fish-foreign-env: hide warnings when setting PATH

pkgs/shells/fish-foreign-env/default.nix

@@ -11,15 +11,17 @@ stdenv.mkDerivation rec {
     sha256 = "0lwp6hy3kfk7xfx4xvbk1ir8zkzm7gfjbm4bf6xg1y6iw9jq9dnl";
   };
 
-  buildCommand = ''
+  installPhase = ''
     mkdir -p $out/share/fish-foreign-env/functions/
-    cp $src/functions/* $out/share/fish-foreign-env/functions/
+    cp functions/* $out/share/fish-foreign-env/functions/
     sed -e "s|sed|${gnused}/bin/sed|" \
         -e "s|bash|${bash}/bin/bash|" \
         -e "s|\| tr|\| ${coreutils}/bin/tr|" \
         -i $out/share/fish-foreign-env/functions/*
   '';
 
+  patches = [ ./hide-path-warnings.patch ];
+
   meta = with stdenv.lib; {
     description = "A foreign environment interface for Fish shell";
     license = licenses.mit;

pkgs/shells/fish-foreign-env/hide-path-warnings.patch

@@ -0,0 +1,16 @@
+diff --git a/functions/fenv.apply.fish b/functions/fenv.apply.fish
+index 34a25e3..6837e7f 100644
+--- a/functions/fenv.apply.fish
++++ b/functions/fenv.apply.fish
+@@ -30,8 +30,9 @@ function fenv.apply
+ 
+         if test "$key" = 'PATH'
+           set value (echo $value | tr ':' '\n')
++          set -g -x $key $value ^/dev/null
++        else
++          set -g -x $key $value
+         end
+-
+-        set -g -x $key $value
+     end
+ end