Update demo app Clients from lateinit vars to nullable vars

[tdchow]

Summary of changes

• Convert Clients from a lateinit var to a nullable var in the demo app for card and PayPal web flows

There were crashes in the demo app where lateinit Clients were not getting set either due to a network error or if the activity was cleared without setting the client. These crashes were introduced when the removeObservers() function was added to the clients.

Checklist

• Added a changelog entry

Authors

List GitHub usernames for everyone who contributed to this pull request.

[sarahkoop]

These errors are specific to our demo app integration right? I don't quite understand what in the removeObservers method would cause clients to be set to null - but wondering if this would impact merchant integrations too

[tdchow]

These errors are specific to our demo app integration right? I don't quite understand what in the removeObservers method would cause clients to be set to null - but wondering if this would impact merchant integrations too

Yep, these are crashes due to how the demo app's ViewModels declare the client instances as lateinit. If the ViewModel never sets the Client and the Activity is cleared, kotlin.UninitializedPropertyAccessException: lateinit property cardClient has not been initialized is thrown, when removeObservers() is called on an uninitialized client object.

If merchants followed this pattern in their integration, they'd also need to convert from a lateinit var to a nullable var.

[sarahkoop]

These errors are specific to our demo app integration right? I don't quite understand what in the removeObservers method would cause clients to be set to null - but wondering if this would impact merchant integrations too

Yep, these are crashes due to how the demo app's ViewModels declare the client instances as lateinit. If the ViewModel never sets the Client and the Activity is cleared, kotlin.UninitializedPropertyAccessException: lateinit property cardClient has not been initialized is thrown, when removeObservers() is called on an uninitialized client object.

If merchants followed this pattern in their integration, they'd also need to convert from a lateinit var to a nullable var.

Should we add more docs to the removeObservers method to call this out? This only applies if merchants start using that method correct? (trying to confirm it's not a breaking change)

[tdchow]

These errors are specific to our demo app integration right? I don't quite understand what in the removeObservers method would cause clients to be set to null - but wondering if this would impact merchant integrations too

Yep, these are crashes due to how the demo app's ViewModels declare the client instances as lateinit. If the ViewModel never sets the Client and the Activity is cleared, kotlin.UninitializedPropertyAccessException: lateinit property cardClient has not been initialized is thrown, when removeObservers() is called on an uninitialized client object.
If merchants followed this pattern in their integration, they'd also need to convert from a lateinit var to a nullable var.

Should we add more docs to the removeObservers method to call this out? This only applies if merchants start using that method correct? (trying to confirm it's not a breaking change)

Yeah, I think we can call this out in the devdocs. Have we already made initial updates to the devdocs to add this function?

I wouldn't call this a breaking change since the merchant owns the instantiation and management of the client instances.