Bug report

Bug summary

The interaction of setting axis limits and autoscaling changed in 3.2 with little guidance, introducing unexpected behavior that doesn't always make sense.

Code for reproduction

Here is a plot that looks very different on 3.1.2 and 3.2.1

import numpy as np
import matplotlib.pyplot as plt
f, ax = plt.subplots()
x = np.arange(100)
y = np.random.uniform(-.1, .1, 100)
ax.scatter(x, y)
assert ax._autoscaleYon
ax.set_ylim((-.5, .5), auto=None)

Actual outcome

On 3.2.1

Expected outcome

On 3.1.2

Matplotlib version

• Operating system: macOS
• Matplotlib version: 3.2.1
• Matplotlib backend (print(matplotlib.get_backend())): pylab inline
• Python version: 3.7