refactor: use BigSegmentsStatus::kNone sentinel in EvaluationStack

Author: beekld

libs/server-sdk/src/evaluation/evaluation_stack.cpp

@@ -9,14 +9,16 @@ namespace {
 // independent of the enum's underlying values.
 int Precedence(enum EvaluationReason::BigSegmentsStatus status) {
     switch (status) {
-        case EvaluationReason::BigSegmentsStatus::kHealthy:
+        case EvaluationReason::BigSegmentsStatus::kNone:
             return 0;
-        case EvaluationReason::BigSegmentsStatus::kStale:
+        case EvaluationReason::BigSegmentsStatus::kHealthy:
             return 1;
-        case EvaluationReason::BigSegmentsStatus::kStoreError:
+        case EvaluationReason::BigSegmentsStatus::kStale:
             return 2;
-        case EvaluationReason::BigSegmentsStatus::kNotConfigured:
+        case EvaluationReason::BigSegmentsStatus::kStoreError:
             return 3;
+        case EvaluationReason::BigSegmentsStatus::kNotConfigured:
+            return 4;
     }
     return 0;
 }
@@ -56,14 +58,14 @@ data_components::BigSegmentStoreWrapper* EvaluationStack::BigSegmentStore()
     return big_segment_store_;
 }
 
-void EvaluationStack::RecordBigSegmentsStatus(enum EvaluationReason::BigSegmentsStatus status) {
-    if (!big_segments_status_ ||
-        Precedence(status) > Precedence(*big_segments_status_)) {
+void EvaluationStack::RecordBigSegmentsStatus(
+    enum EvaluationReason::BigSegmentsStatus status) {
+    if (Precedence(status) > Precedence(big_segments_status_)) {
         big_segments_status_ = status;
     }
 }
 
-std::optional<enum EvaluationReason::BigSegmentsStatus>
+enum EvaluationReason::BigSegmentsStatus
 EvaluationStack::BigSegmentsStatus() const {
     return big_segments_status_;
 }

libs/server-sdk/src/evaluation/evaluation_stack.hpp

@@ -84,10 +84,11 @@ class EvaluationStack {
     void RecordBigSegmentsStatus(enum EvaluationReason::BigSegmentsStatus status);
 
     /**
-     * @return The aggregated Big Segments status, or std::nullopt if no Big
-     * Segment was queried during this evaluation.
+     * @return The aggregated Big Segments status, or kNone if no Big Segment
+     * was queried during this evaluation.
      */
-    [[nodiscard]] std::optional<enum EvaluationReason::BigSegmentsStatus> BigSegmentsStatus() const;
+    [[nodiscard]] enum EvaluationReason::BigSegmentsStatus BigSegmentsStatus()
+        const;
 
     /**
      * Returns the cached membership for a context key looked up earlier in this
@@ -121,7 +122,8 @@ class EvaluationStack {
     std::unordered_set<std::string> segments_seen_;
 
     data_components::BigSegmentStoreWrapper* big_segment_store_;
-    std::optional<enum EvaluationReason::BigSegmentsStatus> big_segments_status_;
+    enum EvaluationReason::BigSegmentsStatus big_segments_status_ =
+        EvaluationReason::BigSegmentsStatus::kNone;
     // Keyed by unhashed context key. Empty until the first Big Segment lookup.
     std::unordered_map<std::string, integrations::Membership> memberships_;
     std::unordered_set<std::string> store_error_keys_;

libs/server-sdk/src/evaluation/evaluator.cpp

@@ -53,8 +53,9 @@ EvaluationDetail<Value> Evaluator::Evaluate(
     EventScope const& event_scope) {
     EvaluationStack stack{big_segment_store_};
     auto detail = Evaluate(std::nullopt, flag, context, stack, event_scope);
-    if (auto status = stack.BigSegmentsStatus()) {
-        return WithBigSegmentsStatus(std::move(detail), *status);
+    auto status = stack.BigSegmentsStatus();
+    if (status != EvaluationReason::BigSegmentsStatus::kNone) {
+        return WithBigSegmentsStatus(std::move(detail), status);
     }
     return detail;
 }

libs/server-sdk/tests/big_segment_evaluator_test.cpp

@@ -207,7 +207,8 @@ TEST_F(BigSegmentEvaluatorTest, ContextLacksUnboundedKindDoesNotQuery) {
         eval.Evaluate(store_.GetFlag("flag")->item.value(), AliceUser());
 
     EXPECT_EQ(*detail, Value(true));
-    EXPECT_EQ(detail.Reason()->BigSegmentsStatus(), std::nullopt);
+    EXPECT_EQ(detail.Reason()->BigSegmentsStatus(),
+              EvaluationReason::BigSegmentsStatus::kNone);
     EXPECT_EQ(fake_->MembershipCalls(), 0);
 }