Updated built-in sphinxify routine to support proposed changes in Sage

[embray]

This is a change needed in order to support changes I'm proposing to Sage in https://trac.sagemath.org/ticket/21732

Those changes haven't been approved yet though, so obviously this PR should not be merged until something is finalized in that Trac ticket. Ideally, sagenb should probably not rely on Sage, or SAGE_DOC_SRC/SAGE_SRC at all for this, and I'd be in favor of a more extensive PR for sagenb to just include its own Sphinx configuration files for this purpose. But for now this is the simplest solution.

[kcrisman]

Well, ideally sagenb would be merged back into Sage proper. This seems fine otherwise. I suppose you could import SAGE_SRC only if necessary but probably it doesn't matter.

[embray]

Well, ideally sagenb would be merged back into Sage proper

I disagree that that is ideal, but I guess this is not the place to discuss that.

[jdemeyer]

sphinxify has been move to Sage now, see src/sage/misc/sphinxify.py, why not use that instead and fix it in Sage?

[embray]

IIRC in the ticket I linked to in the PR description I did fix it there. This PR was to apply the same fix to the copy here. I think there were reasons there was a separate copy being maintained in sagenb (perhaps for backwards-compatibility with older Sage versions).

[jdemeyer]

I think there were reasons there was a separate copy being maintained in sagenb

I don't think that there are any such reasons, we don't expect newer versions of SageNB to work with older versions of Sage.

[embray]

Maybe what I was actually thinking of was all this stuff:

sagenb/sagenb/misc/sphinxify.py

Line 162 in 9fb1ab5

def generate_configuration(directory):

[jdemeyer]

If you read the PR description again, you will notice that merging this was a very bad idea.

This should be reverted (unless somebody has a very good reason why it should be merged anyway).