Steps to Reproduce

I'm getting visual glitches using this widget structure:

new Container(
      decoration: new BoxDecoration(
        color: color,
        shape: BoxShape.circle,
        border: new Border.all(
          color: Colors.white,
          width: 2.5,
        ),
      ),
      child: new Center(
        child: new Text(
          "$index",
          style: theme.textTheme.body1.apply(color: textColor),
        ),
      ),
    );

As you can notice, the background color of the decoration is slightly overflowing the circular border. I've tried in different ways (e.g. using ClipOval) but the result is always the same.

I think this behaviour, even if intended, is not what a developer/designer would expect.

Is there a way to properly achieve the expected result?

Thanks