feat: Add validation for AssertCurrentSchemaID (#286)

Author: shangxinli

src/iceberg/table_requirement.cc

@@ -54,7 +54,24 @@ Status AssertLastAssignedFieldId::Validate(const TableMetadata* base) const {
 }
 
 Status AssertCurrentSchemaID::Validate(const TableMetadata* base) const {
-  return NotImplemented("AssertCurrentTableSchemaID::Validate not implemented");
+  // Validate that the current schema ID matches the one used when the metadata was read
+
+  if (base == nullptr) {
+    return CommitFailed("Requirement failed: current table metadata is missing");
+  }
+
+  if (!base->current_schema_id.has_value()) {
+    return CommitFailed(
+        "Requirement failed: current schema ID is not set in table metadata");
+  }
+
+  if (base->current_schema_id.value() != schema_id_) {
+    return CommitFailed(
+        "Requirement failed: current schema ID does not match (expected={}, actual={})",
+        schema_id_, base->current_schema_id.value());
+  }
+
+  return {};
 }
 
 Status AssertLastAssignedPartitionId::Validate(const TableMetadata* base) const {

src/iceberg/test/table_metadata_builder_test.cc

@@ -231,6 +231,39 @@ TEST_F(TableMetadataBuilderTest, TableRequirementAssertUUIDCaseInsensitive) {
   ASSERT_THAT(requirement.Validate(base_metadata_.get()), IsOk());
 }
 
+TEST_F(TableMetadataBuilderTest, TableRequirementAssertCurrentSchemaIDSuccess) {
+  base_metadata_->current_schema_id = 5;
+  table::AssertCurrentSchemaID requirement(5);
+
+  ASSERT_THAT(requirement.Validate(base_metadata_.get()), IsOk());
+}
+
+TEST_F(TableMetadataBuilderTest, TableRequirementAssertCurrentSchemaIDMismatch) {
+  base_metadata_->current_schema_id = 5;
+  table::AssertCurrentSchemaID requirement(10);
+
+  auto status = requirement.Validate(base_metadata_.get());
+  EXPECT_THAT(status, IsError(ErrorKind::kCommitFailed));
+  EXPECT_THAT(status, HasErrorMessage("schema ID does not match"));
+}
+
+TEST_F(TableMetadataBuilderTest, TableRequirementAssertCurrentSchemaIDNullBase) {
+  table::AssertCurrentSchemaID requirement(5);
+
+  auto status = requirement.Validate(nullptr);
+  EXPECT_THAT(status, IsError(ErrorKind::kCommitFailed));
+  EXPECT_THAT(status, HasErrorMessage("metadata is missing"));
+}
+
+TEST_F(TableMetadataBuilderTest, TableRequirementAssertCurrentSchemaIDNotSet) {
+  base_metadata_->current_schema_id = std::nullopt;
+  table::AssertCurrentSchemaID requirement(5);
+
+  auto status = requirement.Validate(base_metadata_.get());
+  EXPECT_THAT(status, IsError(ErrorKind::kCommitFailed));
+  EXPECT_THAT(status, HasErrorMessage("schema ID is not set"));
+}
+
 // ============================================================================
 // Integration Tests - End-to-End Workflow
 // ============================================================================