Re: [PATCH v4 2/2] meson: Deserialize the man pages and html builds

[Fabiano Rosas <farosas@suse.de>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 5/3/23 22:39, Fabiano Rosas wrote:
>> For the documentation builds (man pages & manual), we let Sphinx
>> decide when to rebuild and use a depfile to know when to trigger the
>> make target.
>> 
>> We currently use a trick of having the man pages custom_target take as
>> input the html pages custom_target object, which causes both targets
>> to be executed if one of the dependencies has changed. However, having
>> this at the custom_target level means that the two builds are
>> effectively serialized.
>> 
>> We can eliminate the dependency between the targets by adding a second
>> depfile for the man pages build, allowing them to be parallelized by
>> ninja while keeping sphinx in charge of deciding when to rebuild.
>> 
>> Since they can now run in parallel, separate the Sphinx cache
>> directory of the two builds. We need this not only for data
>> consistency but also because Sphinx writes builder-dependent
>> environment information to the cache directory (see notes under
>> smartquotes_excludes in sphinx docs [1]).
>> 
>> Note that after this patch the commands `make man` and `make html`
>> only build the specified target. To keep the old behavior of building
>> both targets, use `make man html` or `make sphinxdocs`.
>> 
>> 1- https://www.sphinx-doc.org/en/master/usage/configuration.html

Sorry it took me a while to get back to this, I've been caught in
downstream work.

>
> Unfortunately this breaks CentOS 8, which has an older version of ninja:
>
> ninja: error: build.ninja:16369: multiple outputs aren't (yet?) 
> supported by depslog; bring this up on the mailing list if it affects you
>
> This was fixed in ninja 1.10.0.
>

It looks like it would be easier to just wait until all our supported
build platforms reach this version.

Is this CentOS 8 or CentOS Stream 8? I believe CentOS Stream 8 would
drop from our support matrix at the end of this year. And CentOS 8
should have already dropped no? Due to Stream 9 being released in
2021. Unless we do not count Stream as a new version over plain CentOS.

For the dates and versions, I'm looking at:
https://en.wikipedia.org/wiki/CentOS
https://repology.org/project/ninja/versions