From 3fc7b8734111101962fd7ea31989e99f0a57a2d7 Mon Sep 17 00:00:00 2001
From: Casey Waldren <cwaldren@launchdarkly.com>
Date: Wed, 7 Feb 2024 14:12:33 -0800
Subject: [PATCH 1/2] fix(client-sdk): handle omitted evaluation result value
 when deserializing

---
 .../serialization/json_evaluation_result.cpp  | 28 +++++++++++--------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/libs/internal/src/serialization/json_evaluation_result.cpp b/libs/internal/src/serialization/json_evaluation_result.cpp
index 7b7b8a335..51937d991 100644
--- a/libs/internal/src/serialization/json_evaluation_result.cpp
+++ b/libs/internal/src/serialization/json_evaluation_result.cpp
@@ -56,15 +56,21 @@ tl::expected<std::optional<EvaluationResult>, JsonError> tag_invoke(
     // when deserializing FlagMeta. Primarily `variation` not
     // `variationIndex`.
 
-    auto* value_iter = json_obj.find("value");
-    if (value_iter == json_obj.end()) {
-        return tl::unexpected(JsonError::kSchemaFailure);
-    }
-
-    auto maybe_value = boost::json::value_to<tl::expected<Value, JsonError>>(
-        value_iter->value());
-    if (!maybe_value) {
-        return tl::unexpected(maybe_value.error());
+    // We're looking for the evaluated value. If it's not there, we should treat
+    // it as null and *not* a schema error. This is because the server-side SDK
+    // that produced the EvaluationResult may have omitted the 'null' value.
+    // Otherwise, if it is there, it must deserialize to a valid Value (which
+    // might itself be null.)
+    Value value = Value::Null();
+    if (auto* value_iter = json_obj.find("value");
+        value_iter != json_obj.end()) {
+        auto maybe_value =
+            boost::json::value_to<tl::expected<Value, JsonError>>(
+                value_iter->value());
+        if (!maybe_value) {
+            return tl::unexpected(maybe_value.error());
+        }
+        value = *maybe_value;
     }
 
     auto* variation_iter = json_obj.find("variation");
@@ -85,7 +91,7 @@ tl::expected<std::optional<EvaluationResult>, JsonError> tag_invoke(
                 track_events,
                 track_reason,
                 debug_events_until_date,
-                EvaluationDetailInternal(*maybe_value, variation,
+                EvaluationDetailInternal(std::move(value), variation,
                                          std::make_optional(reason.value()))};
         }
         // We could not parse the reason.
@@ -99,7 +105,7 @@ tl::expected<std::optional<EvaluationResult>, JsonError> tag_invoke(
         track_events,
         track_reason,
         debug_events_until_date,
-        EvaluationDetailInternal(*maybe_value, variation, std::nullopt)};
+        EvaluationDetailInternal(std::move(value), variation, std::nullopt)};
 }
 
 void tag_invoke(boost::json::value_from_tag const& unused,

From bb2b99f69ec1c96bc39fcce2f960058e0938612c Mon Sep 17 00:00:00 2001
From: Casey Waldren <cwaldren@launchdarkly.com>
Date: Tue, 12 Mar 2024 12:53:57 -0700
Subject: [PATCH 2/2] add a story ID

---
 libs/internal/src/serialization/json_evaluation_result.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/libs/internal/src/serialization/json_evaluation_result.cpp b/libs/internal/src/serialization/json_evaluation_result.cpp
index 51937d991..6583cc70f 100644
--- a/libs/internal/src/serialization/json_evaluation_result.cpp
+++ b/libs/internal/src/serialization/json_evaluation_result.cpp
@@ -8,7 +8,6 @@
 #include <boost/json.hpp>
 
 namespace launchdarkly {
-
 tl::expected<std::optional<EvaluationResult>, JsonError> tag_invoke(
     boost::json::value_to_tag<
         tl::expected<std::optional<EvaluationResult>, JsonError>> const& unused,
@@ -56,6 +55,7 @@ tl::expected<std::optional<EvaluationResult>, JsonError> tag_invoke(
     // when deserializing FlagMeta. Primarily `variation` not
     // `variationIndex`.
 
+    // todo(cwaldren): SC-203949 + SC-236165
     // We're looking for the evaluated value. If it's not there, we should treat
     // it as null and *not* a schema error. This is because the server-side SDK
     // that produced the EvaluationResult may have omitted the 'null' value.
@@ -133,7 +133,7 @@ void tag_invoke(boost::json::value_from_tag const& unused,
             "debugEventsUntilDate",
             std::chrono::duration_cast<std::chrono::milliseconds>(
                 evaluation_result.DebugEventsUntilDate()->time_since_epoch())
-                .count());
+            .count());
     }
 
     auto& detail = evaluation_result.Detail();
@@ -149,5 +149,4 @@ void tag_invoke(boost::json::value_from_tag const& unused,
         obj.emplace("reason", reason_json);
     }
 }
-
-}  // namespace launchdarkly
+} // namespace launchdarkly