bug#27563: [PATCH v3 0/2] Make ghostscript reproducible.

[Danny Milosavljevic <dannym@scratchpost.org>]

On Fri, 07 Jul 2017 19:51:10 +0200
ludo@gnu.org (Ludovic Courtès) wrote:

> For CreationDate/ModDate, I think it should honor SOURCE_DATE_EPOCH as
> in
> <https://anonscm.debian.org/git/printing/ghostscript.git/tree/debian/patches/2010_add_build_timestamp_setting.patch?id=e2bf3ad7026afe13636d4937430c3fdae7854078>.

Really?  I've been leaving them off, too.  Especially because of this funny comment in the upstream ghostscript:

/* Initialize the IDs allocated at startup. */
void
pdf_initialize_ids(gx_device_pdf * pdev)
{
...
    /*
     * Acrobat Distiller sets CreationDate and ModDate to the current
     * date and time, rather than (for example) %%CreationDate from the
     * PostScript file.  We think this is wrong, but we do the same.
     */
    {
... proceed to set CreationDate and ModDate to the current time.
    }
}

> For the two UUIDs (and “ID” too?), maybe we can use, say,
> GS_GENERATE_UUIDS; if set to 0 or “no” it’s disable, otherwise it’s
> enabled.

That would look like this:

if (!getenv("GS_GENERATE_UUIDS") || strcmp(getenv("GS_GENERATE_UUIDS"), "0") == 0 || strcmp(getenv("GS_GENERATE_UUIDS"), "no") == 0) ...

> > Also, where would we set it so the build processes of all the other
> > packages actually pick it up?  
> 
> Eventually we can add it to gnu-build-system.scm, but for now, given
> that core-updates is well built, we should add it on a case-by-case
> basis.  I don’t think there are that many packages that produce PDFs,
> but I could be wrong.

Okay :)