Enhancement: Throw a warning during `l3build ctan` if `l3build tag` would make changes

[Skillmon]

As I'm forgetting this frequently, and poor CTAN-maintainers always have to double check my packages, I think it would be nice (also for other users) to throw a warning during l3build ctan if l3build tag was forgotten (so if the usage of l3build tag would lead to different files).

[davidcarlisle]

I assume this would be by essentially doing l3build tag then git status or something to see what changed? Currently l3build ctan (and l3build generally) doesn't assume anything about about the version control in use. There could be a buildctan_hook() or some such that is run at the start of the ctan target that could do whatever you want?

[zauguin]

I don't think that l3build should start trying to determine if something changes, especially since this is in general rather hard.

Also I know some projects (including l3build itself) where such a warning would always trigger (typically because l3build tag adds a new section to the ChangeLog).

[FrankMittelbach]

I agree with @zauguin that this should not be done automatically, but @davidcarlisle 's suggestion to provide a hook for those who want to set up something for their own projects may be a good compromise perhaps?

[Skillmon]

Yes, that indeed sounds like a good idea (and I haven't thought about side effects when l3build tag does more than changing version/date information).