Fix conflicting flag definitions #254 (#258)

Author: hamishmack

docs/user-guide/projects.md

@@ -30,8 +30,8 @@ let
       #  packages.cbors.package.ghcOptions = "-Werror";
       #  packages.cbors.patches = [ ./one.patch ];
       #  packages.cbors.flags.optimize-gmp = false;
-      # It may be better to set flags in stack.yaml instead (overrides will
-      # be included for them automatically by `stack-to-nix`).
+      # It may be better to set flags in stack.yaml instead
+      # (`stack-to-nix` will include them as defaults).
     ];
   };
 
@@ -44,12 +44,9 @@ let
       # example:
       #  packages.cbors.package.ghcOptions = "-Werror";
       #  packages.cbors.patches = [ ./one.patch ];
-      # To override a flag you will need to use mkOverride to make
-      # it clear that you wish to replace the value found in the
-      # `plan.json` file (all the flags values are included there
-      # by `cabal`).
-      #  packages.cbors.flags.optimize-gmp = stdenv.lib.mkOverride 10 false;
-      # It may be better to set flags in `cabal.project` instead.
+      #  packages.cbors.flags.optimize-gmp = false;
+      # It may be better to set flags in `cabal.project` instead
+      # (`plan-to-nix` will include them as defaults).
     ];
   };
 

nix-tools/nix-tools-src.json

@@ -1,7 +1,7 @@
 {
   "url": "https://github.com/input-output-hk/nix-tools",
-  "rev": "87d97c50a53e421ed016d4c9a1dc41f9e6edda53",
-  "date": "2019-10-12T14:56:33+08:00",
-  "sha256": "1zvk13haiiyb6mcmypjn20i6vcx98y8zp5ipj0vpbflpg7f6rldm",
+  "rev": "1b3d624d6f23ae932508d54954a42a5e489e06a5",
+  "date": "2019-10-13T14:17:51+08:00",
+  "sha256": "13lv0sdrwcc56yl46nfkh9vi10y3cd1jns9ghac56h0y9pdn0jbc",
   "fetchSubmodules": false
 }

test/buildable/default.nix

@@ -9,12 +9,7 @@ let
   });
   pkgSet = mkCabalProjectPkgSet {
     plan-pkgs = plan.pkgs;
-    # We need mkOverride to override the value from `plan.json`.
-    # Normally we could set the flag in `cabal.project`,
-    # but for this test that does not work because then cabal would
-    # see the exe is not buildable and exclude it before haskell.nix
-    # can.
-    modules = [ { packages.buildable-test.flags.exclude-broken = mkOverride 10 true; } ];
+    modules = [ { packages.buildable-test.flags.exclude-broken = true; } ];
   };
   packages = pkgSet.config.hsPkgs;
 in