Re: Missing makefile dependencies

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Subject: Re: Missing makefile dependencies
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Hi Richard,

At 2026-07-28T14:15:12+0100, Richard Purdie wrote:
> I reported some build races a while ago. It appears there are still
> some issues left and they weren't an isolated problem. I tried to make
> a simple reproducer for the original problem I ran into but ran into
> further problems. To illustrate what I saw (on a fresh checkout of
> groff from git):

[snipping the initial Gnulib-produced header issue with which I
requested aid]

>  make doc/groff-man-pages.pdf
>   GROFF    doc/groff-man-pages.pdf
> /groff/groff: error: couldn't exec preconv: No such file or directory
> pdfmom: fatal error: test-groff exited with status 16
> make: *** [Makefile:19752: doc/groff-man-pages.pdf] Error 1
> make: *** Deleting file 'doc/groff-man-pages.pdf'
>=20
> which leads me to believe this is needed:
>=20
> diff --git a/doc/doc.am b/doc/doc.am
> index 9898a19d8..a30b3e599 100644
> --- a/doc/doc.am
> +++ b/doc/doc.am
> @@ -289,7 +289,7 @@ $(DOC_GMP_COVER_PAGE): $(doc_srcdir)/groff-man-pages-=
cover.groff.in
> =20
>  doc/groff-man-pages.pdf: $(GROFF_MAN_PAGES_ALL) \
>    $(DOC_GMP_COVER_PAGE) \
> -  eqn pic tbl pdfmom \
> +  eqn pic tbl pdfmom preconv \
>    $(TMAC_PACKAGE_MAN) $(TMAC_PACKAGE_MDOC) font/devps/freeeuro.pfa
>         $(GROFF_V)$(DOC_PDFMOM) -K utf-8 -pet -mandoc -dHF=3DHB -rC1 \
>           -rCHECKSTYLE=3D3 -Tpdf $(groffmanpagesoption) \
> @@ -298,7 +298,7 @@ doc/groff-man-pages.pdf: $(GROFF_MAN_PAGES_ALL) \
>           $(tmac_srcdir)/sv.tmac $(GROFF_MAN_PAGES2) \
>           $(tmac_srcdir)/en.tmac $(GROFF_MAN_PAGES3) > $@
> =20
> -doc/groff-man-pages.utf8.txt: $(GROFF_MAN_PAGES_ALL) eqn pic tbl \
> +doc/groff-man-pages.utf8.txt: $(GROFF_MAN_PAGES_ALL) eqn pic tbl preconv=
 \
>    $(TMAC_PACKAGE_MAN) $(TMAC_PACKAGE_MDOC)
>         $(GROFF_V)$(DOC_GROFF) -K utf-8 -pet -Tutf8 -mandoc \
>           -rCHECKSTYLE=3D3 $(GROFF_MAN_PAGES1) \

Good catch.  preconv(1) is certainly required, as groff_mmse(7) is in
the set of documents being read by the pipeline.

I'll fix this for 1.25.0.rc2.

You gave me an idea, which I've filed as
<https://savannah.gnu.org/bugs/?68574>.

> but there may be further missing dependencies. I'd also note:
>=20
> $ make doc/automake.pdf
> [...]
>   GROFF    doc/automake.pdf
> groff/groff: error: couldn't exec preconv: No such file or directory
> groff/groff: error: couldn't exec pic: No such file or directory
> groff/groff: error: couldn't exec eqn: No such file or directory
> pdfmom: fatal error: test-groff exited with status 24
> make: *** [Makefile:19637: doc/automake.pdf] Error 1
>=20
> which is probably:
>=20
> diff --git a/doc/doc.am b/doc/doc.am
> index 9898a19d8..47ef1621c 100644
> --- a/doc/doc.am
> +++ b/doc/doc.am
> @@ -143,7 +143,7 @@ EXTRA_DIST +=3D $(DOCFILES_NOINST)
>  EXTRA_DIST +=3D doc/automake.mom
>  docpdfdocdir =3D $(pdfdocdir)
>  nodist_docpdfdoc_DATA =3D $(PROCESSEDDOCFILES_PDF)
> -doc/automake.pdf: doc/automake.mom pdfmom $(TMAC_PACKAGE_MOM)
> +doc/automake.pdf: doc/automake.mom pdfmom pic eqn preconv $(TMAC_PACKAGE=
_MOM)
> =20
>  # GNU PIC html documentation, installed in $(htmldocdir)
>  # Other pic*.html files are installed by the local rule
>=20
> to fix. Those are just the ones we've run into though.

The foregoing is an interesting case.  We don't actually need preconv,
eqn, _or_ pic to generate "automake.pdf".

"automake.mom"'s only non-ASCII character appears in a _roff_ comment.

https://cgit.git.savannah.gnu.org/cgit/groff.git/tree/doc/automake.mom?h=3D=
1.25.0.rc1#n3

It uses no preprocessor tokens, either (`TS`, `EQ`, `PS`, `[`).

Yet pdfmom(1), in an effort to be helpful I suppose, brings the full
power of its battle station to bear on poor old Alderaan.

$ make V=3D1 doc/automake.pdf
/usr/bin/mkdir -p `dirname doc/automake.pdf` \
&& LC_ALL=3DC GROFF_COMMAND=3Dtest-groff GROFF_COMMAND_PREFIX=3D GROFF_BIN_=
PATH=3D"/home/branden/BUILD/groff-1.25.0.rc1" /home/branden/BUILD/groff-1.2=
5.0.rc1/pdfmom -F/home/branden/BUILD/groff-1.25.0.rc1/font -F/home/branden/=
BUILD/groff-1.25.0.rc1/font -M/home/branden/BUILD/groff-1.25.0.rc1/tmac -M/=
home/branden/BUILD/groff-1.25.0.rc1/tmac -M./contrib/mom -K utf8 -p -e -t -=
wall -b -P-W doc/automake.mom >doc/automake.pdf
/home/branden/BUILD/groff-1.25.0.rc1/groff: error: couldn't exec preconv: N=
o such file or directory
/home/branden/BUILD/groff-1.25.0.rc1/groff: error: couldn't exec pic: No su=
ch file or directory
/home/branden/BUILD/groff-1.25.0.rc1/groff: error: couldn't exec tbl: No su=
ch file or directory
/home/branden/BUILD/groff-1.25.0.rc1/groff: error: couldn't exec eqn: No su=
ch file or directory
pdfmom: fatal error: test-groff exited with status 16
make: *** [Makefile:19555: doc/automake.pdf] Error 1
make: *** Deleting file 'doc/automake.pdf'

However, I have to use a groff-less chroot to reproduce this problem.
If I don't, the document build escapes from its enclosure and finds the
preprocessors installed in the host environment.

That's not good.

I perceive 3 independent lines of attack.

1.  As I mentioned earlier this month, we don't need to use pdfmom(1)
    _at all_ to generate "automake.pdf".

    https://lists.gnu.org/archive/html/groff/2026-07/msg00019.html

    I can take care of this in the short term for 1.25.0.rc2.

2.  Make "test-groff" set "PATH=3D$GROFF_BIN_PATH" and see what, if
    anything, breaks.  Since "test-groff" is just a wrapper for "groff",
    and "groff" builds a pipeline _only_ of programs that are produced
    as part of a groff build, this _should_ work.  But I know better
    than to bet money on it.  I'll file a Savannah ticket for this issue
    and will plan to work on it early in the 1.26 development cycle.

    If it works out, it should go a good distance toward solving a
    problem I think Deri observed with groff documentation artifacts
    getting build not necessarily with the build's groff programs.

3.  pdfmom(1)'s mission needs to be put on a diet.[ibid.]  It seems to
    have mutated into a tool with no charter except to get documents
    built with brute force, multi-pass processing whether they need that
    or not, throwing several preprocessors at them whether needed or
    not, and, recently, sprawling beyond its initial goal of easing
    production of PDF documents using the mom(7) macro package to
    generating general "roff" documents, not necessarily using mom(7)
    (see its `--roff`(!) option) or being produced in PDF format.

    In other words, having disposed of one Perl script called
    groffer(1) in groff 1.23.0, we are metamorphosing another Perl
    script into its replacement.

    Enough!

    I have some notions of a new approach but they'll need to cook a
    while longer.  I have no concrete timeline for working this out.

> It was bad enough someone suggested we should patch groff:
>=20
> --- a/Makefile.am~	2026-05-15 13:23:08.000000000 +0100
> +++ b/Makefile.am	2026-05-15 13:29:17.053867035 +0100
> @@ -556,15 +556,0 @@
> -include $(top_srcdir)/contrib/chem/chem.am
> -include $(top_srcdir)/contrib/eqn2graph/eqn2graph.am
> -include $(top_srcdir)/contrib/gdiffmk/gdiffmk.am
> -include $(top_srcdir)/contrib/glilypond/glilypond.am
> -include $(top_srcdir)/contrib/gperl/gperl.am
> -include $(top_srcdir)/contrib/gpinyin/gpinyin.am
> -include $(top_srcdir)/contrib/grap2graph/grap2graph.am
> -include $(top_srcdir)/contrib/hdtbl/hdtbl.am
> -include $(top_srcdir)/contrib/install-font/install-font.am
> -include $(top_srcdir)/contrib/mm/mm.am
> -include $(top_srcdir)/contrib/mom/mom.am
> -include $(top_srcdir)/contrib/pic2graph/pic2graph.am
> -include $(top_srcdir)/contrib/rfc1345/rfc1345.am
> -include $(top_srcdir)/contrib/sboxes/sboxes.am
> -include $(top_srcdir)/doc/doc.am
>=20
> so that we could avoid these issues!

That's not the "right" fix, but I sympathize.

> https://git.openembedded.org/openembedded-core/commit/?id=3D9deeb7474b258=
6eb031e4f00a644aed9ccf8cb19
>=20
> I wasn't sure if there was a better way to avoid the bits of the build
> we don't really need just to get the tools?

We have a ticket for this, but you won't _need_ a "tool-only" build if
we can keep wrappers like "test-groff" and "pdfmom" from going hunting
for tools outside of the build environment when they're run inside it.

https://savannah.gnu.org/bugs/?68554

Regards,
Branden

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