allow persistent-2.18

[juhp]

This should allow stack to go into nightly and lts25 :-)

Tested locally with stack --resolver nightly --allow-newer.

[juhp]

I don't really understand the failures?

[mpilgrem]

@juhp, the CI errors are caused by the conflict between the package description file (package.yaml) for stack (which is unchanged) and the stack.cabal file.

[mpilgrem]

Relaxing the upper bound on persistent is fine. It is only specified to help users of Cabal (the tool):

# package.yaml

# In order for Cabal (the tool) to build Stack, it needs to be told of the
# upper bound on persistent. See
# https://github.com/commercialhaskell/stack/pull/5677#issuecomment-1193318542
- persistent >= 2.14.0.0 && < 2.18

[mpilgrem]

I have pushed a fixup, as I am about to release Stack 3.9.1 and there is no reason for it not to include this.

[juhp]

Thanks doh (I often forget about package.yaml, sorry not a particular fan of hpack: I just find the workflow quite confusing/exceptional).

(I saw an old related/similar issue #5753 about the upperbound - maybe that helps to explain it)

(I would venture that most people build stack releases with cabal btw: since it is usually not in stackage (-: )