Broken release

[hvr]

As can be seen on https://matrix.hackage.haskell.org/package/stdio@1550318928 the stdio-0.1.0.0 release fails to build.

Moreoever, there's another critical quality issue with the stdio-0.1.0.0 release that needs fixing, as can be seen on https://hackage.haskell.org/package/stdio-0.1.0.0/dependencies most dependencies are missing proper version bounds and consequently stdio is not a properly defined cabal package. Please help us ensure a good user experience for users of Hackage/Cabal by the use of the PVP mandated lower&upper bounds in order to reduce the penalty on the Hackage infrastructure as well as to avoid unnecessary extra work for you as well as for us Hackage Trustees!

[winterland1989]

Thanks for reporting this @hvr, but I have a problem here: how can i tell hackage to install libuv (>= 1.14) before continuing build my package? As for the version bound i can spend some time to figure them out.

[hvr]

@winterland1989 use pkgconfig-depends: libuv >= 1.14 :-)

[winterland1989]

@winterland1989 use pkgconfig-depends: libuv >= 1.14 :-)

Thanks! I'll try to revise my cabal file ASAP.

[hvr]

The benfit of using pkgconfig-depends is that you get a more useful solver error:

cabal: Could not resolve dependencies:
[__0] next goal: stdio (user goal)
[__0] rejecting: stdio-0.1.0.0 (conflict: pkg-config package libuv>=1.14, not found in the pkg-config database)

and the cabal solver is able to backtrack as it treats pkgconfig-depends constraints like any other constraint; moreover, in future, we might be able to provide cabal the ability to auto-install C FFI deps on distros which support this. And moroever, pkgconfig-depends also takes care of dealing with include headers or DSOs/library files which are installed into some not-in-searchpath locations, or need special CFLAGS/LDFLAGS.

[winterland1989]

I've uploaded a new version of stdio, please help me revise the cabal file if there's any issue. It seems the pkg-config field didn't solve the issue though.

[hvr]

@winterland1989 the problem is the automatic flag

flag no-pkg-config
  description: Don't use pkg-config to check for library dependences
  default: False

combined with the construct

     if flag(no-pkg-config)
        extra-libraries:   uv
      else
        pkgconfig-depends: libuv  >= 1.14

as I said earlier, one of the benefits of pkgconfig-depends is that it's used by the cabal solver and fully supports backtracking. Consequently, what happens now is that the solver will try to solve for the no-pkg-config variable, and if pkgconfig-depends cannot be satisfied, this means that no-pkg-config must be True.

There's a vague plan to introduce a have_pkgconfig boolean variable, which you can use in conditonals to check whether the tool pkg-config exists, but we don't have that yet.

That being said, did you intentionally use an automatic flag no-pkg-config instead of making it manual? If not, we can revise it to become manual (while keeping it default: False).

[winterland1989]

That being said, did you intentionally use an automatic flag no-pkg-config instead of making it manual? If not, we can revise it to become manual (while keeping it default: False).

Thanks for your explanation, please revise it to become manual (while keeping it default: False). My intention is to provide a fallback for users who don't have pkg-config on their system.

[hvr]

@winterland1989 those users might have to manually toggle that flag via CLI or config files; how many users do you expect to fall into that category? Specifically, on which operating systems do you expect pkgconfig to be missing?

[winterland1989]

@winterland1989 those users might have to manually toggle that flag via CLI or config files; how many users do you expect to fall into that category?

Good question, but I really don't have an answer right now since I just release this package a day before yesterday. On both of my test machines (Ubuntu 18.04 and OSX) pkg-config works all right. I'll add a note to README, suggest those users to manually toggle no-pkg-config flag if pkg-config is not available.

[hvr]

Done: http://hackage.haskell.org/package/stdio-0.1.1.0/revisions/

btw, you could have done this yourself via http://hackage.haskell.org/package/stdio-0.1.1.0/stdio.cabal/edit (but note that the current revision-validation logic allows only to turn automatic->manual but not reverse this)

[winterland1989]

OK, thank you. I'll update my cabal file in this repo later.