Crash while yarn upgrade

[qkdreyer]

1. Start wml after at least a link has been added
2. Run yarn global upgrade

Stack trace :

events.js:136
      throw er; // Unhandled 'error' event
      ^

TypeError: Cannot read property 'src' of undefined
    at updateWatchers (/Users/qkdreyer/.config/yarn/global/node_modules/wml/src/cli/start.js:143:33)
    at onLinksChange (/Users/qkdreyer/.config/yarn/global/node_modules/wml/src/cli/start.js:27:3)
    at Client.<anonymous> (/Users/qkdreyer/.config/yarn/global/node_modules/wml/src/subscribe.js:38:11)
    at Client.emit (events.js:159:13)
    at BunserBuf.<anonymous> (/Users/qkdreyer/.config/yarn/global/node_modules/fb-watchman/index.js:90:14)
    at BunserBuf.emit (events.js:159:13)
    at BunserBuf.process (/Users/qkdreyer/.config/yarn/global/node_modules/bser/index.js:289:10)
    at /Users/qkdreyer/.config/yarn/global/node_modules/bser/index.js:244:12
    at _combinedTickCallback (internal/process/next_tick.js:131:7)
    at process._tickCallback (internal/process/next_tick.js:180:9)