gopass: fix impurity which breaks gopass after 'nix-store --gc'

gopass maintains a ~/.cache/gopass/gpg-binary.loc file
which stores an absolute path to the gpg executable,
overriding (and ignoring) the environment $PATH.

This creates a situation where gopass will work for a period of time
after install, but after gpg is upgraded and a 'nix-store --gc' is
performed, the cached gpg path will throw an error.

A gopass maintainer has declared this a wont-fix in
https://github.com/gopasspw/gopass/issues/1662

As a workaround, add a --run clause in the wrapper script
that removes this cache file.

Once (if) upstream fixes this issue, this cruft can be removed.

Signed-off-by: Sirio Balmelli <sirio@b-ad.ch>

pkgs/tools/security/gopass/default.nix

@@ -46,10 +46,12 @@ buildGoModule rec {
     ln -s $out/bin/gopass $out/bin/pass
   '';
 
+  # --run to work around WONTFIX in https://github.com/gopasspw/gopass/issues/1662
   postFixup = ''
     for bin in $out/bin/*; do
       wrapProgram $bin \
-        --prefix PATH : "${wrapperPath}"
+        --prefix PATH : "${wrapperPath}" \
+        --run 'rm -f "''${XDG_CONFIG_HOME:-~/.config}/gopass/gpg-binary.loc"'
     done
   '';