Encrypted features are not being restored from disk cache

[midery]

Hello! We recently discovered an issue with GrowthBook Android SDK:

When we use encryption and save encrypted features to a disk cache, they're not being restored from it. This happens in FeaturesViewModel.fetchFeatures method: only dataModel.features is being restored, but dataModel.encryptedFeatures is being ignored.

This results in incorrect state if we read some values right after app start, before we fetch the updated value from a remote.

Reproducible steps:

1. Use encryptionKey when initializing GrowthbookSDK
2. Run your application once to fetch the data and save this data on disk.
3. Try to read feature value right after initialization

Expected behavior:
GrowthbookSDK.getFeatures() returns previously fetched features, feature's source is the source from last remote call.
Actual behavior:
GrowthbookSDK.getFeatures() returns empty map, feature's source is "unknownFeature"

Is this an intentional behavior? If it is not, can you please take a look into it? 🙏

[Bohdan-Kim]

Hello @midery!
Thanks for reporting this. Could you please specify SDK version you found this issue on?

[midery]

@Bohdan-Kim hello! Thanks for a swift reply!

We use version 1.1.43. But as far as I can see, it should persist even on latest 1.1.47, as the code snippet for restoring features from cache was not updated.

[Bohdan-Kim]

The encrypted features are transferred over the network while you are always pointing us to the restoring features from cache. I would agree if it will be encrypted features from Backend but you are pointing to the features from cache.

[Bohdan-Kim]

Could you please try to reproduce on 1.1.47 version? There should be Fix encrypted features preparation

[midery]

The encrypted features are transferred over the network while you are always pointing us to the restoring features from cache. I would agree if it will be encrypted features from Backend but you are pointing to the features from cache.

Yeah, you're absolutely right!
The problem that we currently encryptedFeatures are being saved to the disk (reference is here), but not being restored from disk (reference is here: we only restore dataModel.features, while dataModel.encryptedFeatures are being ignored).

Because of that, even if users are loaded encryptedFeatures previously, they won't be able to take these from cache, and would need to wait until the backend response.

Could you please try to reproduce on 1.1.47 version? There should be #94

Thanks, I'll try this version and report here!

[Bohdan-Kim]

We need to investigate it a little bit deeper

[Bohdan-Kim]

The pull request was created according to this issue.