Explicitely passing an axes to share axis with

[FabricioS]

See issue #1731

[pelson]

I'm not sure this is the most desirable approach. Is is not possible to fix this at the source of the problem (i.e. the change that occurred between 1.1 and 1.2?

[FabricioS]

What is puzzling you exactly ? As mentioned in #1731 the commit introduce a new feature that was as a matter of fact not handled in 1.1. It avoids the redondant use of sharex as a keyword argument and in subplot_kw.

[efiring]

I'm concerned that sharing axes across figures could cause trouble. What happens if the user closes the figure with the specified Axes? Does that cause the figure with the subplot sharing that Axes to crash when redrawn?

[tacaswell]

My understanding of how this worked was that the second axes has a ref to the axis bits and pieces of the first one, so even if you close the first figure, the axis object is not garbage collected.

Experimentally

import matplotlib.pyplot as plt
fig = plt.figure()
ax1 = fig.add_subplot(111)
fig2 = plt.figure()
ax2 = fig2.add_subplot(111, sharex=ax1)

seems to work fine after closing the first figure.

[pelson]

I think we need a test for this PR and then it gets my 👍.

[pelson]

@FabricioS - are you willing to add a test - and then we're good to go.

[mdboom]

@FabricioS: Today is the day we're (hopefully) tagging 1.3.0, so we'll need a test for this PR in order for it to make the cut.

[FabricioS]

Sorry for not answering earlier... What kind of test are you expecting ? Extending test_shared in matplotlib / lib / matplotlib / tests / test_subplots.py ?

[tacaswell]

@FabricioS You still interested in working on this?

I would check that axis objects are the same object in the created axes and the one you passed in.

[pelson]

@FabricioS - I'm going to go ahead and close this PR. It is not to say I wouldn't be comfortable merging this once it has a test, but the number of lingering mpl PRs makes seeing the wood from the trees a little difficult.

Please feel free to re-open once a simple test case exists.

All the best,