Fix hadrian eval time dependency on buildPackages.srcOnly

Author: hamishmack

compiler/ghc/default.nix

@@ -297,6 +297,18 @@ let
         subDir = "hadrian";
         includeSiblings = true;
       };
+      # When building the plan we do not need a patched version
+      # of the source and `buildPackages.srcOnly` requires introduces
+      # a dependency on a build machine.
+      evalSrc = haskell-nix.haskellLib.cleanSourceWith {
+        src = {
+          name = "hadrian";
+          outPath = src;
+          filterPath = { path, ... }: path;
+        };
+        subDir = "hadrian";
+        includeSiblings = true;
+      };
     };
 
   hadrian = hadrianProject.hsPkgs.hadrian.components.exes.hadrian;

lib/call-cabal-project-to-nix.nix

@@ -1,6 +1,7 @@
 { pkgs, cacert, index-state-hashes, haskellLib }:
 { name          ? src.name or null # optional name for better error messages
 , src
+, evalSrc ? src
 , materialized-dir ? ../materialized
 , compiler-nix-name    # The name of the ghc compiler to use eg. "ghc884"
 , index-state   ? null # Hackage index-state, eg. "2019-10-10T00:00:00Z"
@@ -94,13 +95,13 @@ in let
   ghc = if ghc' ? latestVersion
     then __trace "WARNING: ${ghc'.version} is out of date, consider using upgrading to ${ghc'.latestVersion}." ghc'
     else ghc';
-  subDir' = src.origSubDir or "";
+  subDir' = evalSrc.origSubDir or "";
   subDir = pkgs.lib.strings.removePrefix "/" subDir';
 
   cleanedSource = haskellLib.cleanSourceWith {
     name = if name != null then "${name}-root-cabal-files" else "source-root-cabal-files";
-    src = src.origSrc or src;
-    filter = path: type: (!(src ? filter) || src.filter path type) && (
+    src = evalSrc.origSrc or evalSrc;
+    filter = path: type: (!(evalSrc ? filter) || evalSrc.filter path type) && (
       type == "directory" ||
       pkgs.lib.any (i: (pkgs.lib.hasSuffix i path)) [ ".cabal" "package.yaml" ]); };
 

modules/cabal-project.nix

@@ -56,15 +56,15 @@ in {
     };
     cabalProject = mkOption {
       type = nullOr lines;
-      default = readIfExists config.src config.cabalProjectFileName;
+      default = readIfExists config.evalSrc config.cabalProjectFileName;
     };
     cabalProjectLocal = mkOption {
       type = nullOr lines;
-      default = readIfExists config.src "${config.cabalProjectFileName}.local";
+      default = readIfExists config.evalSrc "${config.cabalProjectFileName}.local";
     };
     cabalProjectFreeze = mkOption {
       type = nullOr lines;
-      default = readIfExists config.src "${config.cabalProjectFileName}.freeze";
+      default = readIfExists config.evalSrc "${config.cabalProjectFileName}.freeze";
     };
     ghc = mkOption {
       type = nullOr package;

modules/project-common.nix

@@ -75,6 +75,18 @@ with lib.types;
           };
       '';
     };
+    evalSrc = mkOption {
+      type = either path package;
+      default = config.src;
+      description = ''
+        Allows a different version of the src to be used at eval time.
+        This is useful when building the source may require a build machine.
+        To avoid an eval time dependency on a build machine set `evalSrc`
+        to either:
+          * A version of the source built using `evalPackages`
+          * A version of the source that does not require building
+      '';
+    };
     hsPkgs = lib.mkOption {
       type = lib.types.unspecified;
     };