haskellPackages.postgresql-libpq fails to link on Darwin

[endgame]

Issue description

The macOS build of haskellPackages.postgresql-libpq fails to link in recent nixpkgs; it looks like something's wrong with (at least) the smoke tests:

Preprocessing test suite 'smoke' for postgresql-libpq-0.9.4.2..
Building test suite 'smoke' for postgresql-libpq-0.9.4.2..
[1 of 1] Compiling Main             ( test/Smoke.hs, dist/build/smoke/smoke-tmp/Main.o )
Linking dist/build/smoke/smoke ...
clang-5.0: warning: argument unused during compilation: '-nopie' [-Wunused-command-line-argument]
clang-5.0: warning: argument unused during compilation: '-nopie' [-Wunused-command-line-argument]
Undefined symbols for architecture x86_64:
  "_ASN1_STRING_length", referenced from:
      _verify_peer_name_matches_certificate_name in libpq.a(fe-secure-openssl.o)

Full build.log

Steps to reproduce

This nix expression fails to build on macOS:

let
  nixpkgs = import (builtins.fetchTarball {
    url = "https://github.com/NixOS/nixpkgs/archive/5632aad4739c2fc342ea280cee47b5213f799491.zip";
    sha256 = "0zfzfhmbshdkgi5pl5sxh1l8r8m13vwgwsyafbixvc6pcc4sdrh3";
  }) {};
in
  nixpkgs.haskellPackages.postgresql-libpq

This is a regression: i can successfully enter a nix-shell using this package if I use an 18.09 channel.

Technical details

nix-info -m:

 - system: `"x86_64-darwin"`
 - host os: `Darwin 17.7.0, macOS 10.13.6`
 - multi-user?: `no`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.1.3`
 - channels(che347): `"nixpkgs-19.03pre159614.f52b7f5c345, nixpkgs-18.09-darwin-18.09pre152973.012b9e6c219"`
 - nixpkgs: `/Users/che347/.nix-defexpr/channels/nixpkgs`

I am not sure how best to proceed. Please let me know if I can provide more useful information.

[alyssais]

Broken since ab1a64f

[endgame]

That missing

   librarySystemDepends = [ postgresql ];

line looks ominous. I'll investigate and see how things go on my friend's mac.

[ranjanibrickx]

I have the same issue as well.

nix-info -m
 - system: `"x86_64-darwin"`
 - host os: `Darwin 17.7.0, macOS 10.13.6`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.1.3`
 - channels(ranjanin): `"darwin, nixpkgs-19.03pre159739.3ae0407d3c9"`
 - channels(root): `"nixpkgs-19.03pre158225.fccfc775d11"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixpkgs`

[endgame]

I am trying to fix this on this branch: https://github.com/endgame/nixpkgs/tree/haskell-postgres-libpq

In 81ff25d23fcbf783ff9337c573e76e64e959e874 I add a postgresql.lib dependency to haskellPackages.postgresql-libpq, but that causes the build to fail earlier in building postgresql. These appear to be the critical lines:

error: /nix/store/p1zg3dnaaglqm34pq12ynfa2pc3r2lq8-cctools-port-895/bin/ranlib: can't open file: libpgtypes.a (No such file or directory)
ar: internal ranlib command failed

build.log

[LnL7]

These are all the compiler flags https://gist.github.com/LnL7/3f7f7e00a2c6b2ec15d27e1be139402f, there are no references to openssl there tho.

[LnL7]

Ah I think I see what's going on here, adding postgresql.lib before postgresql fixes the issue. I think it's finding the static libraries first and tries to use those instead. I see some stuff in the postgresql expression that's supposed to remove the static libraries.

There's a good chance that making this also handle *.dylib files will fix the issue without the workaround in the haskell package.
https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/sql/postgresql/default.nix#L73-L75

[endgame]

Thanks @LnL7 , I'll make a PR to use ${stdenv.hostPlatform.extensions.sharedLibrary} instead of .so in that script.

[endgame]

Is it correct to close an issue after the PR to fix it hits staging, or when it hits master?

[LnL7]

Github will do that automatically and it would take some effort to track when staging is merged back so the issue would often stay open otherwise. However for issues with a high impact it's sometimes opportune to keep them open to make them more discoverable and avoid people creating duplicates.

[endgame]

Thanks. For some reason this hasn't self-closed, so I'll do that now.

[endgame]

This still isn't working correctly - nixpkgs on darwin is not removing libpq.a despite libpq.dylib showing up in .lib

I will investigate.

[endgame]

Disregard, I think my channel wan't updating for some reason.