On Thu, Nov 16, 2017 at 05:37:50PM -0700, J Lovejoy wrote:

Deprecate the "GPL-2.0" identifier and add the word “only” for GPL
version 2 only, e.g., "GPL-2.0-only"
- this should not be problematic as it does not change the meaning
of the identifier. GPL-2.0 has meant ‘version 2 only’ since the
SPDX License List was born. We are simply adding explicit language
for the identifier. No backwards compatibility issues in terms of
the meaning.
- we can do a “warning” for people using the deprecated identifier
for a period before “GPL-2.0" becomes invalid to give people a
chance to update. This will also encourage people who have been
sloppy to fix their sloppiness.

I think this “deprecation with an eventual removal” approach is part
of all of the proposals, and is not unique to the “coin new
per-version license identifiers” approach.

Keep the + modifier in the license expression language
- this allows use of + with other licenses as always, no change, no
backwards compatibility

I am strongly against having both a ‘GPL-2.0+’ license ID and a ‘+’
operator. I think committing to a ‘GPL-2.0+’ license ID is an
unfortunate but tenable postition. And if we go that way, I'd rather
remove the ‘+’ operator entirely.

I'd be ok with ‘GPL-2.0-or-later’ while preserving the ‘+’ operator
for other licenses. But if a ‘+’ operator is deemed not good enough
for the GPL, which licenses would it be good enough for? This feels
like “we don't know when we'd recommend ‘+’, but didn't have the heart
to kill it”.

Personally, I think the ‘+’ operator *is* good enough for the GPL, but
if that view was universal we wouldn't be adding an or-later license
ID. If we cannot build a consensus around using ‘+’ for the GPL, I'd
rather drop it entirely. My concern with coining license identifiers
for ‘GPL-2.0-or-later’ and similar is the combinatoric increase in
license identifiers, and that's more of an aesthetic concern than a
technical concern (although there are some technical impacts, e.g. the
size of license-list-XML and license-list-data will grow).

Cheers,
Trevor

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