Move check for graphql string in source files to language plugin (#2811)

Summary:
This moves the check for the string `graphql` in source files to the JS language plugin, away from `RelaySourceModuleParser`. This has two reasons:

1. Language plugins might not require/use the string 'graphql'. I have that case when emitting ReasonML types - Writing GraphQL there looks like `[%relay.mutation ...]` and `[%relay.query ...]`, so `graphql` is not naturally inside any of the source files I want the compiler to pick up.
2. The requirement was quite "hidden" and it took me a few hours to understand why my files weren't picked up even though they seemed to satisfy all requirements of the compiler + configuration. So, also reducing confusion.

If this lands I'll PR the TypeScript language plugin to add the same type of check into that as well.
Pull Request resolved: #2811

Reviewed By: jstejada

Differential Revision: D19856119

Pulled By: alunyov

fbshipit-source-id: 864c75020db6993b0a3702c38a8ab22b7933073a

packages/relay-compiler/bin/RelayCompilerMain.js

@@ -285,6 +285,7 @@ function getCodegenRunner(config: Config): CodegenRunner {
   const sourceWriterName = outputExtension;
   const sourceModuleParser = RelaySourceModuleParser(
     languagePlugin.findGraphQLTags,
+    languagePlugin.getFileFilter,
   );
   const providedArtifactDirectory = config.artifactDirectory;
   const artifactDirectory =

packages/relay-compiler/core/RelaySourceModuleParser.js

@@ -27,8 +27,10 @@ import type {FileFilter} from '../codegen/CodegenWatcher';
 import type {GraphQLTagFinder} from '../language/RelayLanguagePluginInterface';
 import type {DocumentNode} from 'graphql';
 
+export type GetFileFilter = (baseDir: string) => FileFilter;
+
 export type SourceModuleParser = {|
-  getFileFilter: (baseDir: string) => FileFilter,
+  getFileFilter: GetFileFilter,
   getParser: (baseDir: string) => ASTCache,
   parseFile: (baseDir: string, file: File) => ?DocumentNode,
   parseFileWithSources: (
@@ -42,7 +44,10 @@ export type SourceModuleParser = {|
 
 const parseGraphQL = Profiler.instrument(GraphQL.parse, 'GraphQL.parse');
 
-module.exports = (tagFinder: GraphQLTagFinder): SourceModuleParser => {
+module.exports = (
+  tagFinder: GraphQLTagFinder,
+  getFileFilter?: GetFileFilter,
+): SourceModuleParser => {
   const memoizedTagFinder = memoizedFind.bind(null, tagFinder);
 
   function parseFile(baseDir: string, file: File): ?DocumentNode {
@@ -104,7 +109,7 @@ module.exports = (tagFinder: GraphQLTagFinder): SourceModuleParser => {
     });
   }
 
-  function getFileFilter(baseDir: string): FileFilter {
+  function defaultGetFileFilter(baseDir: string): FileFilter {
     return (file: File) => {
       const filePath = path.join(baseDir, file.relPath);
       let text = '';
@@ -123,7 +128,7 @@ module.exports = (tagFinder: GraphQLTagFinder): SourceModuleParser => {
 
   return {
     getParser,
-    getFileFilter,
+    getFileFilter: getFileFilter ?? defaultGetFileFilter,
     parseFile,
     parseFileWithSources,
   };

packages/relay-compiler/language/RelayLanguagePluginInterface.js

@@ -20,6 +20,7 @@ import type {
 } from '../codegen/CodegenRunner';
 import type {IRTransform} from '../core/CompilerContext';
 import type {GeneratedDefinition, Root, Fragment} from '../core/IR';
+import type {GetFileFilter} from '../core/RelaySourceModuleParser';
 import type {Schema} from '../core/Schema';
 import type {ScalarTypeMapping} from './javascript/RelayFlowTypeTransformers';
 import type {GeneratedNode} from 'relay-runtime';
@@ -46,6 +47,7 @@ export type PluginInterface = {
   keepExtraFile?: KeepExtraFileFn,
   schemaExtensions?: $ReadOnlyArray<string>,
   getModuleName?: (operationName: string) => string,
+  getFileFilter?: GetFileFilter,
   ...
 };