[bug#70169] [PATCH v2 09/12] maint: Remove %%CreationDate from generated EPS files

["Ludovic Courtès" <ludo@gnu.org>]

Janneke Nieuwenhuizen <janneke@gnu.org> skribis:

> * doc/local.mk (.dot.eps, png.eps): Remove %%CreationDate.  Split single shell
> command into separate recipe lines, prefixed by $(AM_V_at).
>
> Change-Id: I5a03485c19c72f0c46411815c51290e52a8e5399
> ---
>  doc/local.mk | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/doc/local.mk b/doc/local.mk
> index c355bec8d7..60e36091ce 100644
> --- a/doc/local.mk
> +++ b/doc/local.mk
> @@ -152,12 +152,16 @@ DOT_OPTIONS =					\
>  	mv "$(srcdir)/$@.tmp" "$(srcdir)/$@"
>  
>  .dot.eps:
> -	$(AM_V_DOT)$(DOT) -Teps $(DOT_OPTIONS) < "$<" > "$(srcdir)/$@.tmp"; \
> -	mv "$(srcdir)/$@.tmp" "$(srcdir)/$@"
> +	$(AM_V_DOT)$(DOT) -Teps $(DOT_OPTIONS) < "$<" > "$(srcdir)/$@.tmp"
> +	$(AM_V_at)grep -v ^%%CreationDate: "$(srcdir)/$@.tmp" > "$(srcdir)/$@.tmp2"
> +	$(AM_V_at)rm -f "$(srcdir)/$@.tmp"
> +	$(AM_V_at)mv "$(srcdir)/$@.tmp2" "$@"

Apparently ‘dot’ (GraphViz) does not emit a ‘CreationDate’ header.

Should we drop this change and add a line like this above the ‘mv’ line:

  @if grep -q CreationDate "$@.tmp"; then false; else true; fi

to be on the safe side?

>  .png.eps:
> -	$(AM_V_GEN)convert "$<" "$@-tmp.eps"; \
> -	mv "$@-tmp.eps" "$@"
> +	$(AM_V_GEN)convert "$<" "$@-tmp.eps"
> +	$(AM_V_at)grep -v ^%%CreationDate: "$@-tmp.eps" > "$@-tmp2.eps"
> +	$(AM_V_at)rm -f "$@-tmp.eps"
> +	$(AM_V_at)mv "$@-tmp2.eps" "$@"

Looking into the code of ImageMagick, I see:

--8<---------------cut here---------------start------------->8---
        timer=GetMagickTime();
        (void) FormatMagickTime(timer,MaxTextExtent,date);
        (void) FormatLocaleString(buffer,MaxTextExtent,
          "%%%%CreationDate: %s\n",date);
--8<---------------cut here---------------end--------------->8---

where ‘GetMagickTime’ honors ‘SOURCE_DATE_EPOCH’.  Should we set
‘SOURCE_DATE_EPOCH’ and avoid the ‘grep’ trick?

OTOH, an argument to keep this patch as-is is that it’ll resist to
changes in ImageMagick/GraphViz.  So maybe the comments above aren’t
that relevant.

Ludo’.