Bug summary

The logic for setting linestyle using a dash tuple, i.e.(offset, onoffseq), does not properly handle the case whereonoffseq isNone.

Code for reproduction

print(mpl.lines.Line2D([], [],linestyle=(0,None)).get_linestyle())

Actual outcome

'--'

Expected outcome

Ideally, dash values would roundtrip, so the return would be(0, None). Even when the dash sequence is notNone, a lot of information is lost when this property is queried.

But more narrowly,(0, None) draws a solid line, so the return value should be'-'.

Additional information

The main consequence here is that the line's capstyle appears to conditionally read fromsolid_capstyle ordash_capstyle depending on theget_linestyle return value.

Matplotlib Version

3.5.2