(iceberg-cpp) branch main updated: fix: Handle null values in GetJsonValue and its friends (#258)

[gangwu]

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gangwu pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/iceberg-cpp.git


The following commit(s) were added to refs/heads/main by this push:
     new 730cd5c  fix: Handle null values in GetJsonValue and its friends (#258)
730cd5c is described below

commit 730cd5c184bb0c7103142781672019d6358a8a17
Author: Li Feiyang <lifeiy...@zju.edu.cn>
AuthorDate: Fri Oct 17 22:02:43 2025 +0800

    fix: Handle null values in GetJsonValue and its friends (#258)
    
    The current JSON parsing logic in GetJsonValueOrDefault does not
    correctly handle cases where an optional field is present with an
    explicit null value. Now, if a key is present but its value is null, the
    function correctly returns the default value, treating it the same as a
    missing key.
---
 src/iceberg/util/json_util_internal.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/iceberg/util/json_util_internal.h 
b/src/iceberg/util/json_util_internal.h
index c525ac9..81d17b0 100644
--- a/src/iceberg/util/json_util_internal.h
+++ b/src/iceberg/util/json_util_internal.h
@@ -57,7 +57,7 @@ Result<T> GetJsonValueImpl(const nlohmann::json& json, 
std::string_view key) {
 template <typename T>
 Result<std::optional<T>> GetJsonValueOptional(const nlohmann::json& json,
                                               std::string_view key) {
-  if (!json.contains(key)) {
+  if (!json.contains(key) || json.at(key).is_null()) {
     return std::nullopt;
   }
   ICEBERG_ASSIGN_OR_RAISE(auto value, GetJsonValueImpl<T>(json, key));
@@ -66,7 +66,7 @@ Result<std::optional<T>> GetJsonValueOptional(const 
nlohmann::json& json,
 
 template <typename T>
 Result<T> GetJsonValue(const nlohmann::json& json, std::string_view key) {
-  if (!json.contains(key)) {
+  if (!json.contains(key) || json.at(key).is_null()) {
     return JsonParseError("Missing '{}' in {}", key, SafeDumpJson(json));
   }
   return GetJsonValueImpl<T>(json, key);
@@ -75,7 +75,7 @@ Result<T> GetJsonValue(const nlohmann::json& json, 
std::string_view key) {
 template <typename T>
 Result<T> GetJsonValueOrDefault(const nlohmann::json& json, std::string_view 
key,
                                 T default_value = T{}) {
-  if (!json.contains(key)) {
+  if (!json.contains(key) || json.at(key).is_null()) {
     return default_value;
   }
   return GetJsonValueImpl<T>(json, key);