Unleash / unleash-android / 38719019292

84%

Build Type

push

github

Committed by web-flow

Commit Message

fix: scope `close()` to the instance instead of the whole process (#152)

fix: scope close() to the instance instead of the whole process

## Issue
Working at [OF-provider issue with start()](https://github.com/Unleash/unleash-openfeature-android-provider/pull/4), we noticed that:

`unleash-openfeature-android-provider` calls `close()` from its `shutdown()` ...but
when we create an Unleash client, close it, then create another one. The 2nd client **never** works - no flags, no fetching, no error. Every lookup returns the fallback value ..._forever_.

e.g.
```kotlin
val first = DefaultUnleash(context, config)
first.start()
first.close()

val second = DefaultUnleash(context, config)
second.start()
// second.isReady() is false, and stays false. No exception. Nothing in logcat.
```

#### Whom affects? 
anything that creates a client, closes it, and creates another one in the same process:
- apps that re-initialise on logout/login.
- providers like `unleash-openfeature-android-provider` which calls `close()` from its `shutdown()`.
- test suites that set up and tear down per test. The 2nd test onwards silently gets a dead client.


### Why it happens

the SDK has exactly one Job for the entire app:
```kotlin
// DefaultUnleash.kt
private val job = SupervisorJob()
val unleashScope = CoroutineScope(Dispatchers.Default + job + unleashExceptionHandler)
```

there is one instance of it per process, shared by every client the SDK creates. And `close()` ends with:

```kotlin
job.cancel("Unleash received closed signal")
```

So **closing one client** **flips the whole library**. The 1st client shut down correctly - but so did the Job _every_ future client depends on.

That's why the 2nd client fails silently rather than crashing: `start()` calls `coroutineScope.launch { readyOnFeaturesReceived() }`, the launch is a no-op on a cancelled Job, so nothing fetches, nothing lands in the cache, `ready` is always 'unknown' :/ 

## The fix

We now give each client its own Jo... (continued)

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