Expose finalPackages (#68)

* Expose finalPackages

* Check docs in tests

* Add docs.sh script

* Turn haskell-project.nix into a module

* flake-module.nix: Refactor, move to create single perSystem module

Co-authored-by: Sridhar Ratnakumar <[email protected]>

CHANGELOG.md

@@ -7,6 +7,7 @@
 - API changes
     - #37: Group `buildTools` (renamed to `tools`), `hlsCheck` and `hlintCheck` under the `devShell` submodule option; and allow disabling them all using `devShell.enable = false;` (useful if you want haskell-flake to produce just the package outputs).
     - #64: Remove hlintCheck (use [treefmt-nix](https://github.com/numtide/treefmt-nix#flake-parts) instead)
+    - #52: Expose the final package set (API provisional)
 
 ## 0.1.0
 

docs.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env sh
+
+# Renders the docs, prints the location of the docs, opens the docs if possible
+#
+# Does not run the link checker. That's done in runtest.sh.
+
+nix --option sandbox false \
+    build --override-input haskell-flake path:${FLAKE} \
+    -L --show-trace \
+    github:hercules-ci/flake.parts-website \
+    "$@"
+
+echo "Docs rendered to $PWD/result/options/haskell-flake.html"
+
+# Works on linux
+if type xdg-open &>/dev/null; then
+  xdg-open result/options/haskell-flake.html
+fi

flake-module.nix

@@ -71,7 +71,8 @@ in
               };
             };
           };
-          projectSubmodule = types.submodule (args@{ name, config, lib, ... }: {
+          projectSubmodule = types.submoduleWith { specialArgs = { inherit pkgs self; }; modules = [ ./haskell-project.nix
+          {
             options = {
               haskellPackages = mkOption {
                 type = types.attrsOf raw;
@@ -133,37 +134,49 @@ in
                   This is an internal option, not meant to be set by the user.
                 '';
               };
+
+              # Derived options
+
+              finalPackages = mkOption {
+                type = types.attrsOf raw;
+                readOnly = true;
+                description = ''
+                  The final package set, based `haskellPackages` plus
+                  the additions and overrides specified in the other options.
+                '';
+              };
+              finalOverlay = mkOption {
+                type = types.raw;
+                readOnly = true;
+                internal = true;
+              };
             };
-            config = import ./haskell-project.nix (args // { inherit self pkgs; });
-          });
+          } ]; };
         in
         {
           options.haskellProjects = mkOption {
             description = "Haskell projects";
             type = types.attrsOf projectSubmodule;
           };
-        });
-  };
 
-  config = {
-    perSystem = { config, self', lib, inputs', pkgs, ... }:
-      let
-        # Like mapAttrs, but merges the values (also attrsets) of the resulting attrset.
-        flatAttrMap = f: attrs: lib.mkMerge (lib.attrValues (lib.mapAttrs f attrs));
-      in
-      {
-        packages =
-          flatAttrMap (_: project: project.outputs.packages) config.haskellProjects;
-        devShells =
-          flatAttrMap
-            (_: project:
-              lib.optionalAttrs project.devShell.enable project.outputs.devShells)
-            config.haskellProjects;
-        checks =
-          flatAttrMap
-            (_: project:
-              lib.optionalAttrs project.devShell.enable project.outputs.checks)
-            config.haskellProjects;
-      };
+          config = let
+            # Like mapAttrs, but merges the values (also attrsets) of the resulting attrset.
+            mergeMapAttrs = f: attrs: lib.mkMerge (lib.mapAttrsToList f attrs);
+          in
+          {
+            packages =
+              mergeMapAttrs (_: project: project.outputs.packages) config.haskellProjects;
+            devShells =
+              mergeMapAttrs
+                (_: project:
+                  lib.optionalAttrs project.devShell.enable project.outputs.devShells)
+                config.haskellProjects;
+            checks =
+              mergeMapAttrs
+                (_: project:
+                  lib.optionalAttrs project.devShell.enable project.outputs.checks)
+                config.haskellProjects;
+          };
+        });
   };
 }

haskell-project.nix

@@ -25,7 +25,8 @@ let
       '';
 in
 {
-  outputs =
+
+  config =
     let
       projectKey = name;
 
@@ -78,29 +79,44 @@ in
       };
     in
     {
-      packages =
-        let
-          mapKeys = f: attrs: lib.mapAttrs' (n: v: { name = f n; value = v; }) attrs;
-          # Prefix package names with the project name (unless
-          # project is named `default`)
-          dropDefaultPrefix = packageName:
-            if projectKey == "default"
-            then packageName
-            else "${projectKey}-${packageName}";
-        in
-        mapKeys dropDefaultPrefix
-          (lib.mapAttrs
-            (name: _: finalPackages."${name}")
-            config.packages);
+      finalPackages = config.haskellPackages.extend config.finalOverlay;
 
-      devShells."${projectKey}" = devShell;
+      finalOverlay = lib.composeManyExtensions [
+        # The order here matters.
+        #
+        # User's overrides (cfg.overrides) is applied **last** so
+        # as to give them maximum control over the final package
+        # set used.
+        localPackagesOverlay
+        (pkgs.haskell.lib.packageSourceOverrides config.source-overrides)
+        config.overrides
+      ];
 
-    } // lib.optionalAttrs config.devShell.hlsCheck.enable {
+      outputs = {
+        packages =
+          let
+            mapKeys = f: attrs: lib.mapAttrs' (n: v: { name = f n; value = v; }) attrs;
+            # Prefix package names with the project name (unless
+            # project is named `default`)
+            dropDefaultPrefix = packageName:
+              if projectKey == "default"
+              then packageName
+              else "${projectKey}-${packageName}";
+          in
+          mapKeys dropDefaultPrefix
+            (lib.mapAttrs
+              (name: _: finalPackages."${name}")
+              config.packages);
 
-      checks."${projectKey}-hls" =
-        runCommandInSimulatedShell
-          devShell
-          self "${projectKey}-hls-check"
-          { } "haskell-language-server";
+        devShells."${projectKey}" = devShell;
+
+      } // lib.optionalAttrs config.devShell.hlsCheck.enable {
+
+        checks."${projectKey}-hls" =
+          runCommandInSimulatedShell
+            devShell
+            self "${projectKey}-hls-check"
+            { } "haskell-language-server";
+      };
     };
 }

runtest.sh

@@ -1,18 +1,35 @@
 set -e
 
+if [ "$(uname)" == "Darwin" ]; then
+    SYSTEM=aarch64-darwin
+    function logHeader {
+        echo "\n||| $@"
+    }
+else
+    SYSTEM=x86_64-linux
+    function logHeader {
+        echo -e "\n||| $@"
+    }
+fi
+
 FLAKE=$(pwd)
 cd ./test
 
 # First, build the flake.
-echo "\n||| Testing nix build"
+logHeader "Testing nix build"
 nix build --override-input haskell-flake path:${FLAKE}
 # Run the devshell test script in a nix develop shell.
-echo "\n||| Testing nix devshell"
+logHeader "Testing nix devshell"
 nix develop --override-input haskell-flake path:${FLAKE} -c ./test.sh
 # Test non-devshell features:
 # Checks
-echo "\n||| Testing nix flake checks"
+logHeader "Testing nix flake checks"
 nix --option sandbox false \
     build --override-input haskell-flake path:${FLAKE} -L .#check
 
-echo "\n||| All tests passed!"
+logHeader "Testing docs"
+nix build --override-input haskell-flake path:${FLAKE} \
+    --option log-lines 1000 --show-trace \
+    github:hercules-ci/flake.parts-website#checks.${SYSTEM}.linkcheck
+
+logHeader "All tests passed!"