Re: [PATCH] doc: make HTML manual reproducible

["Martin Ågren" <martin.agren@gmail.com>]

On Tue, 1 Dec 2020 at 16:41, Todd Zullinger <tmz@pobox.com> wrote:

> Arnout Engelen wrote:
> > This makes sure the generated id's inside the html version of the
> > documentation use the same id's when the same version of the
> > manual is generated twice.

Thanks for this. Your mail still hasn't reached me through the list, so
I'm replying to Todd's reply here.

Looking through the word-diff of the resulting user-manual.html, I see
basically three changes. I've applied some light copy-editing to try to
make them more readable (the lack of spaces means the notion of "word"
diff is a bit off). Do you also have these three changes?

  1. <a name=[-"idp1"-]{+"id-1"+}></a>Git User Manual</h1>

  2. <a href=[-"#idp2"-]{+"#id-1.2"+}></a>

  3. <a name=[-"idp2"-]{+"id-1.2"+}></a>

These names and links don't strike me as particularly useful. But even
so, reproducibility makes sense. I guess you're not really after linking
to these, but want to have binary-identical user-manual.html when
building from the same commit?

> > @@ -380,7 +380,7 @@ SubmittingPatches.txt: SubmittingPatches
> >       $(QUIET_GEN) cp $< $@
> >
> >  XSLT = docbook.xsl
> > -XSLTOPTS = --xinclude --stringparam html.stylesheet docbook-xsl.css
> > +XSLTOPTS = --xinclude --stringparam html.stylesheet docbook-xsl.css --stringparam generate.consistent.ids 1

Nit: Maybe add a new line

  XSLTOPTS += --stringparam generate.consistent.ids 1

instead to keep within 80 characters.

> I think this would raise the minimum supported version of
> docbook-xsl to 1.77.1.  That might be fine, but we'd
> probably want to make sure it doesn't negatively impact
> OS/distributions which build the docs as a likely group who
> care about reproducible builds.  And we'd want to update the
> requirement in INSTALL, of course.

Thanks for digging out the version number. Agreed that this change
should be reflected in INSTALL.

> The minimum docbook-xsl version was raised from 1.73 to
> 1.74, in 5a80d85bbe (INSTALL: drop support for docbook-xsl
> before 1.74, 2020-03-29).  That change was discussed in
> <cover.1585486103.git.martin.agren@gmail.com>¹.

As mentioned there, it's not like I went out and tested with 1.74. So
whether we *actually* support 1.74 right now is anyone's guess.

> AFAICT, the generate.consistent.ids param was added in
> docbook-xsl-1.77.1 which was released in June 2012.  The
> commit which added it is 74735098e (New param to support
> replacing generate-id() with xsl:number for more consistent
> id values., 2011-10-24).
>
> In any case, a minimum of 1.77.1 is present in the supported
> releases of CentOS/RHEL and Debian/Ubuntu, at least (most
> have 1.79.x).  Those are certainly not the only systems Git
> cares about; they're simply the systems with which I am at
> least mildly familiar.

Seems to me like we can go with a change like this. If you're on a
pre-1.77.1 system and want user-manual.html, but don't want to update
your tool chain, you should still be able to clone the "htmldocs" repo.
I'm not sure exactly where the cut-off point is, but I think moving up
to mid-2012 should be ok.

Martin