Re: DEP-5 and public domain

[Charles Plessy <plessy@debian.org>]

Le Mon, Aug 02, 2010 at 04:28:23PM +0100, Colin Watson a écrit :
> base-passwd ships passwd.master and group.master files which are
> intentionally public domain.  I received a bug report
> (https://bugs.launchpad.net/ubuntu/+source/base-passwd/+bug/610108)
> noting that "License: PD" isn't valid in DEP-5.  Ideally, I'd like to
> say something like "Copyright: PD" and omit the License field, but of
> course the License field is currently always required.
> 
> Would it be possible to make the License field optional in the case of
> "Copyright: PD", or is there some other better change that should be
> made to accommodate this?

Dear Colin,

I would rather propose the opposite: using ‘PD’ as a special License short name,
because the Copyright field is free-form and therefore not meant to be parsed.
A work in the public domain has no copyright holder, so having no Copyright
field would be appropriate in that case.

Sure, the public domain is not a license, but I think that using ‘PD’ as a
short name in the license field is not a declaration that we think that public
domain is a license, but simply using a structured field to indicate why the
work has no license. In addition, I have found works in the public domain that
contain statements that are usually part of licenses (like warranty disclaimers
or no-endorsment statements), and I tend to add them in the long description. This
is something that would be more difficult to do without the License field.

All in all, one of the fields can be dropped when a work is in the public
domain. The other extreme would be to have ‘PD’ as a value for both, but I do
not think that it brings advantages.

I maintain an experimental branch of DEP-5 in a git repository, where public
domain is indicated through License short names:

http://git.debian.org/?p=users/plessy/license-summary.git

  * **`Copyright`**: One or more free-form copyright statement(s) that apply to
    the files matched by the above pattern.
  
  * **`License`**: Licensing terms for the files listed in the **`Files`**
    field of the same paragraph. If the files have no copyright holders nor
    licence because they are in the Public Domain, the **`License`** field is
    used to indicate this fact. The content of this field is structured in two
    parts.

    * First line: licence identifier(s) in abbreviated format (see *Short names*
      section). If empty, it is given the default value 'other'.
  
    * Remaining lines (optional): Full text of the license(s), or a summary
      notice. If left empty, the content of the first `License` field of the
      machine-readable summary that declares the same short name can be used.


There is no mention that the Copyright field can be dropped, as in this
the version of the DEP, all fields are optional.


Have a nice day,

-- 
Charles Plessy
Tsurumi, Kanagawa, Japan