Copilot commented on code in PR #801:
URL: https://github.com/apache/iceberg-cpp/pull/801#discussion_r4001772372


##########
src/iceberg/inspect/snapshots_table.cc:
##########
@@ -19,21 +19,142 @@
 
 #include "iceberg/inspect/snapshots_table.h"
 
+#include <chrono>
+#include <cstddef>
 #include <memory>
+#include <optional>
 #include <utility>
 #include <vector>
 
+#include <nanoarrow/nanoarrow.h>
+
+#include "iceberg/arrow_c_data_util_internal.h"
+#include "iceberg/arrow_row_builder_internal.h"
+#include "iceberg/nanoarrow_status_internal.h"
 #include "iceberg/schema.h"
 #include "iceberg/schema_field.h"
+#include "iceberg/schema_internal.h"
+#include "iceberg/snapshot.h"
 #include "iceberg/table.h"
-#include "iceberg/table_identifier.h"
+#include "iceberg/table_metadata.h"
 #include "iceberg/type.h"
+#include "iceberg/util/macros.h"
 
 namespace iceberg {
 namespace {
 
-std::shared_ptr<Schema> MakeSnapshotsTableSchema() {
-  return std::make_shared<Schema>(std::vector<SchemaField>{
+Status AppendSnapshot(ArrowRowBuilder& builder, const Snapshot& snapshot) {
+  ICEBERG_RETURN_UNEXPECTED(
+      AppendInt(builder.column(0), 
std::chrono::duration_cast<std::chrono::microseconds>(
+                                       
snapshot.timestamp_ms.time_since_epoch())
+                                       .count()));
+  ICEBERG_RETURN_UNEXPECTED(AppendInt(builder.column(1), 
snapshot.snapshot_id));
+
+  if (snapshot.parent_snapshot_id.has_value()) {
+    ICEBERG_RETURN_UNEXPECTED(AppendInt(builder.column(2), 
*snapshot.parent_snapshot_id));
+  } else {
+    ICEBERG_RETURN_UNEXPECTED(AppendNull(builder.column(2)));
+  }
+
+  auto operation = snapshot.Operation();
+  if (operation.has_value()) {
+    ICEBERG_RETURN_UNEXPECTED(AppendString(builder.column(3), *operation));
+  } else {
+    ICEBERG_RETURN_UNEXPECTED(AppendNull(builder.column(3)));
+  }
+
+  ICEBERG_RETURN_UNEXPECTED(AppendString(builder.column(4), 
snapshot.manifest_list));
+
+  if (!snapshot.summary.empty()) {
+    if (snapshot.summary.contains(SnapshotSummaryFields::kOperation)) {
+      auto summary = snapshot.summary;
+      summary.erase(SnapshotSummaryFields::kOperation);
+      ICEBERG_RETURN_UNEXPECTED(AppendStringMap(builder.column(5), summary));
+    } else {
+      ICEBERG_RETURN_UNEXPECTED(AppendStringMap(builder.column(5), 
snapshot.summary));
+    }
+  } else {
+    ICEBERG_RETURN_UNEXPECTED(AppendNull(builder.column(5)));
+  }

Review Comment:
   PR description says the snapshots table should "emit null when the remaining 
summary is empty" after removing the operation key, but the current 
implementation always emits an (empty) map when `summary` only contains 
`operation` because `AppendStringMap` finishes a non-null empty map element. 
This makes the wire semantics disagree with the stated contract (and downstream 
consumers can’t distinguish “missing summary” vs “present but empty”). Consider 
appending null when `summary.erase(kOperation)` leaves the map empty.



##########
src/iceberg/test/snapshots_table_test.cc:
##########
@@ -0,0 +1,230 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include "iceberg/inspect/snapshots_table.h"
+
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include <arrow/array.h>
+#include <arrow/c/bridge.h>
+#include <arrow/record_batch.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "iceberg/constants.h"
+#include "iceberg/inspect/metadata_table.h"
+#include "iceberg/test/matchers.h"
+#include "iceberg/test/metadata_table_test_base.h"
+
+namespace iceberg {
+namespace {
+
+std::vector<std::pair<std::string, std::string>> GetMapEntries(
+    const std::shared_ptr<::arrow::MapArray>& map_array, int64_t row) {
+  auto keys = 
std::static_pointer_cast<::arrow::StringArray>(map_array->keys());
+  auto values = 
std::static_pointer_cast<::arrow::StringArray>(map_array->items());
+  std::vector<std::pair<std::string, std::string>> entries;
+  entries.reserve(map_array->value_length(row));
+  const auto offset = map_array->value_offset(row);
+  for (int64_t index = offset; index < offset + map_array->value_length(row); 
++index) {
+    entries.emplace_back(keys->GetString(index), values->GetString(index));
+  }
+  return entries;
+}
+
+}  // namespace
+
+class SnapshotsTableTest : public MetadataTableTestBase {
+ protected:
+  void SetUp() override {
+    MetadataTableTestBase::SetUp();
+
+    auto [snap1, snap2] = MakeTestSnapshots();
+    ICEBERG_UNWRAP_OR_FAIL(
+        table_, MakeTableWithSnapshots({snap1, snap2}, 
/*current_snapshot_id=*/2));
+
+    ICEBERG_UNWRAP_OR_FAIL(snapshots_table_, 
MetadataTable::Make<SnapshotsTable>(table_));
+  }
+
+  std::unique_ptr<MetadataTable> snapshots_table_;
+};
+
+TEST_F(SnapshotsTableTest, Construct) {
+  EXPECT_EQ(snapshots_table_->kind(), MetadataTable::Kind::kSnapshots);
+  EXPECT_EQ(snapshots_table_->source_table(), table_);
+  EXPECT_NE(snapshots_table_->schema(), nullptr);
+}
+
+TEST_F(SnapshotsTableTest, Scan) {
+  // Scan the snapshots table once and verify all columns of the result.
+  ICEBERG_UNWRAP_OR_FAIL(auto stream, snapshots_table_->Scan());
+  ICEBERG_UNWRAP_OR_FAIL(auto batches, ReadAllBatches(std::move(stream)));
+  ASSERT_EQ(batches.size(), 1);
+  const auto& batch = batches.front();
+
+  // Row and column counts.
+  EXPECT_EQ(batch->num_rows(), 2);
+  EXPECT_EQ(batch->num_columns(), 6);
+
+  // Column 0: committed_at (timestamptz) — microseconds since epoch.
+  auto committed_at = 
std::static_pointer_cast<::arrow::TimestampArray>(batch->column(0));
+  EXPECT_EQ(committed_at->Value(0), 1234567890000LL * 1000);
+  EXPECT_EQ(committed_at->Value(1), 9876543210000LL * 1000);
+
+  // Column 1: snapshot_id (long) — returned in storage order.
+  auto snapshot_ids = 
std::static_pointer_cast<::arrow::Int64Array>(batch->column(1));
+  EXPECT_EQ(snapshot_ids->Value(0), 1);
+  EXPECT_EQ(snapshot_ids->Value(1), 2);
+
+  // Column 2: parent_id (long) — first snapshot has no parent.
+  auto parent_ids = 
std::static_pointer_cast<::arrow::Int64Array>(batch->column(2));
+  EXPECT_TRUE(parent_ids->IsNull(0));
+  EXPECT_FALSE(parent_ids->IsNull(1));
+  EXPECT_EQ(parent_ids->Value(1), 1);
+
+  // Column 3: operation (string).
+  auto operations = 
std::static_pointer_cast<::arrow::StringArray>(batch->column(3));
+  EXPECT_EQ(operations->GetString(0), "append");
+  EXPECT_EQ(operations->GetString(1), "append");
+
+  // Column 4: manifest_list (string).
+  auto manifest_lists = 
std::static_pointer_cast<::arrow::StringArray>(batch->column(4));
+  EXPECT_EQ(manifest_lists->GetString(0), "file:/tmp/manifest1.avro");
+  EXPECT_EQ(manifest_lists->GetString(1), "file:/tmp/manifest2.avro");
+
+  // Column 5: summary (map<string,string>) excludes the separate operation 
field.
+  auto summaries = 
std::static_pointer_cast<::arrow::MapArray>(batch->column(5));
+  EXPECT_FALSE(summaries->IsNull(0));
+  EXPECT_FALSE(summaries->IsNull(1));
+  EXPECT_EQ(summaries->value_length(0), 10);
+  EXPECT_EQ(summaries->value_length(1), 10);
+
+  auto first_summary = GetMapEntries(summaries, 0);
+  EXPECT_THAT(
+      first_summary,
+      ::testing::Not(::testing::Contains(::testing::Pair("operation", 
"append"))));
+  EXPECT_THAT(first_summary, 
::testing::Contains(::testing::Pair("total-records", "1")));
+
+  auto second_summary = GetMapEntries(summaries, 1);
+  EXPECT_THAT(
+      second_summary,
+      ::testing::Not(::testing::Contains(::testing::Pair("operation", 
"append"))));
+  EXPECT_THAT(second_summary, 
::testing::Contains(::testing::Pair("total-records", "2")));
+}
+
+TEST_F(SnapshotsTableTest, ScanEmptySnapshotList) {
+  // A table with zero snapshots should return zero rows.
+  ICEBERG_UNWRAP_OR_FAIL(
+      auto empty_table,
+      MakeTableWithSnapshots({}, /*current_snapshot_id=*/kInvalidSnapshotId));
+
+  ICEBERG_UNWRAP_OR_FAIL(snapshots_table_,
+                         MetadataTable::Make<SnapshotsTable>(empty_table));
+
+  ICEBERG_UNWRAP_OR_FAIL(auto stream, snapshots_table_->Scan());
+  ICEBERG_UNWRAP_OR_FAIL(auto batches, ReadAllBatches(std::move(stream)));
+  EXPECT_TRUE(batches.empty());
+}
+
+TEST_F(SnapshotsTableTest, ScanSkipsNullSnapshots) {
+  auto [snap1, snap2] = MakeTestSnapshots();
+  ICEBERG_UNWRAP_OR_FAIL(auto table, MakeTableWithSnapshots({snap1, nullptr, 
snap2},
+                                                            
/*current_snapshot_id=*/2));
+  ICEBERG_UNWRAP_OR_FAIL(auto snapshots_table,
+                         MetadataTable::Make<SnapshotsTable>(table));
+
+  ICEBERG_UNWRAP_OR_FAIL(auto stream, snapshots_table->Scan());
+  ICEBERG_UNWRAP_OR_FAIL(auto batches, ReadAllBatches(std::move(stream)));
+  ASSERT_EQ(batches.size(), 1);
+  EXPECT_EQ(batches.front()->num_rows(), 2);
+}
+
+TEST_F(SnapshotsTableTest, ScanEmptySummary) {
+  auto [missing_summary, operation_only_summary] = MakeTestSnapshots();
+  missing_summary->summary.clear();
+  operation_only_summary->summary = {
+      {SnapshotSummaryFields::kOperation, DataOperation::kAppend}};
+  ICEBERG_UNWRAP_OR_FAIL(auto table,
+                         MakeTableWithSnapshots({missing_summary, 
operation_only_summary},
+                                                /*current_snapshot_id=*/2));
+  ICEBERG_UNWRAP_OR_FAIL(auto snapshots_table,
+                         MetadataTable::Make<SnapshotsTable>(table));
+
+  ICEBERG_UNWRAP_OR_FAIL(auto stream, snapshots_table->Scan());
+  ICEBERG_UNWRAP_OR_FAIL(auto batches, ReadAllBatches(std::move(stream)));
+  ASSERT_EQ(batches.size(), 1);
+  auto summaries =
+      std::static_pointer_cast<::arrow::MapArray>(batches.front()->column(5));
+  EXPECT_TRUE(summaries->IsNull(0));
+  EXPECT_FALSE(summaries->IsNull(1));
+  EXPECT_EQ(summaries->value_length(1), 0);

Review Comment:
   If the snapshots table switches to emitting null for summaries that become 
empty after filtering out `operation` (per the PR description), this test 
should also expect the operation-only summary row to be null rather than a 
non-null map with zero entries.



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]


---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to