Stop onActivityResult from proceeding when intent is null to prevent app from crashing

[AlgirdasVZ]

Partially fixes #130

Description

There are at least several cases where the app crashes in onActivityResult method when received data intent is null (more about this - #130). The cause of the crash is that AuthorizationResponse.fromIntent method (imported from net.openid.appauth) has a null checker method, which throws NullPointerException and the user is presented with a native crash info screen. I'm proposing to add a check for data intent being null, and terminate the authorization process if it is (reject the the promise with error message and return from onActivityResult method). As the data intent being null will always end up in crashing the app, there is no point to continue onActivityResult method. Terminating the authorization process instead would be much more user-friendly solution.

Steps to verify

One of the scenarios to reproduce the crash:

1. Open the app
2. Open the idp web login screen in the app
3. Put the app in background
4. Start the app from the device launcher

Prerequisites: android:launchMode="singleTask" in AndroidManifest.xml

[mklekowski]

Can it be released as a patch to 4.4.0?

[kadikraman]

Hi @mklekowski - I'd like to avoid maintaining two branches of the library - it'll get messy quick!

I'd use patch-package for this, since the change is so small:

1. open node_modules/react-native-app-auth/android/src/main/java/com/rnappauth/RNAppAuthModule.java and mirror the changes in this PR
2. run npx patch-package some-package (this will create a .patch file)
3. commit the patch to your source control
4. in package.json add a postistall script:

 "scripts": {
+  "postinstall": "patch-package"
 }

5. add the library as a dependency

yarn add patch-package postinstall-postinstall

or

npm i patch-package

This basically adds a patch to the library every time you do an install. Once you can upgrade to v5 of this library you can simply delete the patch file and the package.

[kadikraman]

Released in v5.0.0 🎉