Failure with GHC 8.8 / Cabal 2.5 about cabal-doctest HOT 8 CLOSED

This is expected—Cabal-2.5 made a breaking change that affects cabal-doctest. Given that Cabal has a relatively volatile API that changes frequently leading up to new GHC releases, I don't think it's necessarily a good idea to try and have cabal-doctest chase that moving target.

In the meantime, there's a patch in head.hackage which works around the issue. Does that work for you?

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@RyanGlScott, the patch helped, indeed!

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@RyanGlScott, except for its Cabal version bound, though, which is still < 2.5 that breaks 8.8 : -)

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Why not just use --allow-newer?

I'm not willing to relax the upper version bounds until the full GHC 8.8 release, as that invites the possibility that there will be a last-minute change in the 8.8 cycle that breaks existing uploads of cabal-doctest on Hackage. And no, this isn't me just being paranoid—this has actually happened before.

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One problem with --allow-newer is that it seems to require a .project file (i.e. cabal configure doesn't accept it), which isn't how Nixpkgs is set up.

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Nix can jailbreak packages, i.e. remove all bounds?

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Also

% cabal v1-configure --help|grep allow
    --allow-older[=DEPS]                                 Ignore lower bounds in all
    --allow-newer[=DEPS]                                 Ignore upper bounds in all

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@phadej,

Nix can jailbreak packages, i.e. remove all bounds?

..yes, but not within bodies of conditionals. doJailbreak / cabal-jailbreak has no effect on those,

cabal v1-configure...

Aha! That's what I missed from the online docs. Thank you!

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