Codegen: List type aliases in modules schema

Summary:
The current parser behavior flattens out any object type aliases into ObjectTypeAnnotations. Generators can treat these as regular objects and generate the applicable native code. This, however, can lead to repetition whenever an object type alias is re-used in the same native module.

I propose we treat these as a special case, using a TypeAliasTypeAnnotation to denote them as type aliases. Generators can look up the actual signature for a given object alias by referring to the "aliases" array that is provided in the schema.

**Proposed schema change:**

Adds an "aliases" key to each module in the schema:

```
export type NativeModuleShape = $ReadOnly<{|
  properties: $ReadOnlyArray<NativeModuleMethodTypeShape>,
  aliases: $ReadOnlyArray<{|
    name: string,
    typeAnnotation:
      | $ReadOnly<{|
          type: 'ObjectTypeAnnotation',
          properties: $ReadOnlyArray<ObjectParamTypeAnnotation>,
        |}>
      | $ReadOnly<TypeAliasTypeAnnotation>,
  |}>,
|}>;
```

Example:
```
{
  modules: {
    SampleTurboModule: {
      nativeModules: {
        SampleTurboModule: {
          aliases: [],
          properties: [],
        },
      },
    },
  },
}
```

Method parameters will now support the new 'TypeAliasTypeAnnotation' wherever a param might have used a 'ObjectTypeAnnotation':

```
export type TypeAliasTypeAnnotation = $ReadOnly<{|
  type: 'TypeAliasTypeAnnotation',
  name: string,
|}>;
```

Changelog: [Internal]

Reviewed By: RSNara

Differential Revision: D22200700

fbshipit-source-id: 15684620783c752f2fb482ba4b88d1fd1cc07540

Author: hramos

packages/react-native-codegen/src/CodegenSchema.js

@@ -55,6 +55,11 @@ export type StringTypeAnnotation = $ReadOnly<{|
   type: 'StringTypeAnnotation',
 |}>;
 
+export type TypeAliasTypeAnnotation = $ReadOnly<{|
+  type: 'TypeAliasTypeAnnotation',
+  name: string,
+|}>;
+
 export type EventObjectPropertyType =
   | $ReadOnly<{|
       type: 'BooleanTypeAnnotation',
@@ -223,19 +228,25 @@ export type FunctionTypeAnnotationParamTypeAnnotation =
     |}>
   | $ReadOnly<{|
       type: 'ArrayTypeAnnotation',
-      elementType: ?FunctionTypeAnnotationParamTypeAnnotation,
+      elementType:
+        | ?FunctionTypeAnnotationParamTypeAnnotation
+        | ?TypeAliasTypeAnnotation,
     |}>
   | $ReadOnly<{|
       type: 'ObjectTypeAnnotation',
       properties: ?$ReadOnlyArray<ObjectParamTypeAnnotation>,
     |}>;
 
-export type FunctionTypeAnnotationReturnArrayElementType = FunctionTypeAnnotationParamTypeAnnotation;
+export type FunctionTypeAnnotationReturnArrayElementType =
+  | FunctionTypeAnnotationParamTypeAnnotation
+  | TypeAliasTypeAnnotation;
 
 export type ObjectParamTypeAnnotation = $ReadOnly<{|
   optional: boolean,
   name: string,
-  typeAnnotation?: FunctionTypeAnnotationParamTypeAnnotation, // TODO (T67898313): Workaround for NativeLinking's use of union type, typeAnnotations should not be optional
+  typeAnnotation?:
+    | FunctionTypeAnnotationParamTypeAnnotation
+    | TypeAliasTypeAnnotation, // TODO (T67898313): Workaround for NativeLinking's use of union type, typeAnnotations should not be optional
 |}>;
 
 export type FunctionTypeAnnotationReturn =
@@ -265,7 +276,9 @@ export type FunctionTypeAnnotationReturn =
 export type FunctionTypeAnnotationParam = $ReadOnly<{|
   nullable: boolean,
   name: string,
-  typeAnnotation: FunctionTypeAnnotationParamTypeAnnotation,
+  typeAnnotation:
+    | FunctionTypeAnnotationParamTypeAnnotation
+    | TypeAliasTypeAnnotation,
 |}>;
 
 export type FunctionTypeAnnotation = $ReadOnly<{|
@@ -280,7 +293,13 @@ export type NativeModuleMethodTypeShape = $ReadOnly<{|
   typeAnnotation: FunctionTypeAnnotation,
 |}>;
 
+export type ObjectTypeAliasTypeShape = $ReadOnly<{|
+  type: 'ObjectTypeAnnotation',
+  properties: $ReadOnlyArray<ObjectParamTypeAnnotation>,
+|}>;
+
 export type NativeModuleShape = $ReadOnly<{|
+  aliases: $ReadOnly<{[aliasName: string]: ObjectTypeAliasTypeShape, ...}>,
   properties: $ReadOnlyArray<NativeModuleMethodTypeShape>,
 |}>;
 

packages/react-native-codegen/src/generators/modules/GenerateModuleCpp.js

@@ -75,7 +75,7 @@ function traverseArg(arg, index): string {
         default:
           (typeAnnotation.name: empty);
           throw new Error(
-            `Unknown prop type for "${arg.name}, found: ${typeAnnotation.name}"`,
+            `Unknown prop type for "${arg.name}", found: "${typeAnnotation.name}"`,
           );
       }
     case 'StringTypeAnnotation':
@@ -91,6 +91,7 @@ function traverseArg(arg, index): string {
     case 'FunctionTypeAnnotation':
       return `std::move(${wrap('.getObject(rt).getFunction(rt)')})`;
     case 'GenericObjectTypeAnnotation':
+    case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'ObjectTypeAnnotation':
       return wrap('.getObject(rt)');
     case 'AnyTypeAnnotation':
@@ -99,7 +100,7 @@ function traverseArg(arg, index): string {
       // TODO (T65847278): Figure out why this does not work.
       // (typeAnnotation.type: empty);
       throw new Error(
-        `Unknown prop type for "${arg.name}, found: ${typeAnnotation.type}"`,
+        `Unknown prop type for "${arg.name}", found: "${typeAnnotation.type}"`,
       );
   }
 }

packages/react-native-codegen/src/generators/modules/GenerateModuleH.js

@@ -74,6 +74,7 @@ function translatePrimitiveJSTypeToCpp(
       return 'int';
     case 'BooleanTypeAnnotation':
       return 'bool';
+    // case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'GenericObjectTypeAnnotation':
     case 'ObjectTypeAnnotation':
       return 'jsi::Object';

packages/react-native-codegen/src/generators/modules/GenerateModuleHObjCpp.js

@@ -124,6 +124,7 @@ function translatePrimitiveJSTypeToObjCType(
       return nullable ? 'NSNumber *' : 'double';
     case 'BooleanTypeAnnotation':
       return nullable ? 'NSNumber * _Nullable' : 'BOOL';
+    case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'GenericObjectTypeAnnotation':
       return wrapIntoNullableIfNeeded('NSDictionary *');
     case 'ArrayTypeAnnotation':

packages/react-native-codegen/src/generators/modules/ObjCppUtils/GenerateStructs.js

@@ -92,6 +92,7 @@ function getElementTypeForArray(
       return 'double';
     case 'ObjectTypeAnnotation':
       return getNamespacedStructName(name, property) + 'Element';
+    case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'GenericObjectTypeAnnotation':
       // TODO(T67565166): Generic objects are not type safe and should be disallowed in the schema. This case should throw an error once it is disallowed in schema.
       console.error(
@@ -228,6 +229,7 @@ function getInlineMethodImplementation(
         return `RCTBridgingToBool(${element})`;
       case 'ObjectTypeAnnotation':
         return `${getNamespacedStructName(name, property)}Element(${element})`;
+      case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
       case 'GenericObjectTypeAnnotation':
         return element;
       case 'AnyObjectTypeAnnotation':

packages/react-native-codegen/src/generators/modules/ObjCppUtils/GenerateStructsForConstants.js

@@ -96,6 +96,7 @@ function getBuilderInputFieldDeclaration(
           property.name,
         )}::Builder`,
       );
+    case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'GenericObjectTypeAnnotation':
     case 'AnyTypeAnnotation':
       if (property.optional) {
@@ -185,6 +186,7 @@ function getObjectProperty(property: ObjectParamTypeAnnotation): string {
     case 'BooleanTypeAnnotation':
       return boolGetter(property.name, property.optional);
     case 'StringTypeAnnotation':
+    case 'TypeAliasTypeAnnotation': // TODO: Handle aliases
     case 'GenericObjectTypeAnnotation':
     case 'AnyTypeAnnotation':
       return safeGetter(property.name, property.optional);

packages/react-native-codegen/src/generators/modules/__test_fixtures__/fixtures.js

@@ -17,6 +17,7 @@ const EMPTY_NATIVE_MODULES: SchemaType = {
     SampleTurboModule: {
       nativeModules: {
         SampleTurboModule: {
+          aliases: {},
           properties: [],
         },
       },
@@ -29,6 +30,7 @@ const SIMPLE_NATIVE_MODULES: SchemaType = {
     SampleTurboModule: {
       nativeModules: {
         SampleTurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'getConstants',
@@ -291,6 +293,7 @@ const TWO_MODULES_SAME_FILE: SchemaType = {
     NativeSampleTurboModule: {
       nativeModules: {
         SampleTurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'voidFunc',
@@ -307,6 +310,7 @@ const TWO_MODULES_SAME_FILE: SchemaType = {
           ],
         },
         Sample2TurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'voidFunc',
@@ -332,6 +336,7 @@ const TWO_MODULES_DIFFERENT_FILES: SchemaType = {
     NativeSampleTurboModule: {
       nativeModules: {
         SampleTurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'voidFunc',
@@ -352,6 +357,7 @@ const TWO_MODULES_DIFFERENT_FILES: SchemaType = {
     NativeSampleTurboModule2: {
       nativeModules: {
         Sample2TurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'getConstants',
@@ -390,6 +396,7 @@ const COMPLEX_OBJECTS: SchemaType = {
     NativeSampleTurboModule: {
       nativeModules: {
         SampleTurboModule: {
+          aliases: {},
           properties: [
             {
               name: 'difficult',

packages/react-native-codegen/src/parsers/flow/modules/__test_fixtures__/fixtures.js

@@ -154,12 +154,54 @@ type Num2 = Num;
 export type Void = void;
 export type A = number;
 export type B = number;
+export type ObjectAlias = {|
+  x: number,
+  y: number,
+  label: string,
+  truthy: boolean,
+|}
 
 export interface Spec extends TurboModule {
   // Exported methods.
   +getNumber: Num2;
   +getVoid: () => Void;
   +getArray: (a: Array<A>) => {| a: B |};
+  +getStringFromAlias: (a: ObjectAlias) => string;
+}
+
+export default TurboModuleRegistry.getEnforcing<Spec>('SampleTurboModule');
+
+`;
+
+const NATIVE_MODULE_WITH_NESTED_ALIASES = `
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+'use strict';
+
+import type {TurboModule} from '../RCTExport';
+import * as TurboModuleRegistry from '../TurboModuleRegistry';
+
+type Bar = {|
+  z: number
+|};
+
+type Foo = {|
+  bar1: Bar,
+  bar2: Bar,
+|};
+
+export interface Spec extends TurboModule {
+  // Exported methods.
+  foo1: (x: Foo) => void;
+  foo2: (x: Foo) => void;
 }
 
 export default TurboModuleRegistry.getEnforcing<Spec>('SampleTurboModule');
@@ -459,6 +501,7 @@ module.exports = {
   NATIVE_MODULE_WITH_ARRAY_WITH_UNION_AND_TOUPLE,
   NATIVE_MODULE_WITH_FLOAT_AND_INT32,
   NATIVE_MODULE_WITH_ALIASES,
+  NATIVE_MODULE_WITH_NESTED_ALIASES,
   NATIVE_MODULE_WITH_PROMISE,
   NATIVE_MODULE_WITH_COMPLEX_OBJECTS,
   NATIVE_MODULE_WITH_COMPLEX_OBJECTS_WITH_NULLABLE_KEY,