How does cabal select a package from multiple global repositories?

[TerrorJack]

When multiple repositories (e.g. both head.hackage and regular hackage) are present in ~/.cabal/config, a single package might come from different repos, how does cabal decide from which repo is the package picked up? The documentation only says:

If you want, you can configure multiple repositories, and cabal will combine them and be able to download packages from any of them.

The intuition would be selecting from the first repo which contains the package, but it's actually not the case, e.g. when running cabal new-install dlist or cabal new-build for a local package depending on dlist, the dlist package from head.hackage is not picked up, even when head.hackage comes before regular hackage in the global config.

[gbaz]

Note that there is a ghc proposal pending review that addresses the lack of control over this: ghc-proposals/ghc-proposals#115

[23Skidoo]

IIRC it depends on the order the repos are declared in the config file, I think the last one wins.

[phadej]

Yes, last one wins. I'd already implemented a priority field, but that effort is blocked on e.g. #6101 (I really don't want to touch any of ReadP parsers at this point of time).

[fgaz]

i think the recently released active-repositories fixes this