fix: improved LDClient.identify(...) behavior when offline (#261)

**Requirements**

- [x] I have added test coverage for new or changed functionality

- [x] I have followed the repository's [pull request submission
guidelines](../blob/main/CONTRIBUTING.md#submitting-pull-requests)
- [x] I have validated my changes against all supported platform
versions

**Related issues**

SC-237349

**Describe the solution you've provided**

Updated code so that ContextDataManager switches context independently
of ConnectivityManager and ConnectivityManager is not in the path of
context switching.

launchdarkly-android-client-sdk/src/androidTest/java/com/launchdarkly/sdk/android/LDClientEndToEndTest.java

@@ -144,4 +144,38 @@ public void clientUsesStoredFlagsIfInitializationTimesOutInPollingMode() throws
             assertEquals(flagValue, client.stringVariation(flagKey, "default"));
         }
     }
+
+    @Test
+    public void identifyWhenPollingFailsAndCacheAlreadyExists() throws Exception {
+        // set up data store with flag data for ContextA and ContextB
+        // insert ContextA's flags
+        LDContext contextA = LDContext.create("ContextA");
+        String flagKeyA = "flag-keyA", flagValueA = "stored-valueA";
+        Flag flagA = new FlagBuilder(flagKeyA).version(1).value(LDValue.of(flagValueA)).build();
+        TestUtil.writeFlagUpdateToStore(store, MOBILE_KEY, contextA, flagA);
+        // insert contextB's flags
+        LDContext contextB = LDContext.create("ContextB");
+        String flagKeyB = "flag-keyB", flagValueB = "stored-valueB";
+        Flag flagB = new FlagBuilder(flagKeyB).version(1).value(LDValue.of(flagValueB)).build();
+        TestUtil.writeFlagUpdateToStore(store, MOBILE_KEY, contextB, flagB);
+
+        // response to initialization for ContextA
+        mockPollingServer.enqueue(new MockResponse().setResponseCode(401));
+
+        // response to contextB's identify
+        mockPollingServer.enqueue(new MockResponse().setResponseCode(401));
+
+        LDConfig config = baseConfig()
+                .dataSource(Components.pollingDataSource())
+                .serviceEndpoints(Components.serviceEndpoints().polling(mockPollingServerUri))
+                .build();
+
+        LDClient client = LDClient.init(application, config, contextA, 1);
+        assertFalse("client should not have been initialized", client.isInitialized());
+        assertFalse("client was offline", client.isOffline());
+        assertEquals(flagValueA, client.stringVariation(flagKeyA, "defaultA"));
+
+        client.identify(contextB).get();
+        assertEquals(flagValueB, client.stringVariation(flagKeyB, "defaultB"));
+    }
 }

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/AndroidPlatformState.java

@@ -160,7 +160,12 @@ public File getCacheDir() {
     public void close() {
         connectivityChangeListeners.clear();
         foregroundChangeListeners.clear();
-        application.unregisterReceiver(connectivityReceiver);
+        try {
+            application.unregisterReceiver(connectivityReceiver);
+        } catch (IllegalArgumentException e) {
+            // getting here just means the receiver wasn't registered, which is our objective
+        }
+
         application.unregisterActivityLifecycleCallbacks(lifecycleCallbacks);
     }
 

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/ClientContextImpl.java

@@ -123,6 +123,21 @@ public static ClientContextImpl forDataSource(
         );
     }
 
+    /**
+     * Sets the evaluation context and returns a new instance of {@link ClientContextImpl}
+     * @param context to now use as the evaluation context
+     * @return a new instance
+     */
+    public ClientContextImpl setEvaluationContext(LDContext context) {
+        return new ClientContextImpl(
+            super.setEvaluationContext(context),
+            this.diagnosticStore,
+            this.fetcher,
+            this.platformState,
+            this.taskExecutor
+        );
+    }
+
     public DiagnosticStore getDiagnosticStore() {
         return diagnosticStore;
     }

launchdarkly-android-client-sdk/src/main/java/com/launchdarkly/sdk/android/ConnectivityManager.java

@@ -54,7 +54,6 @@ class ConnectivityManager {
     private final DataSourceUpdateSink dataSourceUpdateSink;
     private final ConnectionInformationState connectionInformation;
     private final PersistentDataStoreWrapper.PerEnvironmentData environmentStore;
-    private final ContextDataManager contextDataManager;
     private final EventProcessor eventProcessor;
     private final PlatformState.ForegroundChangeListener foregroundListener;
     private final PlatformState.ConnectivityChangeListener connectivityChangeListener;
@@ -66,7 +65,7 @@ class ConnectivityManager {
     private final AtomicBoolean started = new AtomicBoolean();
     private final AtomicBoolean closed = new AtomicBoolean();
     private final AtomicReference<DataSource> currentDataSource = new AtomicReference<>();
-    private final AtomicReference<LDContext> currentEvaluationContext = new AtomicReference<>();
+    private final AtomicReference<LDContext> currentContext = new AtomicReference<>();
     private final AtomicReference<Boolean> previouslyInBackground = new AtomicReference<>();
     private final LDLogger logger;
     private volatile boolean initialized = false;
@@ -76,19 +75,23 @@ class ConnectivityManager {
     // data is stored; 2. to implement additional logic that does not depend on what kind of data
     // source we're using, like "if there was an error, update the ConnectionInformation."
     private class DataSourceUpdateSinkImpl implements DataSourceUpdateSink {
+        private final ContextDataManager contextDataManager;
         private final AtomicReference<ConnectionMode> connectionMode = new AtomicReference<>(null);
         private final AtomicReference<LDFailure> lastFailure = new AtomicReference<>(null);
 
+        DataSourceUpdateSinkImpl(ContextDataManager contextDataManager) {
+            this.contextDataManager = contextDataManager;
+        }
+
         @Override
-        public void init(Map<String, DataModel.Flag> items) {
-            contextDataManager.initData(currentEvaluationContext.get(),
-                    EnvironmentData.usingExistingFlagsMap(items));
+        public void init(LDContext context, Map<String, DataModel.Flag> items) {
+            contextDataManager.initData(context, EnvironmentData.usingExistingFlagsMap(items));
             // Currently, contextDataManager is responsible for firing any necessary flag change events.
         }
 
         @Override
-        public void upsert(DataModel.Flag item) {
-            contextDataManager.upsert(item);
+        public void upsert(LDContext context, DataModel.Flag item) {
+            contextDataManager.upsert(context, item);
             // Currently, contextDataManager is responsible for firing any necessary flag change events.
         }
 
@@ -148,15 +151,14 @@ public void shutDown() {
     ) {
         this.baseClientContext = clientContext;
         this.dataSourceFactory = dataSourceFactory;
-        this.dataSourceUpdateSink = new DataSourceUpdateSinkImpl();
+        this.dataSourceUpdateSink = new DataSourceUpdateSinkImpl(contextDataManager);
         this.platformState = ClientContextImpl.get(clientContext).getPlatformState();
         this.eventProcessor = eventProcessor;
-        this.contextDataManager = contextDataManager;
         this.environmentStore = environmentStore;
         this.taskExecutor = ClientContextImpl.get(clientContext).getTaskExecutor();
         this.logger = clientContext.getBaseLogger();
 
-        currentEvaluationContext.set(clientContext.getEvaluationContext());
+        currentContext.set(clientContext.getEvaluationContext());
         forcedOffline.set(clientContext.isSetOffline());
 
         LDConfig ldConfig = clientContext.getConfig();
@@ -172,20 +174,28 @@ public void shutDown() {
         foregroundListener = foreground -> {
             DataSource dataSource = currentDataSource.get();
             if (dataSource == null || dataSource.needsRefresh(!foreground,
-                    currentEvaluationContext.get())) {
+                    currentContext.get())) {
                 updateDataSource(true, LDUtil.noOpCallback());
             }
         };
         platformState.addForegroundChangeListener(foregroundListener);
     }
 
-    void setEvaluationContext(@NonNull LDContext newContext, @NonNull Callback<Void> onCompletion) {
+    /**
+     * Switches the {@link ConnectivityManager} to begin fetching/receiving information
+     * relevant to the context provided.  This is likely to result in the teardown of existing
+     * connections, but the timing of that is not guaranteed.
+     *
+     * @param context to swtich to
+     * @param onCompletion callback that indicates when the switching is done
+     */
+    void switchToContext(@NonNull LDContext context, @NonNull Callback<Void> onCompletion) {
         DataSource dataSource = currentDataSource.get();
-        LDContext oldContext = currentEvaluationContext.getAndSet(newContext);
-        if (oldContext == newContext || oldContext.equals(newContext)) {
+        LDContext oldContext = currentContext.getAndSet(context);
+        if (oldContext == context || oldContext.equals(context)) {
             onCompletion.onSuccess(null);
         } else {
-            if (dataSource == null || dataSource.needsRefresh(!platformState.isForeground(), newContext)) {
+            if (dataSource == null || dataSource.needsRefresh(!platformState.isForeground(), context)) {
                 updateDataSource(true, onCompletion);
             } else {
                 onCompletion.onSuccess(null);
@@ -204,7 +214,7 @@ private synchronized boolean updateDataSource(
         boolean forceOffline = forcedOffline.get();
         boolean networkEnabled = platformState.isNetworkAvailable();
         boolean inBackground = !platformState.isForeground();
-        LDContext evaluationContext = currentEvaluationContext.get();
+        LDContext context = currentContext.get();
 
         eventProcessor.setOffline(forceOffline || !networkEnabled);
         eventProcessor.setInBackground(inBackground);
@@ -241,7 +251,7 @@ private synchronized boolean updateDataSource(
         ClientContext clientContext = ClientContextImpl.forDataSource(
                 baseClientContext,
                 dataSourceUpdateSink,
-                evaluationContext,
+                context,
                 inBackground,
                 previouslyInBackground.get()
         );
@@ -357,13 +367,6 @@ synchronized boolean startUp(@NonNull Callback<Void> onCompletion) {
             return false;
         }
         initialized = false;
-
-        // Calling initFromStoredData updates the current flag state *if* stored flags exist for
-        // this context. If they don't, it has no effect. Currently we do *not* return early from
-        // initialization just because stored flags exist; we're just making them available in case
-        // initialization times out or otherwise fails.
-        contextDataManager.initFromStoredData(currentEvaluationContext.get());
-
         return updateDataSource(true, onCompletion);
     }
 
@@ -400,12 +403,12 @@ synchronized ConnectionInformation getConnectionInformation() {
 
     static void fetchAndSetData(
             FeatureFetcher fetcher,
-            LDContext currentContext,
+            LDContext contextToFetch,
             DataSourceUpdateSink dataSourceUpdateSink,
             Callback<Boolean> resultCallback,
             LDLogger logger
     ) {
-        fetcher.fetch(currentContext, new Callback<String>() {
+        fetcher.fetch(contextToFetch, new Callback<String>() {
             @Override
             public void onSuccess(String flagsJson) {
                 EnvironmentData data;
@@ -417,15 +420,15 @@ public void onSuccess(String flagsJson) {
                             e, LDFailure.FailureType.INVALID_RESPONSE_BODY));
                     return;
                 }
-                dataSourceUpdateSink.init(data.getAll());
+                dataSourceUpdateSink.init(contextToFetch, data.getAll());
                 resultCallback.onSuccess(true);
             }
 
             @Override
             public void onError(Throwable e) {
                 logger.error("Error when attempting to get flag data: [{}] [{}]: {}",
-                        LDUtil.base64Url(currentContext),
-                        currentContext,
+                        LDUtil.base64Url(contextToFetch),
+                        contextToFetch,
                         LogValues.exceptionSummary(e));
                 resultCallback.onError(e);
             }