New bundled expo-cli start is returning a manifest that cannot be parsed by expo-dev-launcher

SDK Version: 47
Platforms(Android/iOS/web/all): Android

We are currently going through the upgrade from expo SDK 45 from 47. Part of the upgrade to 46 involves the recommended switch to using the bundled expo-cli, rather than the global instance.

When we make this change, and run npx expo start --dev-client, our android app throws an error when selecting the dev server, with the message:

Value ----------------------------224819657222108214122421 of type java.lang.String cannot be converted to JSONObject

When I hit the dev server url (eg. manually to obtain the manifest, I can see it is indeed starting with the above value, as it contains some meta-data, eg.

Content-Disposition: form-data; name="manifest"
Content-Type: application/json


When I switch back to using the globally installed CLI as per the instructions in the upgrade blog (so changing the start command from npx expo start to expo-cli start), the same test results in the manifest being returned without the supplementary data, and the app can be loaded successfully.

I also have this problem, it also happens for me when I don’t use the --dev-client option.

I seem to have solved it for me. Seemingly it is related to expo-upates. After removing it and all accompanying configuration and reinstalling the npm modules my manifest is back to normal.

Just so you can replicate my testing steps:
I created a new expo-project, copied the code and package*.json into the new project installed the missing modules except expo-updates and then it started as usual.

Maybe this works for you as well!