From d0fdca73cdfd4ca7e152d4c8a5d0bb616f336480 Mon Sep 17 00:00:00 2001
From: Rafael Oleza <rafeca@fb.com>
Date: Wed, 11 Apr 2018 09:41:32 -0700
Subject: [PATCH] metro-memory-fs: Do not report a file change when reading a
 file

Reviewed By: jeanlauliac

Differential Revision: D7584517

fbshipit-source-id: 55f87d15c723f697ea00c357da1d36f5d31accbb
---
 packages/metro-memory-fs/src/__tests__/index-test.js | 9 +++++++++
 packages/metro-memory-fs/src/index.js                | 4 +++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/packages/metro-memory-fs/src/__tests__/index-test.js b/packages/metro-memory-fs/src/__tests__/index-test.js
index 3781ff1f..6542d292 100644
--- a/packages/metro-memory-fs/src/__tests__/index-test.js
+++ b/packages/metro-memory-fs/src/__tests__/index-test.js
@@ -429,6 +429,15 @@ describe('watch', () => {
     watcher.close();
   });
 
+  it('does not report changes when just reading a file', () => {
+    const changedPaths = [];
+    fs.writeFileSync('/foo.txt', '');
+    const watcher = collectWatchEvents('/', {}, changedPaths);
+    fs.readFileSync('/foo.txt');
+    expect(changedPaths).toEqual([]);
+    watcher.close();
+  });
+
   function collectWatchEvents(entPath, options, events) {
     return fs.watch(entPath, options, (eventName, filePath) => {
       events.push([eventName, filePath]);
diff --git a/packages/metro-memory-fs/src/index.js b/packages/metro-memory-fs/src/index.js
index 3d7a5e2e..1497050e 100644
--- a/packages/metro-memory-fs/src/index.js
+++ b/packages/metro-memory-fs/src/index.js
@@ -197,7 +197,9 @@ class MemoryFs {
 
   closeSync = (fd: number): void => {
     const desc = this._getDesc(fd);
-    this._emitFileChange(desc.nodePath.slice(), {eventType: 'change'});
+    if (desc.writable) {
+      this._emitFileChange(desc.nodePath.slice(), {eventType: 'change'});
+    }
     this._fds.delete(fd);
   };