Bug report

Bug summary

The Path.intersects_path function sometimes returns True when it should return False. I've noticed this only when some vertices in the path deviate slightly from round numbers (as sometimes arises from floating point imprecision).

Code for reproduction

from matplotlib.path import Path

path_0 = Path([
    [1, -1],
    [0, -1],
    [0, -2],
    [1, -2],
])
path_1 = Path([
    [1, 2],
    [0, 2],
    [0, 1],
    [0.999999999999, 1],
])

print(Path.intersects_path(path_0, path_1))

Actual outcome

True

Expected outcome

False 

Note that the two paths are completely separated by a large margin along the y axis, so do not intersect.

Additional observations:

• Choosing different y values for the paths or translating the entire configuration by choosing different x values does not change the result.
• Reducing the precision of the last vertex of path_1 (e.g. making it 1 or 0.9999) changes the result to the expected False.

Matplotlib version

• Operating system: OS X 10.15.1
• Matplotlib version (import matplotlib; print(matplotlib.__version__)): 3.4.2 (bug exists with 3.1.0 as well)
• Matplotlib backend (print(matplotlib.get_backend())): MacOSX
• Python version: 3.7.10

Matplotlib installed using pip in a conda virtual environment (conda activate mpl_bug \ pip install matplotlib) with no other dependencies installed.