WIP

lib/cover-project.nix

@@ -0,0 +1,44 @@
+{ pkgs, stdenv, lib, haskellLib }:
+
+project:
+
+let
+  coverageReports = lib.mapAttrsToList (n: package: package.coverageReport) project;
+in
+stdenv.mkDerivation {
+  name = "coverage-report";
+
+  phases = ["buildPhase"];
+
+  buildInputs = (with pkgs.haskellPackages; [
+    ghc
+  ]);
+
+  buildPhase = ''
+    mkdir -p $out/share/hpc/tix/all
+    mkdir -p $out/share/hpc/mix/
+
+    findMixDir() {
+      find $1 -iwholename "*/hpc/vanilla/mix" -exec find {} -maxdepth 1 -type d -iwholename "*/mix/*" \; -quit
+    }
+
+    findCabalFile() {
+      find $1 -iname "*.cabal" -print -quit
+    }
+
+    # Create tix file with test run information for all packages
+    tixFile="$out/share/hpc/tix/all/all.tix"
+    hpcSumCmd=("hpc" "sum" "--union" "--output=$tixFile")
+    for report in ${lib.concatStringsSep " " coverageReports}; do
+      for tix in $(find $report -iwholename "*.tix" -type f); do
+        hpcSumCmd+=("$tix")
+      done
+
+      # Copy mix and tix information over from each report
+      cp -R $report/share/hpc/mix/* $out/share/hpc/mix
+      cp -R $report/share/hpc/tix/* $out/share/hpc/tix
+    done
+
+    eval "''${hpcSumCmd[@]}"
+  '';
+}

lib/default.nix

@@ -244,7 +244,7 @@ in {
     inherit stdenv lib haskellLib pkgs;
   };
 
-  projectCoverageReport = import ./cover-files-only.nix {
+  projectCoverageReport = import ./cover-project.nix {
     inherit stdenv lib haskellLib pkgs;
   };