address review: percent-decode s3a/s3n fallback to match native s3 parsing

Author: plusplusjiajia

src/iceberg/arrow/arrow_io.cc

@@ -30,6 +30,7 @@
 #include <arrow/io/interfaces.h>
 #include <arrow/result.h>
 #include <arrow/status.h>
+#include <arrow/util/uri.h>
 
 #include "iceberg/arrow/arrow_io_internal.h"
 #include "iceberg/arrow/arrow_io_util.h"
@@ -490,9 +491,10 @@ Result<std::string> ArrowFileSystemFileIO::ResolvePath(const std::string& file_l
     return std::unexpected<Error>{
         {.kind = ToErrorKind(status), .message = status.ToString()}};
   }
-  // Scheme-less bucket/key, dropping any ?query / #fragment.
+  // Scheme-less bucket/key: drop ?query / #fragment and percent-decode to match s3://.
   std::string bucket_key = file_location.substr(pos + 3);
-  return bucket_key.substr(0, bucket_key.find_first_of("?#"));
+  bucket_key = bucket_key.substr(0, bucket_key.find_first_of("?#"));
+  return ::arrow::util::UriUnescape(bucket_key);
 }
 
 Result<std::shared_ptr<::arrow::io::RandomAccessFile>> OpenArrowInputStream(

src/iceberg/test/arrow_io_test.cc

@@ -429,11 +429,12 @@ TEST_F(LocalFileIOTest, PropagatesNonSchemeMismatchUriError) {
   EXPECT_THAT(read_res, HasErrorMessage("Cannot parse URI"));
 }
 
-TEST_F(LocalFileIOTest, FallbackPreservesPercentEncodingInKey) {
-  std::string encoded_path = temp_filepath_ + "%20x";
-  ASSERT_THAT(file_io_->WriteFile(encoded_path, "raw"), IsOk());
+TEST_F(LocalFileIOTest, FallbackDecodesPercentEncodingInKey) {
+  std::string decoded_path = temp_filepath_ + " x";
+  ASSERT_THAT(file_io_->WriteFile(decoded_path, "raw"), IsOk());
 
-  auto read_res = file_io_->ReadFile(ForeignSchemeUri(encoded_path), std::nullopt);
+  auto read_res =
+      file_io_->ReadFile(ForeignSchemeUri(temp_filepath_ + "%20x"), std::nullopt);
   EXPECT_THAT(read_res, IsOk());
   EXPECT_THAT(read_res, HasValue(::testing::Eq("raw")));
 }