Support ads on pallets themes

[davidfischer]

This will allow showing ads on "alabaster-like" themes which includes the pallets themes. It also no longer handles celery as a special case but as another "alabaster-like" theme.

Testing

To test on pallets themes you can:

• Create a local project from the repo https://github.com/pallets/flask/tree/rtd (use rtd branch and Python3)
• Build the docs
• Load the docs and verify that ads are present (assuming you have the ad code)

Screenshots

A sidebar ad

A footer ad

[ericholscher]

Seems like this expands the scope of our ads to a lot more themes. This isn't inherently bad, but we should know that this is the outcome that we're wanting. I imagine it should be fine, but probably worth testing on some of the other common themes.

For example, I believe it will inject on the pypa theme as well: http://pip.readthedocs.io/en/stable/

[ericholscher]

Is this unique to alabaster? It feels like something that would be on almost all themes, as it's inherited from the Sphinx basic theme: https://github.com/sphinx-doc/sphinx/blob/master/sphinx/themes/basic/layout.html#L52-L53

[davidfischer]

Ok. Maybe I need to rethink this. That's a good point.

[humitos]

We are using the same selector to inject the Ads in this line https://github.com/rtfd/readthedocs.org/pull/4499/files#diff-549a0ee75d29b10f27785c6d36e8ce2aR28

So, if the "semantic meaning" of that element from the base theme is what we are selecting, it may makes sense on other themes also.

It would be good to test other themes, though.

[ericholscher]

Yea, it's a common element across most themes with sidebars. Doing that hueristic selector would definitely let us put ads on more themes, but we should just know that's what we're doing :)

[davidfischer]

My immediate goal is to get ads on the pallets themes (which all have different names). Maybe I'll add some constants for "alabaster-like" theme names. From there if we want to iterate and put ads on more themes we can do that in the future.

[humitos]

These changes make sense to me.

It seems that only the heuristic to detect the theme was changes. The heuristic still looks fragile, but we got here with a similar one, so I'd say that it's OK.

[davidfischer]

I reworked this PR a bit to explicitly enumerate the themes rather than using heuristics to detect whether ads would be supported. We might go down that route later, but I don't want to add unintended consequences.

[ericholscher]

Looks good. As a note, I'm +1 in general on using the sidebar heuristic at some point to enable ads on more themes. I think it's going to be an easy way to get most of the common themes, and a lot of the long tail. It's just something we need to do when we have time to message and support it. 👍

[humitos]

I liked the latest changes. Although, it doesn't change the heuristic to decide if it's an ALABASTER-like theme or not. We are still using the same check (> selector on sidebar divs which is from base theme).

I'm 👍 with that, but I understood that you wanted to avoid it for now because it was "too general".

[davidism]

I don't particularly care what it's called internally, but technically Alabaster is Flask-like, not the other way around. And Flask is derived from Basic, so really they're all Basic-like. 😉