J Lovejoy wrote:

(And to give credit where credit is due, Bradley's input during that
challenging "negotiation" was very helpful. :)

😊 … thank you!

I'd written today:

quoted

So, this problem that Thomas notes above is definitely an error by the
SPDX project, *just like* the one that exists for the deprecated “GPL-2.0”

J Lovejoy replied:

To be clear, the GPL-2.0 identifier was never an error by the SPDX team - we
were always very clear as to what it meant/means.

… but notwithstanding a clear definition of a moniker (which I agree indeed
you've made for most SPDX identifiers), if that definition fails to
adequately match historically understanding (and/or fails to take into
account nuances in the document it represents), confusion ensues for users.
Users *were* confused about “GPL-2.0” (remember, we did a small (admittedly
non-scientific) survey at a session at a conference — FOSDEM I think it was?)

Most SPDX *users* won't speak its defined terms fluently; I suspect most of
Linux's licensors (and even most licensees) don't speak SPDX fluently, so
presumably you want SPDX identifiers to have some intuitiveness —
particularly for the use case of linux-spdx, which requires the identifiers
to be *both* human-readable and machine-readable.

This is relevant to the copyleft-next-0.3.1 identifier.  SPDX could define
“copyleft-next-0.3.1” to mean for SPDX purposes: “the text of copyleft-next
without any options in its terms exercised/removed” (— although I note
https://spdx.org/licenses/copyleft-next-0.3.1.html seems to be wholly silent
regarding options exercising/removing).  However, there is currently
confusion — shown in the fact that Thomas still asked:

quoted

quoted

quoted

If I want to remove this option, then how do I express this with a SPDX
license identifier?  Sigh!

… upon noticing this part of copyleft-next:

quoted

quoted

+    Unless I explicitly remove the option of Distributing Covered Works
+    under Later Versions, You may Distribute Covered Works under any Later
+    Version.

Anyway, I'm pointing out SPDX's shortcomings on this point *not* to
captiously admonish SPDX, but rather to point out that any issues with SPDX
identifiers and their formal definitions shouldn't influence a decision about
what licenses are acceptable for inclusion as dual-license options in Linux.

Plus, I remain hopeful that over the long-term, the SPDX project will take
feedback from efforts like linux-spdx to solve the kinds of problems that
have come up in this thread and others.

Finally, I've already started a sub-thread on the copyleft-next list to start
discussing maybe the license (in future versions) shouldn't have this option
anyway (for unrelated policy reasons).  That might yield a side-benefit of
making the problem evaporate entirely for SPDX.  (Anyway, after 25 years of
living with GPL's “-or-later vs. -only” mess — I, for one, am convinced new
licenses like copyleft-next should try very hard to not repeat that mistake.)

 -- bkuhn