address review: meson, Hive-compat note, reject no-data-files in Validate

- Add replace_partitions.h to src/iceberg/update/meson.build (manuzhang)
- Add Java-style note recommending OverwriteFiles for non-Hive use (zhjwpku)
- Validate(): call DataSpec() to reject no-data-files replace, matching
  Java BaseReplacePartitions which throws when no file was added (manuzhang)

Author: shangxinli

src/iceberg/update/meson.build

@@ -23,6 +23,7 @@ install_headers(
         'merge_append.h',
         'merging_snapshot_update.h',
         'pending_update.h',
+        'replace_partitions.h',
         'row_delta.h',
         'set_snapshot.h',
         'snapshot_manager.h',

src/iceberg/update/replace_partitions.cc

@@ -91,6 +91,11 @@ std::string ReplacePartitions::operation() { return DataOperation::kOverwrite; }
 
 Status ReplacePartitions::Validate(const TableMetadata& current_metadata,
                                    const std::shared_ptr<Snapshot>& snapshot) {
+  // Java's BaseReplacePartitions requires at least one staged data file:
+  // dataSpec() throws if none was added. Call DataSpec() up front to surface
+  // the same error here, instead of silently committing an empty snapshot.
+  ICEBERG_ASSIGN_OR_RAISE(auto data_spec, DataSpec());
+
   if (snapshot == nullptr) {
     return {};
   }

src/iceberg/update/replace_partitions.h

@@ -49,6 +49,10 @@ namespace iceberg {
 /// When committing, these changes are applied to the latest table snapshot.
 /// Commit conflicts are resolved by re-applying to the new latest snapshot
 /// and reattempting the commit.
+///
+/// \note This is provided to implement SQL compatible with Hive table
+/// operations but is not recommended. Instead, use OverwriteFiles to
+/// explicitly overwrite data.
 class ICEBERG_EXPORT ReplacePartitions : public MergingSnapshotUpdate {
  public:
   /// \brief Create a new ReplacePartitions instance.