Viral as in requiring my code to be compatible with the GPL ecosystem, and in restricting my choice of licenses.
As I gave as my example, I can use a library licensed under the LGPL, and link it with code licensed under the CDDL. I cannot do that with a library licensed under the GPL. With that GPLed library, I'd have to use a license that the GPL is compatible with. So, if I had a product that I wanted to link with both sides, I would need to license my code under a license that is mutually compatible, such as BSD or MIT; I would be restricted from using certain other copyleft licenses.
> Viral as in requiring my code to be compatible with the
> GPL ecosystem, and in restricting my choice of licenses.
By that reasoning, all software licenses are viral. Even the 2-clause BSD license would be viral, because you're not permitted to distribute it combined with code that it's incompatible with.
> As I gave as my example, I can use a library licensed
> under the LGPL, and link it with code licensed under
> the CDDL. I cannot do that with a library licensed
> under the GPL.
That's simple license incompatibility. There are many licenses that are incompatible with the LGPL, and you wouldn't be able to distribute the combined work any more than you could a combined CDDL/GPL work.
> So, if I had a product that I wanted to link with both
> sides, I would need to license my code under a license
> that is mutually compatible
Again, this is true of every copyright license ever created. That's what "incompatible" means.
> By that reasoning, all software licenses are viral. Even the 2-clause BSD license would be viral, because you're not permitted to distribute it combined with code that it's incompatible with.
You're reinventing definitions to suit your argument. The BSD license creates no restrictions on what you can combine it with. The restrictions are defined by to the GPL.
All licenses (except, in some jurisdictions, the public domain) have restrictions. They may be minor, they may be "common sense", but they are still restrictions. The BSD license has restrictions on how code may be redistributed, in particular its requirements regarding attribution and non-endorsement.
If I released some code with a license that said:
This work may not be combined with any work which has a
license containing more than twenty capitalized letters.
Then that license would be incompatible with the BSD license, and it would be illegal to combine the two works.
So if you define "viral" to mean "a license which can be incompatible with other licenses", then the GPL would fit that definition, but so would many other licenses (including the BSD license). Thus, it is not a useful definition.
There is no useful definition of "viral" which covers the GPL but excludes the LGPL.
You're engaging in standard GPL goal-post moving; somehow if you redefine all the words we'll all accept that the GPL isn't a restrictive viral license.
As I gave as my example, I can use a library licensed under the LGPL, and link it with code licensed under the CDDL. I cannot do that with a library licensed under the GPL. With that GPLed library, I'd have to use a license that the GPL is compatible with. So, if I had a product that I wanted to link with both sides, I would need to license my code under a license that is mutually compatible, such as BSD or MIT; I would be restricted from using certain other copyleft licenses.