admonitions (note and warn) are not correctly rendered on github

[stefanfoulis]

With rst it is easy to make admonitions for notes and warnings:

.. warning:: don't do this

Using github-markup to render this sort of thing correctly creates this output:

<div class="warning">
    <p class="first admonition-title">Warning</p>
    <p class="last">don't do this</p>
</div>

On github it seems this is just rendered as two normal <p> tags (In gists, the source browser and README.rst).

<p>Warning</p>
<p>don't do this</p>

And that turns out to look like this:

---

---

This makes admonitions useless. Is github doing some extra post-processing of the output? If so, can it be modified to allow this construct to get through.

Just copying the correct code into the browser on a github page in firebug revealed, that stylesheets for this already exist (although they are not that pretty):

---

---

Something similar to the styling on readthedocs.org would be cool:

---

---

[chickenkiller]

The same kind of issues appear for some asciidoc specific renderings which use classes. The root cause is that a HTML sanitization step is done, and among other things, removes class names.

Maybe we should find a way to detect some common classe names per format and give them to Markup so that they are considered harmless, and could also be unified (e.g. Warning, Note are common cases that happen to exist in several formats) so that a CSS style defined by Markup (or higher level layers such as Gollum?) can be applied to them.

[rvanlaar]

.. note :: is still not supported. I'ld this issue to be reopend. See also #72

[beniwohli]

Common @github, this shouldn't be to hard and would be a huge improvement for rendering README's and the like.

[mgaitan]

any progress on this?

[mojavelinux]

AsciiDoc has the same problem. It would be helpful if:

1. there are a set of styles classes in the GitHub stylesheet to use (perhaps there are, but they need to be pointed out)
2. the style classes from the rendered HTML aren't stripped out so that the admonition blocks actually work

[mojavelinux]

Actually, I found these styles in the second stylesheet loaded:

#readme.rst div.admonition,#readme.rst div.attention,#readme.rst div.caution,#readme.rst div.danger,#readme.rst div.error,#readme.rst div.hint,#readme.rst div.important,#readme.rst div.note,#readme.rst div.tip,#readme.rst div.warning{
margin:2em;border:medium outset;padding:1em
}
#readme.rst div.admonition p.admonition-title,#readme.rst div.hint p.admonition-title,#readme.rst div.important p.admonition-title,#readme.rst div.note p.admonition-title,#readme.rst div.tip p.admonition-title{
font-weight:bold;font-family:sans-serif
}
#readme.rst div.attention p.admonition-title,#readme.rst div.caution p.admonition-title,#readme.rst div.danger p.admonition-title,#readme.rst div.error p.admonition-title,#readme.rst div.warning p.admonition-title{
color:red;font-weight:bold;font-family:sans-serif
}

I'm glad they are there, but why make them specific to rst? Why not a standard way of doing admonitions so that any language that has them can use them?

[mojavelinux]

Ah, I see now that @stefanfoulis already figured out that these styles are there using firebug hacking. As it turns out, they are ugly as sin.

[dbrgn]

Please fix this. Warnings are commonly used in README files...

[matthijskooijman]

Hm, just bumped into this issue as well. Without proper support for admonitions, I can't properly write my protocol documentation and I'll have to look for some other way to render them :-S

As for the suggested fix: a whitelist of classnames could be made, but why are CSS class stripped in the first place? To prevent messing up the github layout?

[matthijskooijman]

@github @gjtorikian Would it help if I tried to distill a list of classes that docutils can possibly use in the generated HTML? If I can do anything else to get his issue fixed sooner rather than later, let me know.

[gjtorikian]

They're intentionally being stripped out. It happens in comments here, too:

Warning

don't do this

We have a pretty strict whitelist of what can come through, as defined here: https://github.com/jch/html-pipeline/blob/master/lib/html/pipeline/sanitization_filter.rb

Part of this is done for security reasons. Another part is dealing with supporting class names for multiple markups.

I'm on the fence about closing this as a "won't fix." It's interesting that there are styles in place (probably from years ago). There are actually several RST styles there (for tables and images). And, in general, I'm kind of in favor of showing some light admonition rendering. I'll have to dig around for the rationale and reasoning for stripping out class names from markup. It's not super high on my "list of shit to do" but I can at least guarantee I'll look into it. Hope this helps.

[matthijskooijman]

I was going to argue that writing raw HTML in a comment is different from the rendered HTML, but in the end both of them are user controlled. The actual HTML parts generated by the markup processor could possibly be safe, but since most markup languages have features to include raw HTML as well, there is no way to tell the difference, and sanitizing the generated HTML is the only sensible route.

Stripping class names as part of the sanitizing suprises me a bit, but I can imagine that there sane arguments for that as well.

I wonder if docutils and/or other markup processors would have some configuration options to make them emit a single standardized set of classes, instead of each their own. No time to look into that right now, though.

Thanks for looking into this at any rate, it helps :-)