Follow-up to adding a Podspec

Once https://github.com/realm/realm-js/pull/2586 merge, we still have a few outstanding changes to the codebase and docs:

• Remove the hint about running “react-native link realm”.
• Read CONTRIBUTING.md to ensure nothing is outdated and write https://github.com/realm/realm-js/blob/master/CONTRIBUTING.md#how-to-debug-react-native-podspec
• Update docs to ensure it’s not mentioning running “react-native link realm”, including instructions to manually link.
• ~Run “pod lib lint --verbose” on CI (from node_modules/realm of a React Native app)~ As we pod install in the integration tests, this is probably not needed.
• Write about the caveats of the “use_frameworks!” support.
• Consider using a global to make Realm JS depend on the React framework, instead of reading the users Podfile (which is a hack).
• GCDWebServer is now a CocoaPod dependency and since Android uses NanoHttpd we can remove the GCDWebServer submodule from the repository.
• Depend on a specific major version of GCDWebServer.
• Investigate if we could provide a way of building Realm JS with the debug version of the shared library.
• Update the example app by unlinking Realm JS.
• Setup an install test on CI (with and without use_frameworks! - see https://blog.cocoapods.org/CocoaPods-0.36/).

[davidnuvolar]

@ioveracker found the root cause of the issue! If you just care about the solution, upgrading your realm dependency to 3.6.0 should fix this. It was fixed in this PR https://github.com/realm/realm-js/pull/2623/

If someone is curious and wants to know more: What is the checksum we see in the Podfile.lock? It is just the SHA1 from the Podfile.lock.json You can get the hash by running from the command line: cat /path/to/your/react-native/project/ios/Pods/Local\ Podspecs/RealmJS.podspec.json | openssl sha1

So if different computers are producing different hashes, it means the content of that json file must be different. That’s exactly what’s happening here. In the Podspec from version 3.4.2, line 78, https://github.com/realm/realm-js/blob/6e28389898a6276459b95e1c861a4166e87a69d0/RealmJS.podspec#L78 the code generates an absolute path when building your local json podspec. Because of this, different computers with the project in different locations will generate different checksum for this pod.

In version 3.6.0 this has been changed to https://github.com/realm/realm-js/blob/13a6fc834a656c1d0551fea3ca82318aa61fb28e/RealmJS.podspec#L86 and now it uses an environment variable. Because of this, the checksum will match even if the location of the project is different.

[kraenhansen]

Awesome @davidnuvolar! Thanks for getting to the bottom of this, its a nice side-effect of not having absolute paths produced by the Podspec.