coqPackages: refactor

1 files changed, 63 insertions, 26 deletions

diff --git a/doc/languages-frameworks/coq.section.md b/doc/languages-frameworks/coq.section.md
index 714e84efc8d..7fa71ddc6f8 100644
--- a/doc/languages-frameworks/coq.section.md
+++ b/doc/languages-frameworks/coq.section.md
@@ -1,40 +1,77 @@
-# Coq {#sec-language-coq}
+# Coq and coq packages {#sec-language-coq}
 
-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.
+## Coq derivation: `coq`
 
-Some extensions (plugins) might require OCaml and sometimes other OCaml packages. The `coq.ocamlPackages` attribute can be used to depend on the same package set Coq was built against.
+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,
++ `customOCamlPackage` (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"; }`.
 
-Coq libraries may be compatible with some specific versions of Coq only. The `compatibleCoqVersions` attribute is used to precisely select those versions of Coq that are compatible with this derivation.
+## Coq packages attribute sets: `coqPackages`
 
-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 `mathcomp` as `buildInputs`. Its `Makefile` has been generated using `coq_makefile` so we only have to set the `$COQLIB` variable at install time.
+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 use the shell command `nix-prefetch-url --unpack <archive-url>` to find it, where `<archive-url>` is for example `https://github.com/owner/repo/archive/version.tar.gz`), 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, default 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 `sha256` 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), provides a way to alter the computation of `name` from `pname`, by explaining which dependencies must occur in `name`,
+- `extraBuildInputs` (optional), by default `buildInputs` just contains `coq`, this allows to add more build inputs,
+- `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 `extraBuildInputs` to depend on the same package set Coq was built against.
+- `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`.
 
 ```nix
-{ stdenv, fetchFromGitHub, coq, mathcomp }:
-
-stdenv.mkDerivation rec {
-  name = "coq${coq.coq-version}-multinomials-${version}";
-  version = "1.0";
-  src = fetchFromGitHub {
-    owner = "math-comp";
-    repo = "multinomials";
-    rev = version;
-    sha256 = "1qmbxp1h81cy3imh627pznmng0kvv37k4hrwi2faa101s6bcx55m";
+{ coq, mkCoqDerivation, mathcomp, mathcomp-finmap, mathcomp-bigenough,
+  lib, version ? null }:
+with lib; 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 versions; switch [ coq.version mathcomp.version ] [
+      { cases = [ (range "8.7" "8.12")  "1.11.0" ];             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 = [ "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";
   };
 
-  buildInputs = [ coq ];
-  propagatedBuildInputs = [ mathcomp ];
-
-  installFlags = "COQLIB=$(out)/lib/coq/${coq.coq-version}/";
+  propagatedBuildInputs =
+    [ mathcomp.ssreflect mathcomp.algebra mathcomp-finmap mathcomp-bigenough ];
 
   meta = {
     description = "A Coq/SSReflect Library for Monoidal Rings and Multinomials";
-    inherit (src.meta) homepage;
-    license = stdenv.lib.licenses.cecill-b;
-    inherit (coq.meta) platforms;
-  };
-
-  passthru = {
-    compatibleCoqVersions = v: builtins.elem v [ "8.5" "8.6" "8.7" ];
+    license = licenses.cecill-c;
   };
 }
 ```