[Bug] Circle line lost when boundary gap false in the stack bar on polar chart

[jieun94]

Version

5.5.1

Link to Minimal Reproduction

https://codepen.io/jieun94/pen/xxoZXrX

Steps to Reproduce

1. Enter the wind direction value of length 16 in the category to indicate 16 orientation
2. False the boundary gap to position the north in the 0 degree direction

Current Behavior

The line between the last category and the first category is lost.

Expected Behavior

The line between the last category and the first category is connected to form a circle.

Environment

- OS: window 11 
- Browser: Chrome/124.0.0.0
- Framework : vue3

Any additional comments?

No response

[Ovilia]

After digging into the code, I found this is not-a-bug. In fact, this is the result of intentionally adjusted so that bars don't get mixed. For example, if we have the following data with boundaryGap: false without adjusting

{
    type: 'bar',
    data: [10, 20, 30, 40],
    coordinateSystem: 'polar',
    itemStyle: {
        opacity: 0.5
    }
}

The first data is overlapped with the last data.

To avoid this, this commit introduced a way to adjust the range according to data count.

And here is why we cannot just change the axisLine and axisSplitLine to become a circle: it's logically not consistant when it's slightly not match a circle. So the result of https://codepen.io/jieun94/pen/xxoZXrX should be regarded as by design, although it may seem to be unexpected at the first sight.