clarify "configure" messages from Cabal

[geekosaur]

Template Α: This PR modifies cabal behaviour

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

[geekosaur]

I used template A because error messages are user-facing. I'm not sure how to test these though, as the only way I know to trigger them is a possible cabal-install bug suffered by @Kleidukos around a week ago.

[Kleidukos]

I have this bug when using cabal-head but not a released version. Thanks for handling this @geekosaur

[geekosaur]

Sadly I haven't fixed the actual bug, just made the error message a little less confusing. I assume there's a mismatch between what Distribution/Simple/Configure.hs serializes to setup-config and what it expects when it reads it back in later.

[geekosaur]

BTW @Kleidukos can you file a bug about your error so we have a record of it? I may or may not be able to get to it this weekend and I'll be gone on Monday. AFAICT you only mentioned it on Matrix.

[andreabedini]

LGTM, is Setup clear enough in context?

[geekosaur]

It's used in a few other places (mostly comments), and it could be Setup.lhs instead of Setup.hs.

[geekosaur]

I still don't see a bug corresponding to this, and have no idea whether the original problem still exists, nor how I would go about testing this.

[ulysses4ever]

@geekosaur do you have a plan for this? SHould it be turned into non-draft?

[Kleidukos]

I completely missed this. I'll see if it's still a thing.

[geekosaur]

As far as I'm concerned it's ready to go. But all it does is change some messaging, since Cabal confusingly tells you that you need to reconfigure (which is strictly correct, but if you're using cabal-install then "reconfigure" means something else entirely).