BUG: Correct the previous bug fixing on xlim for plotting

[charlesdong1991]

• xref: Create correct xlim for ts plot and update datetimelike tests #28021 PLT: plot('line') or plot('area') produces wrong xlim in xaxis in 0.25.0 #27993
• tests added / passed
• passes black pandas
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[charlesdong1991]

As I mentioned in issue #28021 , I made a big mistake in finding right bug. The problem is kind of found, which is the ax.set_xlim part, my previous was improper that for datetime-like plotting, then it will look differently.

So with this hotfix, the bug for losing margins on axis mentioned in closed issues can still be fixed for non-datetime data, so plotting will be correct. However, for ts_plot, I still need to find a way to create view margin on xaxis. Restoring only test_datetimelike.py proves that ts plot can still work correctly with datetime formatter. @TomAugspurger

sorry again for this, pls let me know if things are not clear.

[charlesdong1991]

So to illustrate a bit clearer:

this still works correctly since x is not ts:

while this could still have its formatter, only some margin on xaxis will need to be fixed

[TomAugspurger]

Thanks @charlesdong1991. The CI failure is unrelated.

After merging this, are there any issues that need to be re-opened?

[charlesdong1991]

no need to reopen other PRs, the closed issue can still be fixed. The problem only occurs at datetime-like plotting, and with this PR, the view limit can still not be fixed for ts cases. I think I am pretty sure where the issue/bug is, I am still working on a proper solution to fix ts plots. @TomAugspurger

And I am really sorry for this. I quickly opened this PR just to make sure users using ts plots won't be affected/having behivor change while those view limit issues can still be fixed in the new release which is probably today.

[TomAugspurger]

And I am really sorry for this. I quickly opened this PR just to make sure users using ts plots won't be affected/having behivor change while those view limit issues can still be fixed in the new release which is probably today.

No need to apologize :) The release will probably happen today.

Just to make sure I understand the outstanding issues (after merging this).

1. The xlim stuff should be fixed for non-datetime plots
2. There may still be some xlim issues for datetime plots, but it's the same as on 0.25.0?

[charlesdong1991]

Yes, this is very correct. I already updated the issue #28021 description and name to align with the problem. @TomAugspurger

[TomAugspurger]

Great, thanks!

One last question: #27993 was targeted for 1.0. So this shouldn't need to be backported to the 0.25.x branch, right?

[charlesdong1991]

ahh, yeah, should not be to 0.25x . The #27993 is indeed tagged for 1.0.

[TomAugspurger]

OK, thanks again!