Xcode: on deploy to device, Packager re-packages even when no changes

Description

Sometimes I use Xcode to deploy my RN app to a physical device using the Xcode toolbar, e.g.

As expected, during the ‘Bundle React Native code and images’ build phase…

…the RN Packager bundles the app. It’s a substantially lengthy process, in my case ~6-8 minutes.

If I don’t change any code and simply deploy the app again using Xcode, the entire packager build restarts.

Is there a way I can persist Packager builds across Xcode deploys?

Feels like the whole point of HMR/Live Reload is to avoid this – how can I bring it to device deploys? Given how clever HMR is, this just seems so unnecessary.

Reproduction

1. Open an RN project’s ios/app.xcodeproj
2. Plug in physical iOS device
3. Deploy RN app to device
4. Don’t change any code
5. Deploy again

Additional Information

• React Native version: 0.33
• Xcode version: 8.1
• Platform: iOS
• Operating System: MacOS El Capitan 10.11.6

Did an Issues search for ‘Xcode’ & ‘Xcode Packager’ – didn’t find anything pertinent, apologies if this is a dupe.

[ephemer]

@frantic I appreciate the tip. If I didn’t need anything built I could also just tap the app on the device’s springboard.

What about the case where you’re developing a native plugin which requires constant rebuilding of native code but not of the JS bundle?

It’s possible to work around this (to a degree) by creating a new RN project containing only the component under development, but this involves a fair bit of overhead, including maintenance of an additional project.

To me it’d make sense to have some intelligent way around this built into the tooling, without the overhead. For example, would it be reasonable to at least do the JS build in parallel to the native build instead of in series? I don’t fully understand the bundler yet but from what I gather it shouldn’t matter - in debug / development - whether the app starts before the bundling is complete

[pvinis]

yea this should change. i propose we change the react-native-xcode.sh code, to skip building if its the scheme is Debug. currently it skips if the scheme is Debug AND its running on a simulator. Debugging should be quick and not build the bundle, even on a device.