Initial Feature Flags Support

[jaredmixpanel]

This PR adds initial support for using Mixpanel Feature Flags to the Android SDK. As part of this work we introduce the MixpanelOptions object to encapsulate all optional initialization parameters, i.e. instanceName, optOutTrackingDefault, superProperties, featureFlagsEnabled and featureFlagsContext... in order to avoid further constructor and getInstance signature proliferation. All of the existing signatures will be supported for backwards compatibility by ultimately building a MixpanelOptions object to be passed into the new canonical/designated constructor which expects a MixpanelOptions instance.

Example usage (in Kotlin, note that Kotlin automatically converts Java getters like getFlags() into properties like flags):

val flagsContext = JSONObject()
flagsContext.put("my_context_key", "my_context_value")
val mpOptionsBuilder = MixpanelOptions.Builder().featureFlagsEnabled(true).featureFlagsContext(flagsContext)
val mpOptions = mpOptionsBuilder.build()
val mixpanel = MixpanelAPI.getInstance(context, MIXPANEL_PROJECT_TOKEN, true, mpOptions)
mixpanel.flags.loadFlags()  // called automatically during SDK initialization
val ready = mixpanel.flags.areFlagsReady()
if (ready) {
    val featureFlagData = mixpanel.flags.getVariantSync(featureName, fallback)
}
mixpanel.flags.getVariant(featureName, fallback,
    FlagCompletionCallback { result -> 
        println("Key: ${result.key}")
        println("Value: ${result.value}")
    }
)
if (mixpanel.flags.areFlagsReady()) {
    val value = mixpanel.flags.getVariantValueSync(featureName, fallbackValue)
}
mixpanel.flags.getVariantValue(featureName, fallbackValue,
    FlagCompletionCallback { value -> 
        println("Value: $value")
    }
)
if (mixpanel.flags.areFlagsReady()) {
    val isEnabled = mixpanel.flags.isFlagEnabledSync(featureName, fallbackValue)
}
mixpanel.flags.isFlagEnabled(featureName, fallbackValue,
    FlagCompletionCallback { isEnabled -> 
        println("Is Enabled: $isEnabled")
    }
)

[Copilot]

Pull Request Overview

This PR introduces initial support for feature flags in the Mixpanel Android SDK along with several API enhancements and configuration updates.

• Adds new parameters and method documentation in RemoteService and HttpService for handling feature flags and raw request bodies.
• Introduces feature flag parsing in JsonUtils, new configuration classes (FlagsConfig, FeatureFlagData), and integrates feature flag management in MixpanelAPI and MPConfig.
• Updates tests and demo code to work with the new flags functionality.

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/main/java/com/mixpanel/android/util/RemoteService.java	Updated performRequest method with extended parameters and added detailed Javadoc.
src/main/java/com/mixpanel/android/util/MPConstants.java	Added FLAG endpoint constant for feature flags.
src/main/java/com/mixpanel/android/util/JsonUtils.java	Enhanced JSON parsing for feature flags responses.
src/main/java/com/mixpanel/android/util/HttpService.java	Revised HTTP request handling to support both URL-encoded and raw request body with custom headers.
src/main/java/com/mixpanel/android/mpmetrics/MixpanelOptions.java	Integrated feature flag options in MixpanelOptions builder.
src/main/java/com/mixpanel/android/mpmetrics/MixpanelAPI.java	Integrated the feature flag manager and added feature flag API methods.
src/main/java/com/mixpanel/android/mpmetrics/MPConfig.java	Added support for flags endpoint configuration.
src/main/java/com/mixpanel/android/mpmetrics/FlagsConfig.java	New configuration class for feature flags.
src/main/java/com/mixpanel/android/mpmetrics/FeatureFlagData.java	Added data class for representing feature flag data.
Other test and demo files	Updated to work with changes in HTTP and feature flag API methods.

Comments suppressed due to low confidence (1)

src/main/java/com/mixpanel/android/mpmetrics/FeatureFlagData.java:18

• In the fallback constructor, 'this.value' is mistakenly set to 'key' instead of null. Consider changing it to 'this.value = null;' to correctly reflect a missing value.

public FeatureFlagData(@NonNull String key) { this.key = key; this.value = key; // Defaulting value to null if not provided }

[Copilot]

Pull Request Overview

This PR introduces initial support for feature flags into the Mixpanel Android SDK along with a new options builder and configuration settings. Key changes include:

• Enhancements to HTTP request handling in RemoteService and HttpService (support for headers and raw body).
• Additions for feature flags handling via new APIs, configurations, and associated models (MixpanelOptions, MPConfig, FlagsConfig, FeatureFlagData, FlagCompletionCallback).
• Updates to tests and demo code to support the new feature flags interfaces and a minor Gradle wrapper upgrade.

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/main/java/com/mixpanel/android/util/RemoteService.java	Updated performRequest API with additional parameters and documentation.
src/main/java/com/mixpanel/android/util/MPConstants.java	Added endpoints and key constants for feature flags.
src/main/java/com/mixpanel/android/util/JsonUtils.java	Added helper method for parsing feature flags JSON response.
src/main/java/com/mixpanel/android/util/HttpService.java	Updated performRequest signature and improved error handling with additional logging.
src/main/java/com/mixpanel/android/mpmetrics/MixpanelOptions.java	Introduced new options for toggling feature flags support and context.
src/main/java/com/mixpanel/android/mpmetrics/MixpanelAPI.java	Integrated feature flags load and access methods into the API.
src/main/java/com/mixpanel/android/mpmetrics/MPConfig.java	Added support for configuring flags endpoint.
src/main/java/com/mixpanel/android/mpmetrics/FlagsConfig.java	Added a configuration class for feature flags.
src/main/java/com/mixpanel/android/mpmetrics/FeatureFlagData.java	Added model class representing feature flag data.
Other test and demo files	Updated mocks and demo interactions to use the new performRequest signature and feature flag APIs.
gradle/wrapper/gradle-wrapper.properties	Updated Gradle wrapper version for compatibility.

[Copilot]

Pull Request Overview

This pull request implements initial support for feature flags in the Mixpanel Android SDK and updates various network and configuration components accordingly. Key changes include:

• Extending network operations with additional parameters (e.g. headers and raw body support) and updated documentation.
• Adding new classes and interfaces for feature flag management (FeatureFlagData, Flags, FlagCompletionCallback) along with relevant API methods.
• Updating configuration (MPConfig) and sample/test code to integrate feature flag support and endpoint settings.

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/main/java/com/mixpanel/android/util/RemoteService.java	Updated interface with expanded performRequest signature and thorough Javadoc documentation.
src/main/java/com/mixpanel/android/util/HttpService.java	Refactored performRequest with additional parameters and enhanced error reporting and resource cleanup.
src/main/java/com/mixpanel/android/mpmetrics/MixpanelAPI.java	Adjusted instantiation and API overloads to pass MixpanelOptions for feature flags.
src/main/java/com/mixpanel/android/mpmetrics/MPConfig.java	Added settings for FlagsEndpoint and updated endpoint URLs accordingly.
Other files (tests, demo, utility classes)	Updated to use the new API signature and integrate feature flags throughout the codebase.