Change FeatureFlagService.isFeatureEnabled return value from Boolean to Flow<Boolean> #1703

bmarty · 2023-10-31T10:45:05Z

Type of change

Feature
Bugfix
Technical
Other :

Content

Change FeatureFlagService.isFeatureEnabled return value from Boolean to Flow

Motivation and context

Be able to have "live" behavior of feature flag. Until now this was not necessary because when user goes to the settings to switch a flag, the flag is read again when entering the screen where the flag has an effect. Ex: Timeline.

But without this, it would be a bit harder (yet not impossible) to have a flag that have effect on the room list for instance, since the settings screen is a subscreen of the room list.

In particular, we will need this to be able to add a feature flag for the key backup. A banner can be displayed on the room list.

Screenshots / GIFs

NA

Tests

Play with the feature flags and check that the effect are still working as expected.

Tested devices

Physical
Emulator
OS version(s):

Checklist

Changes have been tested on an Android device or Android emulator with API 23
UI change has been tested on both light and dark themes
Accessibility has been taken into account. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
Pull request is based on the develop branch
Pull request includes a new file under ./changelog.d. See https://github.com/vector-im/element-x-android/blob/develop/CONTRIBUTING.md#changelog
Pull request includes screenshots or videos if containing UI changes
Pull request includes a sign off
You've made a self review of your PR

bmarty · 2023-10-31T10:45:35Z

...eflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlagService.kt

@@ -33,3 +36,6 @@ interface FeatureFlagService {
     */
    suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean): Boolean
 }
+
+suspend fun FeatureFlagService.isFeatureEnabled(feature: Feature): Boolean =


Adding a handy extension to avoid touching the code too much.

github-actions · 2023-10-31T11:03:15Z

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julioromano · 2023-10-31T12:55:24Z

...l/src/main/kotlin/io/element/android/libraries/featureflag/impl/StaticFeatureFlagProvider.kt

-    override suspend fun isFeatureEnabled(feature: Feature): Boolean {
-        return if (feature is FeatureFlags) {
-            when(feature) {
+    override suspend fun isFeatureEnabledFlow(feature: Feature): Flow<Boolean> {


suspend here shall be removed

Yes, updated.

julioromano · 2023-10-31T12:56:59Z

...eflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlagService.kt

@@ -33,3 +36,6 @@ interface FeatureFlagService {
     */
    suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean): Boolean
 }
+
+suspend fun FeatureFlagService.isFeatureEnabled(feature: Feature): Boolean =


This makes it a breaking change.
If you kept this API as it was and added the flow variant to the interface, it would be an "addition only change" and hence non-breaking.