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

[ludo@gnu.org (Ludovic Courtès)]

Danny Milosavljevic <dannym@scratchpost.org> skribis:

> 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.
>     }
> }

I guess they hamper reproducibility if they’re always created?  In that
case, they need to follow SOURCE_DATE_EPOCH; if OTOH they’re only
created in specific cases that don’t matter much, we can leave them.

>> 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) ...

Yes.

Thanks!

Ludo’.