Add shell.allDeps as a fix

#1769 added all the tool dependencies of the hsPkgs in a project to the shell.  This is great for cabal projects where the set of packages will be limited to those in the plan.  It allows these packages to be rebuilt by cabal.

For stack projects however this set is much larger (all of stackage), likely to include unwanted tools and tools that may be broken.

This change adds `shell.allDeps` and defaults it to `false` for stack projects.

Fixes #1793

Author: hamishmack

builder/shell-for.nix

@@ -15,6 +15,7 @@
 , withHoogle ? true
 , withHaddock ? withHoogle
 , exactDeps ? false
+, allToolDeps ? !exactDeps
 , tools ? {}
 , packageSetupDeps ? true
 , enableDWARF ? false
@@ -110,7 +111,7 @@ let
     (uniqueWithName (lib.concatMap (c: c.executableToolDepends)
       # When not using `exactDeps` cabal may try to build arbitrary dependencies
       # so in this case we need to provide the build tools for all of hsPkgs:
-      (if exactDeps then selectedComponents else allHsPkgsComponents)));
+      (if exactDeps || !allToolDeps then selectedComponents else allHsPkgsComponents)));
 
   # Set up a "dummy" component to use with ghcForComponent.
   component = {

modules/shell.nix

@@ -29,6 +29,15 @@
       type = lib.types.bool;
       default = false;
     };
+    allToolDeps = lib.mkOption {
+      type = lib.types.bool;
+      default = !config.exactDeps;
+      description = ''
+        Indicates if the shell should include all the tool dependencies
+        of in the haskell packages in the project.  Defaulted to `false` in
+        stack projects.
+      '';
+    };
     tools = lib.mkOption {
       type = lib.types.attrsOf lib.types.unspecified;
       default = {};

modules/stack-project.nix

@@ -91,4 +91,9 @@ with types;
       description = "Deprecated in favour of `compiler-nix-name`";
     };
   };
+  config = {
+    # For stack projects we normally do not want to include the tool dependencies
+    # of all the hsPkgs (all of stackage).
+    shell.allToolDeps = mkDefault false;
+  };
 }