Re: [Groff] Reproducible dates in HTML/PDF/PS output files?

[Ingo Schwarze]

Hi Werner,

Werner LEMBERG wrote on Wed, Aug 27, 2014 at 03:56:24PM +0200:

>>> I rather suggest to provide this as a configuration option so
>>> that builds that need this functionality can access it.

>> OK.  If it's an environment variable then this comes for free by
>> just setting that variable.  How about the attached patch?

> Basically, it looks good.  However, I'm not convinced that I want to
> *always* suppress timestamps (and a setting in a user's environment is
> more or less permanent).  Instead, I prefer good old command line
> options to control this behaviour.
> 
> Comments?

I'd prefer if groff would never write "CreationDate:" lines.
I don't even see the need to provide an option to write them.

The information contained is misleading in the best case,
because the time at which the document was formatted doesn't
really tell you anything about the document.  In some cases,
it may mislead people to think it was recently modified,
in almost all cases, it is just completely irrelevant.
In some cases, it may endanger privacy - people typically
are sending PDF documents to other people and typically will
not be aware that such information is put in.  In a quite
general sense, software should not facilitate hidden information
leaks, however harmless they may seem in *some* situations.

At least, even if an option to write "CreationDate:" lines
would be provided, it ought to be off by default.  Unrelated
information should only be put into a document if the user
explicitly requests that.  However, who would ever actually
use such an option?  Hardly anybody, i guess, so i don't see
the point in even providing the option.

At the very least, the option ought to be turned off in builds.
In a build, it is always a nuisance and never useful.  Having
reproducible build results is always good, not only when you
specifically require them.  The question "Something is strange
here, did anything change in the build?" typically arises at a
later time.  When you first set up a build, you will hardly
worry about that, so an option to *disable* "CreationDate:"
would be almost useless, people would almost always want it,
but almost never remember in time to set it.

Yours,
  Ingo