Copyright information in headers

[Ian Booth]

Hi folks

The question recently came up in reviews as to whether we should be updating the
date in the copyright statement in the file header when we make a change to the
code in that file. I sought clarification from Robie Basak, who previously had
provided input on licensing issues and compliance for getting Juju included in
trusty. Below is what he said.

TL;DR;
It doesn't really matter, we just need to agree on a policy. It is suggested
though that we do update the date when we make a change. Agree?

<snip>
> 
> What's our policy for dates in copyright headers?
> 
> // Copyright 2012, 2013 Canonical Ltd.
> // Licensed under the AGPLv3, see LICENCE file for details.

>From the point of view of acceptability for Ubuntu, it doesn't
particularly matter, and I don't believe it'll cause any issue for us
whatever you do here. I'll certainly be happy to upload whether or not
you update the date.

I'll try to explain my perspective on this, but I'm not entirely
confident that there isn't something I'm missing for the broader
picture, so note that I Am Not A Lawyer, etc.

> For the above, do we need to add 2014 if we modify the file this year?
> Or is the date just meant to be the year the file was first published?

I think it's meant to be the sum of all the copyright claims on the
file. So if you add some new code, you have a copyright claim on the new
code in the newer year in which you made it.

AIUI, the purpose of the date is that since copyright expires
(theoretically, anyway), updating the date updates the copyright claim,
which would give us more control in the (eventual) event that copyright
expires.

In practice, IMHO this is never going to matter since nobody is going to
care about the copyright on a piece of software that is that old anyway.
But I suppose laws could change, so the right thing to do would be to
add a new year whenever you make a change in a new year on a per-file
file basis. BTW, it's common to fold "2012, 2013, 2014" to just
"2012-2014".

But I don't particularly care for upload purposes.