adding a BUILD_EXCLUSIVE_KERNEL... blacklist?

[anbe42]

Right now we have BUILD_EXCLUSIVE_KERNEL as a regex that whitelists kernel versions. With the recently added BUILD_EXCLUSIVE_KERNEL_MIN/MAX that whitelist regex probably gets less used. But sometimes I'd rather like to blacklist a single (or a few) incompatible kernel versions ... so a regex would still be nice, but negating it into a whitelist makes it unreadable, e.g. ^([1-4]\.|5\.[0-46-9]\.|5\.[1-9][0-9]|[6-9]\.|[1-9][0-9]).
I might add such a directive, but I cannot come up with a good name for it.
And we can't simply prefix the BUILD_EXCLUSIVE_KERNEL value with '!' to negate its meaning, as the would break usage on older dkms versions.

[evelikov]

Negating BUILD_EXCLUSIVE that means we want a BUILD_REQUIRES right?

Overall I like the idea, but I'm a little concerned about:

• conflicting configuration - doable but needs documentation and tests, which can raise the complexity
• forward and backward compatibility - say I create a new dkms module that uses the new token and some users try it against older dkms

Latter is a bit moot point, since we don't do much of that atm. The former seems far more relevant IMHO.

[anbe42]

I would see it more as BUILD_EXCLUDE, but that's visually very similar ..

I don't see a potential for conflicting configuration. All BUILD_EXCLUSIVE_* settings define some contraints, and if a kernel does not match any one of them it is thrown out.

New directives will be ignored by older dkms, we just shouldn't change the meaning of the previously existing ones ...
The modules will simply fail to build with the older dkms since it was impossible to express the constraint to exclude that kernel at that time.

[evelikov]

I may or may not have misread "exclusive" as "exclude" in the first place 😛

Speaking of conflicting configuration, let's consider BUILD_EXCLUSIVE=5.1 and BUILD_EXCLUDE=5.*. This should result in 0 modules handled, correct? It is somewhat of a nonsensical config, so I'm wondering if that should be success, skip or failure? Do we want to inform the user about the potential typo/miss-config?