@c0bw3b, thanks for your PR! By analyzing the history of the files in this pull request, we identified @fpletz, @wkennington and @edolstra to be potential reviewers.

$ nix-build --expr 'with import <nixpkgs> {}; callPackage ./localnixpkgs/pkgs/development/libraries/nghttp2/default.nix {}'
was successful and created the derivation /nix/store/1r7qclqb7rbl16hdlmbw0ijpa1vznl61-nghttp2-1.17.0

$ nix-build --expr 'with import <nixpkgs> {}; callPackage ../localnixpkgs/pkgs/development/libraries/nghttp2/default.nix { openssl=pkgs.openssl_1_1_0; libxml2=pkgs.limxml2; jansson=pkgs.jansson; jemalloc=pkgs.jemalloc; }'
was successful and created the derivation /nix/store/ybnfgsa5f27l6clmbfccj4a5a2s70ks0-nghttp2-1.17.0

Building on 16.09-small

$ nixos-version
16.09.1240.c43a79e (Flounder)

Staged.

Hello,

Looking back at the nghttp2 Nix definition : the postPatch action is not needed anymore since it has been patched upstream a long time ago. See :

• nghttp2/nghttp2@e2c0a3e
• https://github.com/nghttp2/nghttp2/blob/v1.17.0/configure.ac#L420

I also noticed that the optional dependencies [ jansson boost libxml2 jemalloc ] will never be used even if passed as arguments. They are not added to the build inputs if not null.

@vcunat you can judge if the correction (and another mass-rebuild) is worthwhile at this point.

Thanks to some canonicalization during evaluation, it's only mass-rebuild on Darwin and Hydra's currently idling on that platform.

I tried to get rid of curl in the darwin stdenv a while ago, but cmake does not want to build without it.

@vcunat
I'd rather keep the possibility of building with those inputs.
It would allow users to build the libnghttp2_asio C++ library (needs boost). Or reduce heap fragmentation with long-running processes when using nghttpd or nghttpx on a webserver (my own case -- needs jemalloc).

Replacing buildInputs = [ openssl libev zlib ]; with the following should do the trick :

  buildInputs = [ openssl libev zlib ]
    ++ optional (!isNull jansson) jansson
    ++ optional (!isNull boost) boost
    ++ optional (!isNull libxml2) libxml2
    ++ optional (!isNull jemalloc) jemalloc;

We would need a different approach, as by default all parameters are passed as non-null (callPackage passes all available matching names).

EDIT: maybe allow two standard variants, for simplicity – one light as it's now to use in curl, and another using all the features. Still, it seems to make little sense to me until some packages actually uses the full version.

I think options are better for this eg. development/interpreters/erlang/R18.nix
Using null values for packages can result in confusing errors when trying to use them in paths for example and it's easier to disable an option by default.

Ah ok lesson learned about CallPackage.
Yes boolean option flags seems like the way to go. I've seen that done in the lighttpd definition also.

@vcunat
I proposed a light refactor of the nghttp2 definition which doesn't break the 'normal' build but allows for options to be used if desired. See commit 745ea7a above.