depot/third_party/nixpkgs/doc/languages-frameworks/coq.section.md

Coq and coq packages

Coq derivation: coq

The Coq derivation is overridable through the coq.override overrides, where overrides is an attribute set which contains the arguments to override. We recommend overriding either of the following

• version (optional, defaults to the latest version of Coq selected for nixpkgs, see pkgs/top-level/coq-packages to witness this choice), which follows the conventions explained in the coqPackages section below,
• customOCamlPackages (optional, defaults to null, which lets Coq choose a version automatically), which can be set to any of the ocaml packages attribute of ocaml-ng (such as ocaml-ng.ocamlPackages_4_10 which is the default for Coq 8.11 for example).
• coq-version (optional, defaults to the short version e.g. "8.10"), is a version number of the form "x.y" that indicates which Coq's version build behavior to mimic when using a source which is not a release. E.g. coq.override { version = "d370a9d1328a4e1cdb9d02ee032f605a9d94ec7a"; coq-version = "8.10"; }.

The associated package set can be obtained using mkCoqPackages coq, where coq is the derivation to use.

Coq packages attribute sets: coqPackages

The recommended way of defining a derivation for a Coq library, is to use the coqPackages.mkCoqDerivation function, which is essentially a specialization of mkDerivation taking into account most of the specifics of Coq libraries. The following attributes are supported:

• pname (required) is the name of the package,
• version (optional, defaults to null), is the version to fetch and build, this attribute is interpreted in several ways depending on its type and pattern:
  • if it is a known released version string, i.e. from the release attribute below, the according release is picked, and the version attribute of the resulting derivation is set to this release string,
  • if it is a majorMinor "x.y" prefix of a known released version (as defined above), then the latest "x.y.z" known released version is selected (for the ordering given by versionAtLeast),
  • if it is a path or a string representing an absolute path (i.e. starting with "/"), the provided path is selected as a source, and the version attribute of the resulting derivation is set to "dev",
  • if it is a string of the form owner:branch then it tries to download the branch of owner owner for a project of the same name using the same vcs, and the version attribute of the resulting derivation is set to "dev", additionally if the owner is not provided (i.e. if the owner: prefix is missing), it defaults to the original owner of the package (see below),
  • if it is a string of the form "#N", and the domain is github, then it tries to download the current head of the pull request #N from github,
• defaultVersion (optional). Coq libraries may be compatible with some specific versions of Coq only. The defaultVersion attribute is used when no version is provided (or if version = null) to select the version of the library to use by default, depending on the context. This selection will mainly depend on a coq version number but also possibly on other packages versions (e.g. mathcomp). If its value ends up to be null, the package is marked for removal in end-user coqPackages attribute set.
• release (optional, defaults to {}), lists all the known releases of the library and for each of them provides an attribute set with at least a sha256 attribute (you may put the empty string "" in order to automatically insert a fake sha256, this will trigger an error which will allow you to find the correct sha256), each attribute set of the list of releases also takes optional overloading arguments for the fetcher as below (i.e.domain, owner, repo, rev assuming the default fetcher is used) and optional overrides for the result of the fetcher (i.e. version and src).
• fetcher (optional, defaults to a generic fetching mechanism supporting github or gitlab based infrastructures), is a function that takes at least an owner, a repo, a rev, and a hash and returns an attribute set with a version and src.
• repo (optional, defaults to the value of pname),
• owner (optional, defaults to "coq-community").
• domain (optional, defaults to "github.com"), domains including the strings "github" or "gitlab" in their names are automatically supported, otherwise, one must change the fetcher argument to support them (cf pkgs/development/coq-modules/heq/default.nix for an example),
• releaseRev (optional, defaults to (v: v)), provides a default mapping from release names to revision hashes/branch names/tags,
• displayVersion (optional), provides a way to alter the computation of name from pname, by explaining how to display version numbers,
• namePrefix (optional, defaults to [ "coq" ]), provides a way to alter the computation of name from pname, by explaining which dependencies must occur in name,
• nativeBuildInputs (optional), is a list of executables that are required to build the current derivation, in addition to the default ones (namely which, dune and ocaml depending on whether useDune, useDuneifVersion and mlPlugin are set).
• extraNativeBuildInputs (optional, deprecated), an additional list of derivation to add to nativeBuildInputs,
• overrideNativeBuildInputs (optional) replaces the default list of derivation to which nativeBuildInputs and extraNativeBuildInputs adds extra elements,
• buildInputs (optional), is a list of libraries and dependencies that are required to build and run the current derivation, in addition to the default one [ coq ],
• extraBuildInputs (optional, deprecated), an additional list of derivation to add to buildInputs,
• overrideBuildInputs (optional) replaces the default list of derivation to which buildInputs and extraBuildInputs adds extras elements,
• propagatedBuildInputs (optional) is passed as is to mkDerivation, we recommend to use this for Coq libraries and Coq plugin dependencies, as this makes sure the paths of the compiled libraries and plugins will always be added to the build environments of subsequent derivation, which is necessary for Coq packages to work correctly,
• mlPlugin (optional, defaults to false). Some extensions (plugins) might require OCaml and sometimes other OCaml packages. Standard dependencies can be added by setting the current option to true. For a finer grain control, the coq.ocamlPackages attribute can be used in nativeBuildInputs, buildInputs, and propagatedBuildInputs to depend on the same package set Coq was built against.
• useDuneifVersion (optional, default to (x: false) uses Dune to build the package if the provided predicate evaluates to true on the version, e.g. useDuneifVersion = versions.isGe "1.1" will use dune if the version of the package is greater or equal to "1.1",
• useDune (optional, defaults to false) uses Dune to build the package if set to true, the presence of this attribute overrides the behavior of the previous one.
• opam-name (optional, defaults to concatenating with a dash separator the components of namePrefix and pname), name of the Dune package to build.
• enableParallelBuilding (optional, defaults to true), since it is activated by default, we provide a way to disable it.
• extraInstallFlags (optional), allows to extend installFlags which initializes the variable COQMF_COQLIB so as to install in the proper subdirectory. Indeed Coq libraries should be installed in $(out)/lib/coq/${coq.coq-version}/user-contrib/. Such directories are automatically added to the $COQPATH environment variable by the hook defined in the Coq derivation.
• setCOQBIN (optional, defaults to true), by default, the environment variable $COQBIN is set to the current Coq's binary, but one can disable this behavior by setting it to false,
• useMelquiondRemake (optional, default to null) is an attribute set, which, if given, overloads the preConfigurePhases, configureFlags, buildPhase, and installPhase attributes of the derivation for a specific use in libraries using remake as set up by Guillaume Melquiond for flocq, gappalib, interval, and coquelicot (see the corresponding derivation for concrete examples of use of this option). For backward compatibility, the attribute useMelquiondRemake.logpath must be set to the logical root of the library (otherwise, one can pass useMelquiondRemake = {} to activate this without backward compatibility).
• dropAttrs, keepAttrs, dropDerivationAttrs are all optional and allow to tune which attribute is added or removed from the final call to mkDerivation.

It also takes other standard mkDerivation attributes, they are added as such, except for meta which extends an automatically computed meta (where the platform is the same as coq and the homepage is automatically computed).

Here is a simple package example. It is a pure Coq library, thus it depends on Coq. It builds on the Mathematical Components library, thus it also takes some mathcomp derivations as extraBuildInputs.

{ lib, mkCoqDerivation, version ? null
, coq, mathcomp, mathcomp-finmap, mathcomp-bigenough }:

mkCoqDerivation {
  /* namePrefix leads to e.g. `name = coq8.11-mathcomp1.11-multinomials-1.5.2` */
  namePrefix = [ "coq" "mathcomp" ];
  pname = "multinomials";
  owner = "math-comp";
  inherit version;
  defaultVersion = with lib.versions; lib.switch [ coq.version mathcomp.version ] [
      { cases = [ (range "8.7" "8.12") (isEq "1.11") ];        out = "1.5.2"; }
      { cases = [ (range "8.7" "8.11") (range "1.8" "1.10") ]; out = "1.5.0"; }
      { cases = [ (range "8.7" "8.10") (range "1.8" "1.10") ]; out = "1.4"; }
      { cases = [ (isEq "8.6")         (range "1.6" "1.7") ];  out = "1.1"; }
    ] null;
  release = {
    "1.5.2".sha256 = "15aspf3jfykp1xgsxf8knqkxv8aav2p39c2fyirw7pwsfbsv2c4s";
    "1.5.1".sha256 = "13nlfm2wqripaq671gakz5mn4r0xwm0646araxv0nh455p9ndjs3";
    "1.5.0".sha256 = "064rvc0x5g7y1a0nip6ic91vzmq52alf6in2bc2dmss6dmzv90hw";
    "1.5.0".rev    = "1.5";
    "1.4".sha256   = "0vnkirs8iqsv8s59yx1fvg1nkwnzydl42z3scya1xp1b48qkgn0p";
    "1.3".sha256   = "0l3vi5n094nx3qmy66hsv867fnqm196r8v605kpk24gl0aa57wh4";
    "1.2".sha256   = "1mh1w339dslgv4f810xr1b8v2w7rpx6fgk9pz96q0fyq49fw2xcq";
    "1.1".sha256   = "1q8alsm89wkc0lhcvxlyn0pd8rbl2nnxg81zyrabpz610qqjqc3s";
    "1.0".sha256   = "1qmbxp1h81cy3imh627pznmng0kvv37k4hrwi2faa101s6bcx55m";
  };

  propagatedBuildInputs =
    [ mathcomp.ssreflect mathcomp.algebra mathcomp-finmap mathcomp-bigenough ];

  meta = {
    description = "Coq/SSReflect Library for Monoidal Rings and Multinomials";
    license = lib.licenses.cecill-c;
  };
}

Three ways of overriding Coq packages

There are three distinct ways of changing a Coq package by overriding one of its values: .override, overrideCoqDerivation, and .overrideAttrs. This section explains what sort of values can be overridden with each of these methods.

.override

.override lets you change arguments to a Coq derivation. In the case of the multinomials package above, .override would let you override arguments like mkCoqDerivation, version, coq, mathcomp, mathcom-finmap, etc.

For example, assuming you have a special mathcomp dependency you want to use, here is how you could override the mathcomp dependency:

multinomials.override {
  mathcomp = my-special-mathcomp;
}

In Nixpkgs, all Coq derivations take a version argument. This can be overridden in order to easily use a different version:

coqPackages.multinomials.override {
  version = "1.5.1";
}

Refer to for all the different formats that you can potentially pass to version, as well as the restrictions.

overrideCoqDerivation

The overrideCoqDerivation function lets you easily change arguments to mkCoqDerivation. These arguments are described in .

For example, here is how you could locally add a new release of the multinomials library, and set the defaultVersion to use this release:

coqPackages.lib.overrideCoqDerivation
  {
    defaultVersion = "2.0";
    release."2.0".sha256 = "1lq8x86vd3vqqh2yq6hvyagpnhfq5wmk5pg2z0xq7b7dbbbhyfkk";
  }
  coqPackages.multinomials

.overrideAttrs

.overrideAttrs lets you override arguments to the underlying stdenv.mkDerivation call. Internally, mkCoqDerivation uses stdenv.mkDerivation to create derivations for Coq libraries. You can override arguments to stdenv.mkDerivation with .overrideAttrs.

For instance, here is how you could add some code to be performed in the derivation after installation is complete:

coqPackages.multinomials.overrideAttrs (oldAttrs: {
  postInstall = oldAttrs.postInstall or "" + ''
    echo "you can do anything you want here"
  '';
})