Re: pgsql: meson: docs: Add {html,man} targets, rename install-doc-*

Hi,

This started at https://www.postgresql.org/message-id/746ba786-85bb-d1f7-b613-57bec35c642a%40dunslane.net
but seems worth discussing on -hackers.

On 2023-11-29 07:20:59 -0500, Andrew Dunstan wrote:
> On 2023-11-28 Tu 21:28, Andres Freund wrote:
> > On 2023-11-23 08:32:21 -0500, Andrew Dunstan wrote:
> > > On 2023-11-20 Mo 20:53, Andres Freund wrote:
> > > > meson: docs: Add {html,man} targets, rename install-doc-*
> > > >
> > > > We have toplevel html, man targets in the autoconf build as well. It'd be odd
> > > > to have an 'html' target but have the install target be 'install-doc-html',
> > > > thus rename the install targets to match.
> > >
> > > This commit of one of its nearby friends appears to have broken crake's docs
> > > build:
> > >
> > > ERROR: Can't invoke target `html`: ambiguous name.Add target type and/or path:
> > > - ./doc/src/sgml/html:custom
> > > - ./doc/src/sgml/html:alias
> > >
> > > See<https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=crake&dt=2023-11-23%2012%3A52%3A04>
> > Ah, I realize now that this is from meson compile html, not 'ninja html'. That
> > explains why I couldn't reproduce this initially and why CI didn't complain.
> > I don't really understand why meson compile complains in this case.  I assume
> > you don't want to disambiguate as suggested, by building html:alias instead?
> >
>
> I've done that as a temporary fix to get crake out of the hole, but it's
> pretty ugly, and I don't want to do it in a release if at all possible.

If we want to prevent these kind of conflicts, which doesn't seem
unreasonable, I think we need an automatic check that prevents reintroducing
them. I think most people will just use ninja and not see them. Meson stores
the relevant information in meson-info/intro-targets.json, so that's just a
bit of munging of that file.

I think the background for this issue existing is that meson supports a "flat"
build directory layout (which is deprecated), so the directory name can't be
used to deconflict with meson compile, which tries to work across all "build
execution" systems.

Prototype of such a check, as well as a commit deconflicting the target names,
attached.

Greetings,

Andres Freund