[Feature Proposal]Property Wrapper for RemoteConfig

[fumito-ito]

Why

#9828

What

This PR provides a Property Wrapper with DynamicProperty for RemoteConfig. With this feature, users can bind Remote Config values to variables, and at the same time, reflect them in the View of the SwiftUI in real time.

Known Issues

• The lastFetchTime is monitored to detect that the RemoteConfig value has changed. This is not very accurate. For example, if the defaultValue is changed, the change will not be detected.
• Only Decodable properties are covered. Therefore, users cannot bind the PropertyWrapper to variables of type Any, such as those provided by jsonValue.

[morganchen12]

Thanks for the feature proposal implementation! We'll have to get this through internal API review, but at a glance this looks good to me.

[paulb777]

Thanks @fumito-ito! Please resolve the CI issues.

[fumito-ito]

CI back to green 🙌

[paulb777]

Thanks for working through the CI issues!

[paulb777]

Please add the "subsequent" test to show the contrast or do you want to compare to the tests in Value.swift?

[fumito-ito]

Sorry, This is the code comment I copied and forgot to delete. I will erase it.

[fumito-ito]

(done)

[paulb777]

Thanks! We need to do an internal API review process so it may take us a few weeks to a month to merge, but I expect it to happen.

[charlotteliang]

@fumito-ito Thank you for this initiative! I'm looking into the API review right now. Do you have a sample test app or some sample code that I can see how to use this new API to reflect config changes on SwiftUI?

[fumito-ito]

Hi! @chliangGoogle thank you for your feedback. The simplest sample is like #9828.

@RemoteConfig(forKey: "is_new_feature_available")
var isNewFeatureAvailable: Bool

Toggle(isOn: isNewFeatureAvailable) {
     Text("wonderful new feature")
}

If you need more sample app, I can upload it into the repository but I cannot find where to put sample apps for remote config. Could you tell me place for sample app ?

[charlotteliang]

@fumito-ito The sample code is exactly what I need. No need to make a sample app for this. Thanks!

[charlotteliang]

@fumito-ito I believe this should be triggered when developer calls fetchAndActivate API because last fetch time changed (for a fresh install), is that correct? However, it's not called for me when I test it out.

[fumito-ito]

@chliangGoogle thanks for your review. I found observing lastFetcheTime is not working.

There are following options for this PR. How do you feel about these options ?

• convert to simple property wrapper, not dynamic property
  • It's not fit for my needs (Remote Config working with SwiftUI)
• propagate last fetch time changes from RCNUserDefaultsManager
  • It may be possible, but I need time for this change (I'm not familiar to Objective-C)

[charlotteliang]

Hey @fumito-ito I'm working on Google Open Source Peer Bonus nominations and would like to recognize your contribution to make Firebase Remote Config more SwiftUI friendly. I couldn't find an email address for you, so if you're interested, please email it to chliang at google.com and I'll make the nomination.

[mdeaconu]

Small typo.

[paulb777]

Going to close since this PR was incorporated into #10155.

Thanks @fumito-ito for getting this going!