From 18287c226291df88fb1518d184d5838455515ce7 Mon Sep 17 00:00:00 2001
From: vahid torkaman <vahidt@spotify.com>
Date: Tue, 23 Jan 2024 17:46:02 +0100
Subject: [PATCH] map to empty stream in case of setting provider to nil

Signed-off-by: vahid torkaman <vahidt@spotify.com>
---
 Sources/OpenFeature/EventHandler.swift             |  6 +++---
 Sources/OpenFeature/OpenFeatureAPI.swift           | 14 +++++++++++---
 Sources/OpenFeature/Provider/NoOpProvider.swift    |  2 +-
 .../DeveloperExperienceTests.swift                 |  4 +++-
 .../Helpers/AlwaysBrokenProvider.swift             |  2 +-
 .../Helpers/DoSomethingProvider.swift              |  2 +-
 6 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/Sources/OpenFeature/EventHandler.swift b/Sources/OpenFeature/EventHandler.swift
index dad6388..f1a5680 100644
--- a/Sources/OpenFeature/EventHandler.swift
+++ b/Sources/OpenFeature/EventHandler.swift
@@ -8,8 +8,8 @@ public class EventHandler: EventSender, EventPublisher {
         eventState = CurrentValueSubject<ProviderEvent, Never>(ProviderEvent.stale)
     }
 
-    public func observe() -> CurrentValueSubject<ProviderEvent, Never> {
-        return eventState
+    public func observe() -> AnyPublisher<ProviderEvent, Never> {
+        return eventState.eraseToAnyPublisher()
     }
 
     public func send(
@@ -20,7 +20,7 @@ public class EventHandler: EventSender, EventPublisher {
 }
 
 public protocol EventPublisher {
-    func observe() -> CurrentValueSubject<ProviderEvent, Never>
+    func observe() -> AnyPublisher<ProviderEvent, Never>
 }
 
 public protocol EventSender {
diff --git a/Sources/OpenFeature/OpenFeatureAPI.swift b/Sources/OpenFeature/OpenFeatureAPI.swift
index ec18e86..8e0c2fc 100644
--- a/Sources/OpenFeature/OpenFeatureAPI.swift
+++ b/Sources/OpenFeature/OpenFeatureAPI.swift
@@ -73,11 +73,19 @@ public class OpenFeatureAPI {
         self.hooks.removeAll()
     }
 
-    public func observe() -> any Publisher<ProviderEvent, Never> {
+    public func observe() -> AnyPublisher<ProviderEvent, Never> {
         return providerSubject
-            .compactMap{ $0 }
-            .map({ provider in provider.observe()})
+            .map({ provider in
+                if let provider = provider {
+                    return provider.observe()
+                } else {
+                    return Empty<ProviderEvent, Never>()
+                        .eraseToAnyPublisher()
+                }
+            })
             .switchToLatest()
+            .eraseToAnyPublisher()
+
     }
 
     struct Handler {
diff --git a/Sources/OpenFeature/Provider/NoOpProvider.swift b/Sources/OpenFeature/Provider/NoOpProvider.swift
index 858228e..6f35cbc 100644
--- a/Sources/OpenFeature/Provider/NoOpProvider.swift
+++ b/Sources/OpenFeature/Provider/NoOpProvider.swift
@@ -67,7 +67,7 @@ class NoOpProvider: FeatureProvider {
             value: defaultValue, variant: NoOpProvider.passedInDefault, reason: Reason.defaultReason.rawValue)
     }
 
-    func observe() -> CurrentValueSubject<ProviderEvent, Never> {
+    func observe() -> AnyPublisher<ProviderEvent, Never> {
         return eventHandler.observe()
     }
 }
diff --git a/Tests/OpenFeatureTests/DeveloperExperienceTests.swift b/Tests/OpenFeatureTests/DeveloperExperienceTests.swift
index ac4d500..f43b957 100644
--- a/Tests/OpenFeatureTests/DeveloperExperienceTests.swift
+++ b/Tests/OpenFeatureTests/DeveloperExperienceTests.swift
@@ -39,11 +39,13 @@ final class DeveloperExperienceTests: XCTestCase {
         OpenFeatureAPI.shared.setProvider(provider: provider)
         wait(for: [readyExpectation], timeout: 5)
 
+        OpenFeatureAPI.shared.clearProvider()
+
         // Clearing the Provider shouldn't send further global events from it
         eventState = OpenFeatureAPI.shared.observe().sink { _ in
             XCTFail("Unexpected event")
         }
-        OpenFeatureAPI.shared.clearProvider()
+
         provider.initialize(initialContext: MutableContext(attributes: ["Test": Value.string("Test")]))
 
         XCTAssertNotNil(eventState)
diff --git a/Tests/OpenFeatureTests/Helpers/AlwaysBrokenProvider.swift b/Tests/OpenFeatureTests/Helpers/AlwaysBrokenProvider.swift
index ecefc8d..f660e7a 100644
--- a/Tests/OpenFeatureTests/Helpers/AlwaysBrokenProvider.swift
+++ b/Tests/OpenFeatureTests/Helpers/AlwaysBrokenProvider.swift
@@ -46,7 +46,7 @@ class AlwaysBrokenProvider: FeatureProvider {
         throw OpenFeatureError.flagNotFoundError(key: key)
     }
 
-    func observe() -> CurrentValueSubject<ProviderEvent, Never> {
+    func observe() -> AnyPublisher<ProviderEvent, Never> {
         eventHandler.observe()
     }
 }
diff --git a/Tests/OpenFeatureTests/Helpers/DoSomethingProvider.swift b/Tests/OpenFeatureTests/Helpers/DoSomethingProvider.swift
index 444a0e5..c58a4e2 100644
--- a/Tests/OpenFeatureTests/Helpers/DoSomethingProvider.swift
+++ b/Tests/OpenFeatureTests/Helpers/DoSomethingProvider.swift
@@ -58,7 +58,7 @@ class DoSomethingProvider: FeatureProvider {
         return ProviderEvaluation(value: .null)
     }
 
-    func observe() -> CurrentValueSubject<ProviderEvent, Never> {
+    func observe() -> AnyPublisher<ProviderEvent, Never> {
         eventHandler.observe()
     }