fix: Keep the override flags in the all flags state when the store fails

When the store cannot list its flags, the state without overrides is
invalid and empty. Overrides only add to it, so the state now holds the
override layer's flags and stays invalid, and the failure is logged as
before. A client-side SDK bootstrapped from the state uses its flags
whatever $valid says, so the overridden values still reach it.

Author: kinyoklion

lib/sdk/server/src/main/java/com/launchdarkly/sdk/server/InputValidatingEvaluator.java

@@ -208,6 +208,7 @@ public FeatureFlagsState allFlagsState(LDContext context, FlagsStateOption... op
 
     boolean clientSideOnly = FlagsStateOption.hasOption(options, FlagsStateOption.CLIENT_SIDE_ONLY);
     DataStoreTypes.KeyedItems<DataStoreTypes.ItemDescriptor> flags;
+    boolean valid = true;
     if (overrideFlags != null) {
       flags = overrideFlags;
     } else {
@@ -216,7 +217,17 @@ public FeatureFlagsState allFlagsState(LDContext context, FlagsStateOption... op
       } catch (Exception e) {
         logger.error("Exception from data store when evaluating all flags: {}", LogValues.exceptionSummary(e));
         logger.debug(e.toString(), LogValues.exceptionTrace(e));
-        return builder.valid(false).build();
+        // Overrides only add to the state. Without them the state is invalid and empty here, so it
+        // holds the override layer's flags and stays invalid. A client-side SDK bootstrapped from the
+        // state uses its flags whatever $valid says (js-client-sdk 3.x and the 4.x browser SDK only
+        // log a warning), so the overridden values still reach it.
+        Map<String, DataStoreTypes.ItemDescriptor> layerFlags =
+            overrideLayer == null ? Collections.emptyMap() : overrideLayer.all(FEATURES);
+        if (layerFlags.isEmpty()) {
+          return builder.valid(false).build();
+        }
+        flags = new DataStoreTypes.KeyedItems<>(layerFlags.entrySet());
+        valid = false;
       }
     }
 
@@ -243,7 +254,7 @@ public FeatureFlagsState allFlagsState(LDContext context, FlagsStateOption... op
             .withOverrideAffected(flag.isOverride()));
       }
     }
-    return builder.build();
+    return builder.valid(valid).build();
   }
 
   private static DataModel.FeatureFlag getFlag(ReadOnlyStore store, String key) {

lib/sdk/server/src/test/java/com/launchdarkly/sdk/server/LDClientOverridesTest.java

@@ -232,17 +232,28 @@ public void allFlagsStateBeforeInitializationExcludesLaunchDarklyDataFromAStoreW
   }
 
   @Test
-  public void allFlagsStateIsInvalidWhenTheStoreFailsEvenWithOverrides() throws Exception {
-    // A daemon-mode client whose store holds an init marker but cannot list its flags reports an
-    // invalid state and logs the failure, as it does without a source, rather than a valid state that
-    // holds only the overrides.
+  public void allFlagsStateWhenTheStoreFailsHoldsTheOverridesAndIsInvalid() throws Exception {
+    // A daemon-mode client whose store holds an init marker but cannot list its flags logs the
+    // failure. Without a source the state is invalid and empty; the overrides add to it, so it holds
+    // the overridden flags and stays invalid.
     FixedDataStore store = new FixedDataStore(flagsOnly(), true);
     store.getAllError = new RuntimeException("store failed");
     TestOverrideSource source = new TestOverrideSource(flagsOnly(valueFlag("overridden", "override-value")));
-    LDConfig config = configWith(Components.dataSystem().daemon(context -> store).overrides(source))
-        .startWait(Duration.ZERO)
-        .build();
-    try (LDClient client = new LDClient(SDK_KEY, config)) {
+    try (LDClient client = new LDClient(SDK_KEY, daemonConfig(store, source))) {
+      FeatureFlagsState state = client.allFlagsState(CONTEXT, FlagsStateOption.WITH_REASONS);
+      assertFalse(state.isValid());
+      assertEquals(Collections.singletonMap("overridden", LDValue.of("override-value")), state.toValuesMap());
+      assertTrue(state.getFlagReason("overridden").isOverrideAffected());
+      assertTrue(logCapture.getMessageStrings().stream().anyMatch(m ->
+          m.startsWith("ERROR:Exception from data store when evaluating all flags") && m.contains("store failed")));
+    }
+  }
+
+  @Test
+  public void allFlagsStateWhenTheStoreFailsAndTheLayerHoldsNoFlagsIsInvalidAndEmpty() throws Exception {
+    FixedDataStore store = new FixedDataStore(flagsOnly(), true);
+    store.getAllError = new RuntimeException("store failed");
+    try (LDClient client = new LDClient(SDK_KEY, daemonConfig(store, new TestOverrideSource(Collections.emptyList())))) {
       FeatureFlagsState state = client.allFlagsState(CONTEXT);
       assertFalse(state.isValid());
       assertEquals(Collections.emptyMap(), state.toValuesMap());
@@ -251,6 +262,12 @@ public void allFlagsStateIsInvalidWhenTheStoreFailsEvenWithOverrides() throws Ex
     }
   }
 
+  private LDConfig daemonConfig(DataStore store, TestOverrideSource source) {
+    return configWith(Components.dataSystem().daemon(context -> store).overrides(source))
+        .startWait(Duration.ZERO)
+        .build();
+  }
+
   @Test
   public void allFlagsStateTurnsOffEventTrackingForOverrideAffectedFlags() throws Exception {
     long debugUntil = System.currentTimeMillis() + 100000;