[rb-general] Q. Should a tool that implements SOURCE_DATE_EPOCH abort if it can't ensure reproducibility?

[Dan Kegel]

While trying to get a patch implementing reproducible builds upstream to fpm,
I had this review comment from the maintainer:

"If a user is asking for deterministic builds, and the system cannot
produce it, we should abort and error."

(e.g. on a system which ships with non-deterministic ar and tar, and
the user forgot to run
'brew install binutils' or 'port install gnu-tar' or whatever to make
gar and gtar available.)

I looked at https://reproducible-builds.org/specs/source-date-epoch/
but it doesn't
seem to answer this question.  I guess it could go either way; is
SOURCE_DATE_EPOCH
a best-effort flag, or a must-deliver kind of flag?

Can I get a clarification on the spec from the group?

Thanks,
Dan