The Python licensing situation.

Rick Moen rick at
Fri Jun 10 06:17:05 UTC 2011

[snipping the cross-post to license-review, as this subthread 
does not contribute to discussion of a licence for which OSI Approved 
status has been asked.]

Quoting Chuck Swiger (chuck at

> In fact, OSI has approved licenses which forbid distributing modified
> works except as patch files.  This was done to largely to recognize
> that software like DJB's qmail is still OSI open source.

I may regret biting on this one.

1.  Professor Bernstein's commendably generous pre-2007 licence for
qmail was always an interesting edge case.  I don't believe OSI ever
opined that any of his pre-2007 licences, which he put on his Web pages,
for software such as qmail 1.03 or djbdns 1.05, are open source, or am I
misremembering?  (I'm not saying you claimed that; just seeking

2.  What made it an interesting edge case was some of the particulars,
so let's review:

(a) One of his pages,,
stated (pre-2007) that the qmail 1.00, 1.01, 1.02, or 1.03 source tarballs 
with stated MD5 hashes (i.e., unaltered) may be freely distributed.  No 
modification of any sort was authorised for distribution, except as
provided in item (b), next:
(b) A separate page,, stated pre-2007 that
binary compiled derivatives of qmail 1.03 may be redistributed provided
they meet certain of Prof. Bernstein's conformance requirements, e.g., 
being confined within /var/qmail.  A binary package compliant with Prof.
Bernstein's conformance requirements was dubbed a 'var-qmail package'.
(c) Third parties were permitted to mirror and redistribute his
licensing Web pages provided that they agreed to remove any such copies
if he took down his pages, and update them if he updated the pages (I
paraphrase this last item from memory, and apologise in advance for any

Impliedly, item (a) and (c) jointly caused it to be copyright violation
to insert a copy of the licence statements from his Web pages into the
source tarball and distribute that.  It might have even been copyright
violation to include the qmail-1.03.tar.gz tarball into a larger tarball
with licence information or patches or anything else -- and one cannot 
help noticing that nobody did.  The very nicely done qmail-src package
(a set of patches and built scripts) in Debian carefully observed Prof.
Bernstein's pre-2007 requirements by, upon your installing it, fetching
the pristine qmail-1.03.tar.gz from Debian's non-free archive, patching
it to comply with Debian policy and update it generally, and then
compile it into a Debian-compliant binary package (locally, so as not
to distribute anything of Prof. Bernstein's but the pristine
qmail-1.03.tar.gz file).

I slogged through all of that detail in order to demonstrate that 
qmail's pre-2007 licensing was not exactly what one _usually_
contemplates when one speaks of a licence that 'forbids distributing
modified works except as patch files':  Such licences typically do not 
forbid the redistributor from including the licence text with the 
source archive, and do not forbid distribution of derivative works (in
the case of qmail, compiled binaries) that depart from the author's
notions of system architecture and management.

Q Public License (QPL) 1.0, which is still one of the licences under
which Qt is available, is I believe the sort of
modified-works-only-as-patch-files licence OSI wishes to recognise, and
in fact did so.  QPL requires that redistributions of modified source 
furnish the changes 'in a form that is separate from the Software, such
as patches'.  It permits 'machine-executable' (binary) modified copies
provided that the full matching source is available and is itself under
QPL, and that a copy of the licence is included.

I suspect that none of the restrictions in QPL contravene the OSD, but
there are a bunch that qmail's pre-2007 licence does, starting with OSD
#4 ('The license must explicitly permit distribution of software built
from modified source code.')  

So, perhaps Qt under QPL is actually closer to what you had in mind?

I'd consider spending more time on that, except that it all became a
dead letter with Prof. Bernstein's December 2007 announcements
purporting to put most of his published software into the 'public

Rick Moen              "It may be necessary to explain to your younger readers 
rick at    that Mubarak is not a Pokemon."
McQ!  (4x80)                                           -- FakeAPStylebook

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