Fix sage --docbuild -D

[user202729]

address one of the issues raised in #40290 (comment) . this was originally broken in #39973

The new version did not work exactly as before either, now you need en/ otherwise it wouldn't work, unlike what is explained in the manual. https://doc.sagemath.org/html/en/developer/sage_manuals.html#document-names

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[dimpase]

can you rather base this on #39030 ?
(we probably should just purge this option)

[user202729]

can you rather base this on #39030 ? (we probably should just purge this option)

then how can developers know what are available to build?

[user202729]

@jhpalmieri I tried adding a test in https://github.com/sagemath/sage/compare/2596eb8fcab7312ab2454fce27386dec79f07f82..5ba53639c33bf9ce404d0d172d674c40389c6a88 but the meson builds already doesn't support this. I use meson editable build which still support this (and it works there), and am not too sure how the normal meson build works.

(responding to #39973 (comment))

[dimpase]

can you rather base this on #39030 ? (we probably should just purge this option)

then how can developers know what are available to build?

does the meson docbuild support this kind of granularity? Or it always builds everything in docs (that's my imperssion)

[user202729]

does the meson docbuild support this kind of granularity?

I don't know actually, I just use the meson editable install which does support it.

Or it always builds everything in docs (that's my imperssion)

that would be another undesirable breaking change. Building the whole PDF doc takes an hour, usually when you debug something you just want to build one module.

[dimpase]

isn't meson doing incremental rebuilds? It actually does not matter with incremental rebuilds tell the builder the module name, it's clever enough to know.
(of course here we all have PTSD from the wonderfully dumb current build system, which forces a very wasteful way of throwing perfectly OK build artefacts into the bin all the time)

yes, it comes with a slight disadvantage for a very seldom development process state when nothing is built, but you just want to check one particular file ...

[user202729]

Hm, if they're separate meson build target then it ought to be able to specify the exact target to build on meson/ninja/whatever. Still, it ought to be documented somewhere so that developers such as us figure out how to use it.

[jhpalmieri]

The command sage --docbuild -F doesn't work. It was broken at the same time as the -D option. Please check the output of sage --docbuild -h and make sure that the options work.

Also, the command sage --docbuild all html doesn't work. I am pretty sure that it used to, and it is advertised in the Sage documentation (for example in the meson installation docs).