React Native Packager TypeError: Cannot read property ‘root’ of null

While working on Find&Save‘s Cash Dash Inbox feature which is built using React Native I started the node packager and launched the app into SIM but got this error as soon as the app attempted to load the bundle:

TypeError: Cannot read property 'root' of null

Turns out the issue was an outdated watchman. Ok so off to brew update

stevet:iPhoneGeo strefethen$ brew update
Error: undefined method `link_overwrite' for #<Class:0x007fdb697392d0>

Doh! Looks like I ran into a “hole not many people should fall into“. Anyhoo, as suggested let’s try that again:

stevet:iPhoneGeo strefethen$ brew update
Already up-to-date.
stevet:iPhoneGeo strefethen$ brew upgrade watchman
==> Upgrading 1 outdated package, with result:
watchman 3.7.0
==> Upgrading watchman
==> Downloading https://homebrew.bintray.com/bottles/watchman-3.7.0.yosemite.bottl
######################################################################## 100.0%
==> Pouring watchman-3.7.0.yosemite.bottle.tar.gz
🍺  /usr/local/Cellar/watchman/3.7.0: 9 files, 240K

Whala now the packager is happy again. Btw, another Engineer on my team had this same problem and her machine required a reboot before things started working again.

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Steve

Husband, father, brother, software developer. CTO @WanderfulMedia