protected override void Generate()

in EFCore/src/Migrations/MySQLMigrationsSqlGenerator.cs [98:177]
69 lines of code
10 McCabe index (conditional complexity)

    protected override void Generate(RenameColumnOperation operation, IModel? model, MigrationCommandListBuilder builder)
    {
      Check.NotNull(operation, nameof(operation));
      Check.NotNull(builder, nameof(builder));

      builder.Append("ALTER TABLE ")
        .Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(operation.Table, operation.Schema));

      builder.Append(" CHANGE ")
        .Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(operation.Name))
        .Append(" ");

      var column = model?.GetRelationalModel().FindTable(operation.Table, operation.Schema)?.FindColumn(operation.NewName);
      if (column == null)
      {
        if (!(operation[RelationalAnnotationNames.ColumnType] is string type))
        {
          throw new InvalidOperationException(
            $"Could not find the column: {Dependencies.SqlGenerationHelper.DelimitIdentifier(operation.Table, operation.Schema)}.{Dependencies.SqlGenerationHelper.DelimitIdentifier(operation.NewName)}. Specify the column type explicitly on 'RenameColumn' using the \"{RelationalAnnotationNames.ColumnType}\" annotation");
        }

        builder
          .Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(operation.NewName))
          .Append(" ")
          .Append(type)
          .AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);

        EndStatement(builder);
        return;
      }

      var typeMapping = column.PropertyMappings.FirstOrDefault()?.TypeMapping;
      var converter = typeMapping?.Converter;
      var clrType = (converter!.ProviderClrType ?? typeMapping!.ClrType).UnwrapNullableType();
      var columnType = (string)(operation[RelationalAnnotationNames.ColumnType]
                  ?? column[RelationalAnnotationNames.ColumnType])!;
      var isNullable = column.IsNullable;

      var defaultValue = column.DefaultValue;
      defaultValue = converter != null
        ? converter.ConvertToProvider(defaultValue)
        : defaultValue;
      defaultValue = (defaultValue == DBNull.Value ? null : defaultValue)
             ?? (isNullable
               ? null
               : clrType == typeof(string)
                 ? string.Empty
                 : clrType.IsArray
                   ? Array.CreateInstance(clrType.GetElementType()!, 0)
                   : clrType.GetDefaultValue());

      var isRowVersion = (clrType == typeof(DateTime) || clrType == typeof(byte[])) &&
               column.IsRowVersion;

      var addColumnOperation = new AddColumnOperation
      {
        Schema = operation.Schema,
        Table = operation.Table,
        Name = operation.NewName,
        ClrType = clrType,
        ColumnType = columnType,
        IsUnicode = column.IsUnicode,
        MaxLength = column.MaxLength,
        IsFixedLength = column.IsFixedLength,
        IsRowVersion = isRowVersion,
        IsNullable = isNullable,
        DefaultValue = defaultValue,
        DefaultValueSql = column.DefaultValueSql,
        ComputedColumnSql = column.ComputedColumnSql,
        IsStored = column.IsStored,
      };

      ColumnDefinition(
        addColumnOperation,
        model,
        builder);
      builder.AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);
      EndStatement(builder);

    }