Make helpdb.jl and docs as part of build

[pao]

Now that binary builds are a reality, it might be time for us to stop checking in helpdb.jl and make Sphinx a build dependency. We could consider making it an option so you could choose not to build the docs (another Make variable?)

This has implications for the work @wlbksy is doing in #2499.

[wlbksy]

I managed to generate the Chinese version. Personally speaking, I think it's better not to do what you have said. Tell people if they want to modify manual's content, just modify any .rst file in manual/ and stdlib/ .

As for i18n , each language's maintainer can maintain their own helpdb.jl all alone. We can provide a link from here to each translation project.

[wlbksy]

I guess it doesn't matter if helpdb.jl is not so up to date. People who don't know how to generate helpdb.jl can just wait the maintainer do it for them. Let alone there are lots of people who even not want to install python or sphinx.

[pao]

People who don't know how to generate helpdb.jl are most likely going to get Julia from a binary build; either the Windows or Mac binaries from julialang.org, or Linux binaries from their distro. I'd like to be sure that users getting binary builds get the most up-to-date helpdb we can give them.

[nolta]

I've added this to the 1.0 milestones, since i agree we should do this, but not now.

[pao]

That's fine.

[vtjnash]

@pao can we close this?

[pao]

Not until https://github.com/JuliaLang/julia/blob/master/doc/helpdb.jl is an invalid link.

[ViralBShah]

@staticfloat @tkelman What do you guys feel about doing this, and autogenerating helpdb.jl - requiring sphinx as a build dependency. I think we are ready for it.

[ViralBShah]

Of course, non-existence of sphinx should be detected and become a warning, rather than fail the build.

[tkelman]

Worth trying a PR for it, sure. Especially now that we've got the virtualenv stuff hooked up. It's making our build more reliant on Python's package manager working properly, but we can try it out. I haven't timed make -C doc, about how much time would it add to the Travis build? I'd want to skip it (so fail fast or add a simple variable to disable it) on AppVeyor if it takes any more than about 30-60 seconds, to avoid making the queue any longer.

[ViralBShah]

make helpdb.jl is 47 seconds on my mac, which includes getting all the deps and setting up the virtualenv.

[tkelman]

It's about 50 seconds using Cygwin's python, not too bad. I think AppVeyor probably has a win32 python on the path. I'd probably want to disable it on all the CI except Travis, maybe even do helpdb.jl (along with code style / whitespace checks) in a separate build matrix entry.

[ViralBShah]

That seems quite reasonable.

[staticfloat]

Since we have the virtualenv stuff working pretty well now, I think it's definitely worth a shot as a separate build matrix entry. Debian does this with their arch-independent build targets. :P

[tkelman]

see #9553 and #9554

[tkelman]

With #11906 I think this can be closed. AIUI helpdb.jl is now the manually created version, but will be gradually separated out into docstrings at definitions instead.