Re: implement a stable 'Last updated' in Documentation

On Tue, Jan 27, Junio C Hamano wrote:

Olaf Hering [off-list ref] writes:

quoted

Several files in Documentation have an unstable 'Last updated' timestamp. The
reason is that their mtime changes every time, which prevents reproducible
builds.

341 technical/api-index.txt: technical/api-index-skel.txt \
342         technical/api-index.sh $(patsubst %,%.txt,$(API_DOCS))
343         $(QUIET_GEN)cd technical && '$(SHELL_PATH_SQ)' ./api-index.sh

388 howto-index.txt: howto-index.sh $(wildcard howto/*.txt)
389         $(QUIET_GEN)$(RM) $@+ $@ && \
390         '$(SHELL_PATH_SQ)' ./howto-index.sh $(sort $(wildcard howto/*.txt)) >$@+ && \
391         mv $@+ $@

399 $(patsubst %.txt,%.html,$(wildcard howto/*.txt)): %.html : %.txt
400         $(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
401         sed -e '1,/^$$/d' $< | \
402         $(TXT_TO_HTML) - >$@+ && \
403         mv $@+ $@

All of them seem to have dependencies so it seems to me that two
builds back to back without actually changing their input would not
re-build anything.  What am I missing???

Per default the files referenced do not exist, so a build from releases
will generate the files. But I agree, perhaps there should be some
refactoring to handle dependencies properly.
In any case, if the 'Last updated' is unavoidable some reference is
required, see my patch in the other mail.

quoted

What file timestamp should be used for them? Likely "../version"?

I tend to think the "Last updated" timestamp taken from the
filesystem timestamp is a bad practice inherited by these tools from
the days back when nobody used any revision control systems.

I'm not sure. The bug is that such 'Last updated' line exists at all in
the default output. Noone asked for it, noone really needs it. And it
makes it impossible to get reproducible builds.
But so far I found no way to avoid the 'Last updated' output. The docs
and google suggest something like :last-updated-time!:, which did not
work for me.

Olaf