Ignore watchmanconfig in fbsource (#868)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/868

As discussed in D20252170

Reviewed By: passy

Differential Revision: D20278783

fbshipit-source-id: c965520a0ad44bf1838224003017177c149025e9

.gitignore

@@ -4,6 +4,9 @@ website/build
 yarn-error.log
 static/main.bundle.*
 
+# conflicts with FB internal infra
+.watchmanconfig
+
 # iOS / Xcode
 *.xcworkspace
 **/Pods/

scripts/yarn-install.ts

@@ -11,8 +11,10 @@ import path from 'path';
 import util from 'util';
 import globImport from 'glob';
 import {exec as execImport} from 'child_process';
+import {exists as existsImport, copyFile} from 'fs';
 const glob = util.promisify(globImport);
 const exec = util.promisify(execImport);
+const exists = util.promisify(existsImport);
 const PACKAGES = [
   'headless-tests',
   'static',
@@ -26,6 +28,9 @@ const YARN_PATH =
     ? path.join(__dirname, process.argv[2])
     : 'yarn' + (WINDOWS ? '.cmd' : '');
 
+prepareWatchmanConfig(path.join(__dirname, '..'));
+prepareWatchmanConfig(path.join(__dirname, '..', 'static'));
+
 Promise.all(
   PACKAGES.map(pattern =>
     glob(path.join(__dirname, '..', pattern, 'package.json')),
@@ -63,3 +68,15 @@ Promise.all(
     console.error(err);
     process.exit(1);
   });
+
+async function prepareWatchmanConfig(dir: string) {
+  const hasGit = exists(path.join(__dirname, '..', '.git'));
+  const hasWatchmanConfig = exists(path.join(dir, '.watchmanconfig'));
+  if ((await hasGit) && !(await hasWatchmanConfig)) {
+    console.log(`Creating .watchmanconfig in ${dir}`);
+    await util.promisify(copyFile)(
+      path.join(dir, '_watchmanconfig'),
+      path.join(dir, '.watchmanconfig'),
+    );
+  }
+}

static/.watchmanconfig

@@ -1 +0,0 @@
-{}

static/_watchmanconfig

@@ -0,0 +1,3 @@
+{
+  "ignore_dirs": ["node_modules"]
+}