feat: implement add column/delete column (#486)

Author: gty404

src/iceberg/json_internal.cc

@@ -277,6 +277,9 @@ nlohmann::json ToJson(const SchemaField& field) {
   json[kName] = field.name();
   json[kRequired] = !field.optional();
   json[kType] = ToJson(*field.type());
+  if (!field.doc().empty()) {
+    json[kDoc] = field.doc();
+  }
   return json;
 }
 
@@ -513,9 +516,10 @@ Result<std::unique_ptr<SchemaField>> FieldFromJson(const nlohmann::json& json) {
   ICEBERG_ASSIGN_OR_RAISE(auto field_id, GetJsonValue<int32_t>(json, kId));
   ICEBERG_ASSIGN_OR_RAISE(auto name, GetJsonValue<std::string>(json, kName));
   ICEBERG_ASSIGN_OR_RAISE(auto required, GetJsonValue<bool>(json, kRequired));
+  ICEBERG_ASSIGN_OR_RAISE(auto doc, GetJsonValueOrDefault<std::string>(json, kDoc));
 
   return std::make_unique<SchemaField>(field_id, std::move(name), std::move(type),
-                                       !required);
+                                       !required, doc);
 }
 
 Result<std::unique_ptr<Schema>> SchemaFromJson(const nlohmann::json& json) {

src/iceberg/schema_field.cc

@@ -20,28 +20,29 @@
 #include "iceberg/schema_field.h"
 
 #include <format>
+#include <string_view>
 
 #include "iceberg/type.h"
 #include "iceberg/util/formatter.h"  // IWYU pragma: keep
 
 namespace iceberg {
 
-SchemaField::SchemaField(int32_t field_id, std::string name, std::shared_ptr<Type> type,
-                         bool optional, std::string doc)
+SchemaField::SchemaField(int32_t field_id, std::string_view name,
+                         std::shared_ptr<Type> type, bool optional, std::string_view doc)
     : field_id_(field_id),
-      name_(std::move(name)),
+      name_(name),
       type_(std::move(type)),
       optional_(optional),
-      doc_(std::move(doc)) {}
+      doc_(doc) {}
 
-SchemaField SchemaField::MakeOptional(int32_t field_id, std::string name,
-                                      std::shared_ptr<Type> type, std::string doc) {
-  return {field_id, std::move(name), std::move(type), true, std::move(doc)};
+SchemaField SchemaField::MakeOptional(int32_t field_id, std::string_view name,
+                                      std::shared_ptr<Type> type, std::string_view doc) {
+  return {field_id, name, std::move(type), true, doc};
 }
 
-SchemaField SchemaField::MakeRequired(int32_t field_id, std::string name,
-                                      std::shared_ptr<Type> type, std::string doc) {
-  return {field_id, std::move(name), std::move(type), false, std::move(doc)};
+SchemaField SchemaField::MakeRequired(int32_t field_id, std::string_view name,
+                                      std::shared_ptr<Type> type, std::string_view doc) {
+  return {field_id, name, std::move(type), false, doc};
 }
 
 int32_t SchemaField::field_id() const { return field_id_; }

src/iceberg/schema_field.h

@@ -46,15 +46,15 @@ class ICEBERG_EXPORT SchemaField : public iceberg::util::Formattable {
   /// \param[in] type The field type.
   /// \param[in] optional Whether values of this field are required or nullable.
   /// \param[in] doc Optional documentation string for the field.
-  SchemaField(int32_t field_id, std::string name, std::shared_ptr<Type> type,
-              bool optional, std::string doc = {});
+  SchemaField(int32_t field_id, std::string_view name, std::shared_ptr<Type> type,
+              bool optional, std::string_view doc = {});
 
   /// \brief Construct an optional (nullable) field.
-  static SchemaField MakeOptional(int32_t field_id, std::string name,
-                                  std::shared_ptr<Type> type, std::string doc = {});
+  static SchemaField MakeOptional(int32_t field_id, std::string_view name,
+                                  std::shared_ptr<Type> type, std::string_view doc = {});
   /// \brief Construct a required (non-null) field.
-  static SchemaField MakeRequired(int32_t field_id, std::string name,
-                                  std::shared_ptr<Type> type, std::string doc = {});
+  static SchemaField MakeRequired(int32_t field_id, std::string_view name,
+                                  std::shared_ptr<Type> type, std::string_view doc = {});
 
   /// \brief Get the field ID.
   [[nodiscard]] int32_t field_id() const;

src/iceberg/test/CMakeLists.txt

@@ -170,6 +170,7 @@ if(ICEBERG_BUILD_BUNDLE)
                    transaction_test.cc
                    update_partition_spec_test.cc
                    update_properties_test.cc
+                   update_schema_test.cc
                    update_sort_order_test.cc)
 
   add_iceberg_test(data_writer_test USE_BUNDLE SOURCES data_writer_test.cc)