I tested this and I agree this fixes the problem I reported in #13961.

I also agree this is only a problem for patch. At least, I couldn't
produce a counter-example for conflicts or depends_on.

So, this fixes the case of how to interpret a short name in a spec, as
in spack install intel-tbb @2019. But there remains the case of how
to write a short name inside when.

Intel-tbb has versions 2019, 2019.1, 2019.2, etc. How do I write
patch, or conflicts or depends_on with when that applies to exactly
version 2019 and not 2019.1?

I can't use when='@2019' because that is interpreted broadly, as in
@2019:2019.99.

In this case, there is a workaround: when='@2019:2019.0'. This
works because there is no version 2019.0. But what if there was?
How can I include 2019 but not 2019.0?

Basically, I don't see a way to tell when that a short name is
supposed to mean exactly that one rev, nothing more.
It's too bad that @2019:2019 doesn't work.

But that's really a problem for #8957. Don't let it delay committing
this patch.

Thanks!