bool IsAllowedTypeChange()

in backend/schema/validators/column_validator.cc [65:107]

• 30 lines of code
• 20 McCabe index (conditional complexity)

bool IsAllowedTypeChange(const zetasql::Type* old_column_type,
                         const zetasql::Type* new_column_type) {
  if (old_column_type->Equals(new_column_type)) {
    return true;
  }

  if (old_column_type->IsArray() != new_column_type->IsArray()) {
    return false;
  }

  if (old_column_type->IsArray()) {
    return IsAllowedTypeChange(BaseType(old_column_type),
                               BaseType(new_column_type));
  }

  // Allow conversions from BYTES to STRING and STRING to BYTES.
  if ((new_column_type->IsString() && old_column_type->IsBytes()) ||
      (new_column_type->IsBytes() && old_column_type->IsString())) {
    return true;
  }

  // Allow conversions from PROTO to BYTES and BYTES to PROTO
  if ((new_column_type->IsProto() && old_column_type->IsBytes()) ||
      (new_column_type->IsBytes() && old_column_type->IsProto())) {
    return true;
  }

  // Allow conversion from PROTO to PROTO or enum to enum
  if ((new_column_type->IsProto() && old_column_type->IsProto()) ||
      (new_column_type->IsEnum() && old_column_type->IsEnum())) {
    return true;
  }

  // Allow conversion from enum to INT64 and INT64 to enum (this should ideally
  // be INT32 but since cloud spanner doesn't support INT32 columns we support
  // INT64 here)
  if ((new_column_type->IsInt64() && old_column_type->IsEnum()) ||
      (new_column_type->IsEnum() && old_column_type->IsInt64())) {
    return true;
  }

  return false;
}