message: Ensure that watchman returned a
diff: @@ -162,8 +162,14 @@ module.exports = async function watchmanCrawl(
  if (isOld) {
  files[name] = existingFileData;
  } else {
  + let sha1hex = fileData['content.sha1hex'];
  +
  + if (typeof sha1hex !== 'string' || sha1hex.length !== 40) {
  + sha1hex = null;
  + }
  +
  // See ../constants.js
  - files[name] = ['', mtime, 0, [], fileData['content.sha1hex'] || null];
  + files[name] = ['', mtime, 0, [], sha1hex];
  }
  }
  }
  