Cater for Abi type offsets in 1+ (#3514)

* Cater for Abi type offsets in 1+

* Update packages/api-contract/src/MetaRegistry.ts

packages/api-contract/src/Abi.ts

@@ -45,13 +45,13 @@ export class Abi {
     assert(isObject(json) && !Array.isArray(json) && json.metadataVersion && isObject(json.spec) && !Array.isArray(json.spec) && Array.isArray(json.spec.constructors) && Array.isArray(json.spec.messages), 'Invalid JSON ABI structure supplied, expected a recent metadata version');
 
     this.json = json;
-    this.registry = new MetaRegistry(chainProperties);
+    this.registry = new MetaRegistry(json.metadataVersion as string, chainProperties);
     this.project = this.registry.createType('ContractProject', json);
 
     this.registry.setMetaTypes(this.project.types);
 
     this.project.types.forEach((_, index) =>
-      this.registry.getMetaTypeDef({ type: this.registry.createType('SiLookupTypeId', index + 1) })
+      this.registry.getMetaTypeDef({ type: this.registry.createType('SiLookupTypeId', index + this.registry.typeOffset) })
     );
     this.constructors = this.project.spec.constructors.map((spec: ContractConstructorSpec, index) =>
       this.#createMessage(spec, index, {

packages/api-contract/src/MetaRegistry.ts

@@ -14,8 +14,8 @@ interface PartialTypeSpec {
 }
 
 // convert the offset into project-specific, index-1
-export function getRegistryOffset (id: SiLookupTypeId): number {
-  return id.toNumber() - 1;
+export function getRegistryOffset (id: SiLookupTypeId, typeOffset: number): number {
+  return id.toNumber() - typeOffset;
 }
 
 const PRIMITIVE_ALIAS: Record<string, keyof InterfaceTypes> = {
@@ -28,11 +28,18 @@ const PRIMITIVE_ALWAYS = ['AccountId', 'AccountIndex', 'Address', 'Balance'];
 export class MetaRegistry extends TypeRegistry {
   public readonly metaTypeDefs: TypeDef[] = [];
 
+  public readonly typeOffset;
+
   #siTypes: SiType[] = [];
 
-  constructor (chainProperties?: ChainProperties) {
+  constructor (metadataVersion: string, chainProperties?: ChainProperties) {
     super();
 
+    const [major] = metadataVersion.split('.');
+
+    // type indexes are 1-based pre-1.0 and 0-based post-1.0
+    this.typeOffset = major === '0' ? 1 : 0;
+
     if (chainProperties) {
       this.setChainProperties(chainProperties);
     }
@@ -43,7 +50,7 @@ export class MetaRegistry extends TypeRegistry {
   }
 
   public getMetaTypeDef (typeSpec: PartialTypeSpec): TypeDef {
-    const offset = getRegistryOffset(typeSpec.type);
+    const offset = getRegistryOffset(typeSpec.type, this.typeOffset);
     let typeDef = this.metaTypeDefs[offset];
 
     if (!typeDef) {
@@ -78,7 +85,7 @@ export class MetaRegistry extends TypeRegistry {
   }
 
   #getMetaType = (id: SiLookupTypeId): SiType => {
-    const type = this.#siTypes[getRegistryOffset(id)];
+    const type = this.#siTypes[getRegistryOffset(id, this.typeOffset)];
 
     assert(!isUndefined(type), () => `getMetaType:: Unable to find ${id.toNumber()} in type values`);