/src/create/type.ts

@@ -44,13 +44,21 @@ function checkPedantic (created: Codec, [value]: unknown[]): void {
 
 // Initializes a type with a value. This also checks for fallbacks and in the cases
 // where isPedantic is specified (storage decoding), also check the format/structure
-function initType<T extends Codec> (registry: Registry, Type: CodecClass, params: unknown[] = [], { blockHash, isOptional, isPedantic }: CreateOptions = {}): T {
-  const created = new (isOptional ? Option.with(Type) : Type)(registry, ...params);
+function initType<T extends Codec> (registry: Registry, Type: CodecClass, params: unknown[] = [], { blockHash, isFallback, isOptional, isPedantic }: CreateOptions = {}): T {
+  const created = new (
+    isOptional
+      ? Option.with(Type)
+      : Type
+  )(registry, ...params);
 
   isPedantic && checkPedantic(created, params);
 
   if (blockHash) {
-    created.createdAtHash = createTypeUnsafe<IU8a>(registry, 'Hash', [blockHash]);
+    created.$createdAtHash = createTypeUnsafe<IU8a>(registry, 'BlockHash', [blockHash]);
+  }
+
+  if (isFallback) {
+    created.$isStorageFallback = true;
   }
 
   return created as T;

packages/types/src/create/registry.ts

@@ -166,43 +166,30 @@ function extractProperties (registry: TypeRegistry, metadata: Metadata): ChainPr
 }
 
 export class TypeRegistry implements Registry {
-  #classes = new Map<string, CodecClass>();
-
-  #definitions = new Map<string, string>();
-
-  #firstCallIndex: Uint8Array | null = null;
-
-  #lookup?: PortableRegistry;
-
-  #metadata?: MetadataLatest;
-
-  #metadataVersion = 0;
-
-  readonly #metadataCalls: Record<string, Record<string, CallFunction>> = {};
-
-  readonly #metadataErrors: Record<string, Record<string, RegistryError>> = {};
-
-  readonly #metadataEvents: Record<string, Record<string, CodecClass<GenericEventData>>> = {};
-
-  readonly #moduleMap: Record<string, string[]> = {};
-
-  #unknownTypes = new Map<string, boolean>();
+  /** @deprecated This is not populated anymore. Use $createdAtHash instead. */
+  public createdAtHash?: never;
 
   #chainProperties?: ChainProperties;
-
+  #classes = new Map<string, CodecClass>();
+  #definitions = new Map<string, string>();
+  #firstCallIndex: Uint8Array | null = null;
   #hasher: (data: Uint8Array) => Uint8Array = blake2AsU8a;
-
-  readonly #knownDefaults: Record<string, CodecClass>;
-
-  readonly #knownDefinitions: Record<string, Definitions>;
-
   #knownTypes: RegisteredTypes = {};
-
+  #lookup?: PortableRegistry;
+  #metadata?: MetadataLatest;
+  #metadataVersion = 0;
   #signedExtensions: string[] = fallbackExtensions;
-
+  #unknownTypes = new Map<string, boolean>();
   #userExtensions?: ExtDef;
 
-  public createdAtHash?: Hash;
+  readonly #knownDefaults: Record<string, CodecClass>;
+  readonly #knownDefinitions: Record<string, Definitions>;
+  readonly #metadataCalls: Record<string, Record<string, CallFunction>> = {};
+  readonly #metadataErrors: Record<string, Record<string, RegistryError>> = {};
+  readonly #metadataEvents: Record<string, Record<string, CodecClass<GenericEventData>>> = {};
+  readonly #moduleMap: Record<string, string[]> = {};
+
+  public $createdAtHash?: Hash;
 
   constructor (createdAtHash?: Hash | Uint8Array | string) {
     this.#knownDefaults = objectSpread({ Json, Metadata, PortableRegistry, Raw }, baseTypes);
@@ -215,7 +202,7 @@ export class TypeRegistry implements Registry {
     }
 
     if (createdAtHash) {
-      this.createdAtHash = this.createType('Hash', createdAtHash);
+      this.$createdAtHash = this.createType('BlockHash', createdAtHash);
     }
   }
 

packages/types/src/extrinsic/ExtrinsicPayload.spec.ts

@@ -23,6 +23,7 @@ describe('ExtrinsicPayload', (): void => {
     const a = new ExtrinsicPayload(registry, TEST, { version: 4 });
     const b = new ExtrinsicPayload(registry, a.toU8a(), { version: 4 });
 
+    expect(a.inspect()).toEqual(b.inspect());
     expect(a.toJSON()).toEqual(b.toJSON());
   });
 
@@ -30,6 +31,7 @@ describe('ExtrinsicPayload', (): void => {
     const a = new ExtrinsicPayload(registry, TEST, { version: 4 });
     const b = new ExtrinsicPayload(registry, a.toHex(), { version: 4 });
 
+    expect(a.inspect()).toEqual(b.inspect());
     expect(a.toJSON()).toEqual(b.toJSON());
   });