refactor: let CastNonPartitionArrayIfNeed only handle casting, leave name mapping to MappingFields in FieldMapping (alibaba#293)

Author: lxy-9602

src/paimon/common/data/blob_defs.h

@@ -33,7 +33,7 @@ class BlobDefs {
     /// To create a Blob field:
     /// @code
     ///   std::unordered_map<std::string, std::string> blob_metadata_map = {
-    ///       {Blob::EXTENSION_TYPE_KEY, Blob::EXTENSION_TYPE_VALUE}
+    ///       {Blob::kExtensionTypeKey, Blob::kExtensionTypeValue}
     ///   };
     ///   auto field = arrow::field("my_blob_field", arrow::large_binary(), false,
     ///       std::make_shared<arrow::KeyValueMetadata>(blob_metadata_map));

src/paimon/core/io/field_mapping_reader.cpp

@@ -107,7 +107,7 @@ Result<std::shared_ptr<arrow::Array>> FieldMappingReader::CastNonPartitionArrayI
                     single_column_array, non_partition_info_.non_partition_read_schema[i].Type(),
                     arrow_pool_.get()));
             casted_array.push_back(casted);
-            casted_field_names.push_back(non_partition_info_.non_partition_read_schema[i].Name());
+            casted_field_names.push_back(non_partition_info_.non_partition_data_schema[i].Name());
         } else {
             // read and data type may both be string type, but after adapter transform, type may be
             // dictionary, need reconstruct struct type

src/paimon/core/io/field_mapping_reader_test.cpp

@@ -706,4 +706,46 @@ TEST_F(FieldMappingReaderTest, TestSchemaEvolutionWithDictType) {
                 partition, expected_array);
 }
 
+TEST_F(FieldMappingReaderTest, TestReadWithSchemaEvolutionRenameCombinedCast) {
+    // Test all 4 combinations of rename × cast:
+    //   f0: no rename, no cast   (utf8 → utf8, name unchanged)
+    //   f1: rename only           (int32 → int32, f1 → new_f1)
+    //   f2: cast only             (int32 → utf8, name unchanged)
+    //   f3: rename + cast         (int32 → utf8, f3 → new_f2)
+    std::vector<DataField> data_fields = {
+        DataField(0, arrow::field("f0", arrow::utf8())),
+        DataField(1, arrow::field("f1", arrow::int32())),
+        DataField(2, arrow::field("f2", arrow::int32())),
+        DataField(3, arrow::field("f3", arrow::int32())),
+    };
+    auto data_schema = DataField::ConvertDataFieldsToArrowSchema(data_fields);
+    auto data_array = std::dynamic_pointer_cast<arrow::StructArray>(
+        arrow::ipc::internal::json::ArrayFromJSON(arrow::struct_(data_schema->fields()),
+                                                  R"([
+        ["Bob", 100, 10, 1],
+        ["Emily", 200, 20, 2],
+        ["Alice", 300, 30, 3]
+    ])")
+            .ValueOrDie());
+
+    std::vector<DataField> read_fields = {
+        DataField(0, arrow::field("f0", arrow::utf8())),
+        DataField(1, arrow::field("new_f1", arrow::int32())),
+        DataField(2, arrow::field("f2", arrow::utf8())),
+        DataField(3, arrow::field("new_f3", arrow::utf8())),
+    };
+    auto read_schema = DataField::ConvertDataFieldsToArrowSchema(read_fields);
+
+    auto expected = std::dynamic_pointer_cast<arrow::StructArray>(
+        arrow::ipc::internal::json::ArrayFromJSON(arrow::struct_(read_schema->fields()),
+                                                  R"([
+        ["Bob", 100, "10", "1"],
+        ["Emily", 200, "20", "2"],
+        ["Alice", 300, "30", "3"]
+    ])")
+            .ValueOrDie());
+
+    CheckResult(data_schema, data_array, read_schema, /*predicate=*/nullptr,
+                /*partition_keys=*/{}, BinaryRow::EmptyRow(), expected);
+}
 }  // namespace paimon::test