generate-summary seems to cache old result

[Anton-Latukha]

During: #1315 I noticed that after first run:

cabal v2-run hlint -- --generate-summary stoped to represent hlint.yml changes into hints.md. It seems to use some old cache for generation of hints.md. (I note that in the fx commit), it essentially broke on me - changes in yaml not appear in hints.md (I imagine) because of some caching somewhere, deleting hints.md does not help - generation still produces old variant with old wording & without rule updates etc.. .

---

tech details

* The Glorious Glasgow Haskell Compilation System, version 8.10.7

* cabal-install version 3.6.2.0

* compiled using version 3.6.2.0 of the Cabal library

* hackage.haskell.org,2021-11-11T03:14:22Z

Patch branch is based on 8e10b51, user first noted it in 441049c during PR work.

[zliu41]

This seems like either a Cabal bug or a GHC bug. I opened a Cabal issue: haskell/cabal#7862
A workaround is to cabal clean before generating the summary. Then you should get the up-to-date summary.

[Anton-Latukha]

Thank you. Would close after recheck & enough time for people who hit this to see the solution, especially because it goes up into the TH realm.

How one starts to debug this?

[zliu41]

I previously knew that hlint.yaml is loaded at compile time. So when I noticed that modifying hlint.yaml doesn't trigger Cabal to recompile anything, that points to a Cabal/GHC issue.

By the way, according to the comments in haskell/cabal#7862, another workaround is to stop using wildcards in extra-source-files, so I'll make that change which should prevent this problem from occurring in the future.