The sidebar does not expand when the ToC depth is limited

[petsuter]

Describe the bug
The sidebar does not expand when the ToC depth is limited.

To Reproduce
Steps to reproduce the behavior:

• sphinx-quickstart and select all defaults (Alabaster theme)
• Change / create these files:
• index.rst:

 .. toctree::
   :maxdepth: 1
   
   sub/index

• sub/index.rst:

Sub
===

.. toctree::
   :maxdepth: 1
   
   topic

• sub/topic.rst:

Subtopic
========

test

$ make html

• Open _build/html/index and see everything looks fine. The sidebar on the left shows "Sub". Also the ToC in the middle shows "Sub". All looks OK.
• Click "Sub" and see ToC in the middle shows "Subtopic" as expected. But the problem is the sidebar still only shows "Sub". It did not expand and does not show "Subtopic"!

test-sphinx.zip

Expected behavior
The sidebar should expand, even if :maxdepth: is used.

Environment info

• OS: Windows 10
• Python version: 3.7.1
• Sphinx version: 2.4.1
• Sphinx extensions: None

[petsuter]

This is still a problem in Sphinx 3.1.1

[mgeier]

So you are suggesting that the :maxdepth: setting should simply be ignored w.r.t. the sidebar/globaltoc?

I don't think that's a good idea.

If this were changed, people would come and complain that they specified :maxdepth: but it doesn't work in the sidebar.

Some people will complain either way, but I think the current behavior is more consistent.

[petsuter]

I can not speak for everyone. But to me it is very weird that these two things are coupled together. Why does the local maxdepth affect the global sidebar? Maybe I'm misunderstanding something or am not aware of other options. I expect the sidebar to expand to show the location of the current subpage in the toc, while the ToC in the middle shows just the next level of sub-pages.

I would have guessed that there are maybe some html_theme_options to control the sidebar. But I tried all combinations I could think of for any option I could find and none worked.

I don't suggest changing existing behavior if others think it is working as intended. To me at the moment it seems broken, but I'm happy to change my files and use some other setting that gives the desired result.

[mgeier]

But to me it is very weird that these two things are coupled together.

I agree.
But this is a very different issue (which you can open if you want!).

I would have guessed that there are maybe some html_theme_options to control the sidebar.

This depends on the theme, some theme have options like this.

I've recently added the options globaltoc_collapse and globaltoc_includehidden, but we decided not to add globaltoc_maxdepth before anybody requests it: #7443 (comment)

You might probably be interested in this?

But note that this would be a global setting for the whole TOC. So this might still not be fine-grained enough for your needs?

[petsuter]

Thanks for the pointers.

I now tried changing globaltoc_collapse in the example above, unfortunately using Sphinx v3.1.1 there seems to be no visible change in the output. Or I'm missing something.. Could you maybe give an example?

Do I understand correctly that the desired behavior I described above would be achieved (once the option is implemented) by this configuration:

html_theme_options = {
    'globaltoc_collapse': True,
    'globaltoc_maxdepth': None,
}

As suggested I opened issue #7902 to request it to be implemented.

[mgeier]

Yes, that's how you would use it.

But IIRC, True is already the default for "collapse", so this won't change anything.

And I guess the "unlimited" value for "maxdepth" would be -1, I'm not sure whether None will work (it would probably select the default behavior?).

See https://www.sphinx-doc.org/en/master/templating.html#toctree.

[petsuter]

Ah, -1 was not mentioned on https://www.sphinx-doc.org/en/master/usage/restructuredtext/directives.html#directive-toctree

[tk0miya]

I just post #7925 to add globaltoc_maxdepth :-)