From 64e52fb36022af7186bbe21807619ec3ea7464d8 Mon Sep 17 00:00:00 2001
From: Samuel Evans-Powell <mail@sevanspowell.net>
Date: Mon, 3 Aug 2020 12:26:21 +0800
Subject: [PATCH] WIP

---
 lib/cover-files-only.nix | 100 +++++++++++++++++++++++++++++++++++++++
 lib/default.nix          |   4 ++
 overlays/haskell.nix     |  19 +++++++-
 3 files changed, 121 insertions(+), 2 deletions(-)
 create mode 100644 lib/cover-files-only.nix

diff --git a/lib/cover-files-only.nix b/lib/cover-files-only.nix
new file mode 100644
index 0000000000..3709e66e4c
--- /dev/null
+++ b/lib/cover-files-only.nix
@@ -0,0 +1,100 @@
+{ pkgs, stdenv, lib, haskellLib }:
+
+projects:
+
+let
+  buildWithCoverage = builtins.map (d: d.covered);
+  runCheck = builtins.map (d: haskellLib.check d);
+
+  # drvs' = buildWithCoverage drvs;
+  # drvSources = builtins.map (d: d.src.outPath) drvs;
+  # testsWithCoverage = buildWithCoverage tests;
+  # checks' = runCheck testsWithCoverage;
+  drvs' = null;
+  drvSources = null;
+  testsWithCoverage = null;
+  checks' = null;
+
+  projects' = builtins.map (p:
+    rec {
+      name = p.name;
+      drv = p.drv.covered;
+      testsWithCoverage = buildWithCoverage p.tests;
+      checks = runCheck testsWithCoverage;
+    }
+  ) projects;
+
+  doThis = p: ''
+    mkdir $out/share/hpc/mix/${p.name}
+
+    for drv in ${lib.concatStringsSep " " ([ p.drv ] ++ p.testsWithCoverage)}; do
+      # Copy over mix files
+      local mixDir=$(findMixDir $drv)
+      echo "MixDir: $mixDir"
+      cp -R $mixDir/* $out/share/hpc/mix/${p.name}
+    done
+  '';
+
+in stdenv.mkDerivation {
+  name = "coverage-report";
+
+  inherit checks' drvs' drvSources;
+
+  phases = ["buildPhase"];
+
+  buildInputs = (with pkgs.haskellPackages; [
+    ghc
+  ]);
+
+  buildPhase = ''
+    mkdir -p $out/share/hpc/mix
+    mkdir -p $out/share/hpc/tix
+    mkdir -p $out/share/hpc/tix/all
+
+    findMixDir() {
+      find $1 -iwholename "*/hpc/vanilla/mix" -exec find {} -maxdepth 1 -type d -iwholename "*/mix/*" \; -quit
+    }
+
+    findCabalFile() {
+      find $1 -iname "*.cabal" -print -quit
+    }
+
+    ${lib.concatStringsSep "\n" (builtins.map doThis projects')}
+
+  '';
+
+    # for check in ${lib.concatStringsSep " " checks'}; do
+    #   cp -R $check/share/hpc/tix/* $out/share/hpc/tix
+    # done
+
+    # # For each derivation to generate coverage for
+    # for drv in ${lib.concatStringsSep " " (drvs' ++ testsWithCoverage)}; do
+    #   # Copy over mix files
+    #   local mixDir=$(findMixDir $drv)
+    #   echo "MixDir: $mixDir"
+    #   cp -R $mixDir/* $out/share/hpc/mix/
+    # done
+
+    # excludedModules=("Main")
+    # for drv in ${lib.concatStringsSep " " drvSources}; do
+    #   # Exclude test modules
+    #   local cabalFile=$(findCabalFile $drv)
+    #   for module in $(${pkgs.cq}/bin/cq $cabalFile testModules | ${pkgs.jq}/bin/jq ".[]"); do
+    #     excludedModules+=("$module")
+    #   done
+    # done
+    # echo "''${excludedModules[@]}"
+
+    # tixFile="$out/share/hpc/tix/all/all.tix"
+    # hpcSumCmd=("hpc" "sum" "--union" "--output=$tixFile")
+    # for check in ${lib.concatStringsSep " " checks'}; do
+    #   for tix in $(find $check -name '*.tix' -print); do
+    #     hpcSumCmd+=("$tix")
+    #   done
+    # done
+    # for exclude in ''${excludedModules[@]}; do
+    #   hpcSumCmd+=("--exclude=$exclude")
+    # done
+    # echo "''${hpcSumCmd[@]}"
+    # eval "''${hpcSumCmd[@]}"
+}
diff --git a/lib/default.nix b/lib/default.nix
index 7402c9eaff..d1b9fc9fdf 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -244,6 +244,10 @@ in {
     inherit stdenv lib haskellLib;
   };
 
+  coverageReport' = import ./cover-files-only.nix {
+    inherit stdenv lib haskellLib pkgs;
+  };
+
   # Use `isCrossHost` to identify when we are cross compiling and
   # the code we are producing will not run on the build system
   # without an emulator.
diff --git a/overlays/haskell.nix b/overlays/haskell.nix
index 7ae5eb7dfc..7c0d2b0fec 100644
--- a/overlays/haskell.nix
+++ b/overlays/haskell.nix
@@ -473,11 +473,13 @@ final: prev: {
                               { compiler.nix-name = args.compiler-nix-name; };
                   extra-hackages = args.extra-hackages or [];
                 };
-            in addProjectAndPackageAttrs {
+            in addProjectAndPackageAttrs rec {
               inherit (pkg-set.config) hsPkgs;
               inherit pkg-set;
               plan-nix = callProjectResults.projectNix;
               inherit (callProjectResults) index-state;
+
+              coverageReport = projectCoverageReport (haskellLib.selectProjectPackages hsPkgs);
             };
 
         # Take `hsPkgs` from the `rawProject` and update all the packages and
@@ -509,7 +511,7 @@ final: prev: {
 
         cabalProject = args: let p = cabalProject' args;
             in p.hsPkgs // {
-              inherit (p) plan-nix;
+              inherit (p) plan-nix coverageReport;
               # Provide `nix-shell -A shells.ghc` for users migrating from the reflex-platform.
               # But we should encourage use of `nix-shell -A shellFor`
               shells.ghc = p.hsPkgs.shellFor {};
@@ -582,6 +584,19 @@ final: prev: {
             } // final.lib.optionalAttrs (p ? stack-nix) { inherit (p) stack-nix; }
               // final.lib.optionalAttrs (p ? plan-nix ) { inherit (p) plan-nix;  };
 
+        projectCoverageReport = packages:
+          let
+            # TODO what if package doesn't have library and/or tests?
+            projectInfo = with final.lib;
+              mapAttrsToList (n: p: {
+                  name = n;
+                  drv = p.components.library;
+                  tests = filter isDerivation (attrValues p.components.tests);
+                }
+              ) packages;
+          in
+            haskellLib.coverageReport' projectInfo;
+
         # Like `cabalProject'`, but for building the GHCJS compiler.
         # This is exposed to allow GHCJS developers to work on the GHCJS
         # code in a nix-shell with `shellFor`.