Make parser return empty schema when parsing non-spec files

Summary:
Right now, running the codegen parser on regular JavaScript files causes it to throw an error:

https://www.internalfb.com/intern/diffusion/FBS/browsefile/master/xplat/js/react-native-github/packages/react-native-codegen/src/parsers/flow/index.js?commit=1e93f27aac8890f1731650fdcc38b702ae8874e2&lines=59-63%2C106-107

This makes the parser less usable, because you can't simply loop over a list of JavaScript files, and run codegen on them. You need to do some filtering beforehand, or surround each invocation of the parser with a try/catch.

Our codegen schema supports the idea of an empty schema:

```
{
  modules: {}
}
```

To improve the parser's ergonomics, this diff migrates the codegen parser over to returning the empty schema when it cannot detect a Component or NativeModule spec inside a JavaScript file.

Changelog: [Internal]

Reviewed By: JoshuaGross

Differential Revision: D26034052

fbshipit-source-id: c2f15aba9c0e052012396eaed2034537f5918e33

packages/react-native-codegen/src/parsers/flow/index.js

@@ -19,13 +19,17 @@ const {buildComponentSchema} = require('./components');
 const {wrapComponentSchema} = require('./components/schema');
 const {buildModuleSchema} = require('./modules');
 const {wrapModuleSchema} = require('./modules/schema');
-const {createParserErrorCapturer, visit} = require('./utils');
+const {
+  createParserErrorCapturer,
+  visit,
+  isModuleRegistryCall,
+} = require('./utils');
 const invariant = require('invariant');
 
 function getConfigType(
   // TODO(T71778680): Flow-type this node.
   ast: $FlowFixMe,
-): 'module' | 'component' {
+): 'module' | 'component' | 'none' {
   let isComponent = false;
   let isModule = false;
 
@@ -37,6 +41,10 @@ function getConfigType(
       ) {
         isComponent = true;
       }
+
+      if (isModuleRegistryCall(node)) {
+        isModule = true;
+      }
     },
     InterfaceExtends(node) {
       if (node.id.name === 'TurboModule') {
@@ -56,15 +64,19 @@ function getConfigType(
   } else if (isComponent) {
     return 'component';
   } else {
-    throw new Error(
-      'File neither contains a module declaration, nor a component declaration. ' +
-        'For module declarations, please make sure your file has an InterfaceDeclaration extending TurboModule. ' +
-        'For component declarations, please make sure your file has a default export calling the codegenNativeComponent<Props>(...) macro.',
-    );
+    return 'none';
   }
 }
 
 function buildSchema(contents: string, filename: ?string): SchemaType {
+  // Early return for non-Spec JavaScript files
+  if (
+    !contents.includes('codegenNativeComponent') &&
+    !contents.includes('TurboModule')
+  ) {
+    return {modules: {}};
+  }
+
   const ast = flowParser.parse(contents);
   const configType = getConfigType(ast);
 
@@ -103,8 +115,7 @@ function buildSchema(contents: string, filename: ?string): SchemaType {
       return wrapModuleSchema(schema, hasteModuleName);
     }
     default:
-      (configType: empty);
-      throw new Error(`Unsupported config type '${configType}'`);
+      return {modules: {}};
   }
 }
 

packages/react-native-codegen/src/parsers/flow/modules/__tests__/__snapshots__/module-parser-snapshot-test.js.snap

@@ -14,7 +14,7 @@ exports[`RN Codegen Flow Parser Fails with error message NATIVE_MODULES_WITH_UNN
 
 exports[`RN Codegen Flow Parser Fails with error message TWO_NATIVE_EXTENDING_TURBO_MODULE 1`] = `"Module NativeSampleTurboModule: Every NativeModule spec file must declare exactly one NativeModule Flow interface. This file declares 2: 'Spec', and 'Spec2'. Please remove the extraneous Flow interface declarations."`;
 
-exports[`RN Codegen Flow Parser Fails with error message TWO_NATIVE_MODULES_EXPORTED_WITH_DEFAULT 1`] = `"File neither contains a module declaration, nor a component declaration. For module declarations, please make sure your file has an InterfaceDeclaration extending TurboModule. For component declarations, please make sure your file has a default export calling the codegenNativeComponent<Props>(...) macro."`;
+exports[`RN Codegen Flow Parser Fails with error message TWO_NATIVE_MODULES_EXPORTED_WITH_DEFAULT 1`] = `"Module NativeSampleTurboModule: No Flow interfaces extending TurboModule were detected in this NativeModule spec."`;
 
 exports[`RN Codegen Flow Parser can generate fixture ANDROID_ONLY_NATIVE_MODULE 1`] = `
 "{

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

@@ -26,7 +26,12 @@ import type {TypeDeclarationMap} from '../utils.js';
 import type {ParserErrorCapturer} from '../utils';
 import type {NativeModuleTypeAnnotation} from '../../../CodegenSchema.js';
 
-const {resolveTypeAnnotation, getTypes, visit} = require('../utils.js');
+const {
+  resolveTypeAnnotation,
+  getTypes,
+  visit,
+  isModuleRegistryCall,
+} = require('../utils.js');
 const {unwrapNullable, wrapNullable} = require('./utils');
 const {
   IncorrectlyParameterizedFlowGenericParserError,
@@ -528,39 +533,6 @@ function buildPropertySchema(
   };
 }
 
-function isModuleRegistryCall(node) {
-  if (node.type !== 'CallExpression') {
-    return false;
-  }
-
-  const callExpression = node;
-
-  if (callExpression.callee.type !== 'MemberExpression') {
-    return false;
-  }
-
-  const memberExpression = callExpression.callee;
-  if (
-    !(
-      memberExpression.object.type === 'Identifier' &&
-      memberExpression.object.name === 'TurboModuleRegistry'
-    )
-  ) {
-    return false;
-  }
-
-  if (
-    !(
-      memberExpression.property.type === 'Identifier' &&
-      (memberExpression.property.name === 'get' ||
-        memberExpression.property.name === 'getEnforcing')
-    )
-  ) {
-    return false;
-  }
-  return true;
-}
-
 function isModuleInterface(node) {
   return (
     node.type === 'InterfaceDeclaration' &&

packages/react-native-codegen/src/parsers/flow/utils.js

@@ -166,10 +166,45 @@ function visit(
   }
 }
 
+// TODO(T71778680): Flow-type ASTNodes.
+function isModuleRegistryCall(node: $FlowFixMe): boolean {
+  if (node.type !== 'CallExpression') {
+    return false;
+  }
+
+  const callExpression = node;
+
+  if (callExpression.callee.type !== 'MemberExpression') {
+    return false;
+  }
+
+  const memberExpression = callExpression.callee;
+  if (
+    !(
+      memberExpression.object.type === 'Identifier' &&
+      memberExpression.object.name === 'TurboModuleRegistry'
+    )
+  ) {
+    return false;
+  }
+
+  if (
+    !(
+      memberExpression.property.type === 'Identifier' &&
+      (memberExpression.property.name === 'get' ||
+        memberExpression.property.name === 'getEnforcing')
+    )
+  ) {
+    return false;
+  }
+  return true;
+}
+
 module.exports = {
   getValueFromTypes,
   resolveTypeAnnotation,
   createParserErrorCapturer,
   getTypes,
   visit,
+  isModuleRegistryCall,
 };