Bug in my brain or in pyplot? Whiskers in boxplot with iqr zero

Question

Using

x = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,10,-10]
matplotlib.pyplot.boxplot(x) 

plots the following:

Where the whiskers are invisible at -10 and 10. The definition according to the documentation however states that the whiskers are at Q1-1.5 * IQR and at Q1+1.5 * IQR. Shouldn't they be at 0 then, too?

Is this a bug, or did I misunderstand something about box plots?

Answer 1

See matplotlib issue 5331

Was considered a feature. Is solved in currently still unstable 2.0.